143982665 x air

IndoorAir QualityTheLatestSamplingandAnalyticalMethods

Second Edition

CRC PressTaylor & Francis Group6000 Broken Sound Parkway NW, Suite 300Boca Raton, FL 33487-2742

© 2011 by Taylor & Francis Group, LLCCRC Press is an imprint of Taylor & Francis Group, an Informa business

No claim to original U.S. Government worksVersion Date: 2011914

International Standard Book Number-13: 978-1-4398-2666-9 (eBook - PDF)

This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint.

Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmit-ted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers.

For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged.

Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe.

Visit the Taylor & Francis Web site athttp://www.taylorandfrancis.com

and the CRC Press Web site athttp://www.crcpress.com

v

Contents

Preface.....................................................................................................................xvAcknowledgments ............................................................................................. xviiAbout the Author ................................................................................................ xix

Section I The Starting Line

1. Historic Overview ..........................................................................................3Evolution of Indoor Air Quality Investigations ..........................................3Litigation ...........................................................................................................5Differences in Health Effects .........................................................................6A Misguided Premise .....................................................................................7Regulations, Requirements, and Guidelines ...............................................7

U.S. Government Directives ......................................................................8EPA National Ambient Air Quality Standards ......................................8OSHA Workplace Standards .....................................................................9ACGIH Workplace Guidelines ................................................................ 10ASHRAE Criteria for General Public ..................................................... 10

ACGIH Guidelines Revisited in Older ASHRAE Standard........... 11International Enforcement and/or Guidelines ................................ 12ASHRAE Criteria for Residences....................................................... 12ASHRAE Criteria for High Performance Buildings ....................... 12

Summary......................................................................................................... 13References ....................................................................................................... 13

2. Investigation Plan......................................................................................... 15Documents Review........................................................................................ 17Building a Walk-Through ............................................................................. 18

Occupied Areas ......................................................................................... 18Air Handling System................................................................................ 19Bathroom Air Exhaust.............................................................................. 20Sewer System ............................................................................................. 21Occupant Activities .................................................................................. 21

Interviews with Facilities Personnel ........................................................... 21Maintenance Staff .......................................................................................... 21

Custodial Staff ...........................................................................................22Observation of Surrounding Areas.............................................................23Assessing Occupant Complaints.................................................................23

Questionnaires .......................................................................................... 24

vi Contents

Types of Questionnaires....................................................................... 24Questionnaire Response Rate ............................................................ 24Informational Data...............................................................................25

Interviews................................................................................................... 27Summary......................................................................................................... 27References ....................................................................................................... 27

3. The Hypothesis ............................................................................................. 29Information Review.......................................................................................30

Building Assessment ................................................................................30Complaint Occupant................................................................................. 31

Hypothesis Development .............................................................................34The Proactive Approach ...............................................................................36Beyond the Scope........................................................................................... 37

Medical Physicians ................................................................................... 37Industrial Hygienists and Toxicologists ................................................38Psychiatrists ...............................................................................................38

Summary......................................................................................................... 39References ....................................................................................................... 39

Section II Omnipresent Bioaerosols

4. Pollen and Spore Allergens ........................................................................43Occurrence of Pollen and Spore Allergens ................................................43

General Information .................................................................................44Spore-Producing Fungi and Bacteria ..................................................... 49Fungi ........................................................................................................... 49

Molds...................................................................................................... 49Mushrooms ........................................................................................... 52Rusts and Smuts ...................................................................................53Slime Molds...........................................................................................54

Bacteria .......................................................................................................55Indoor Source Information ......................................................................55

Sampling Strategy..........................................................................................56Sampling and Analytical Methodologies.................................................... 57

Slit-to-Cover-Slip Sample Cassettes ....................................................... 57Slit-to-Slide Samplers.....................................................................................58

Analytical Methods .................................................................................. 59Commercial Laboratories......................................................................... 59Helpful Hints............................................................................................. 59

Interpretation of Results ...............................................................................60Summary.........................................................................................................66References .......................................................................................................66

Contents vii

5. Viable Microbial Allergens ........................................................................ 67Occurrence of Allergenic Microbes.............................................................. 67

Fungi ...........................................................................................................68Molds ..........................................................................................................68Yeasts...........................................................................................................72Bacteria .......................................................................................................72

Bacillus................................................................................................... 73Thermophilic Actinomycetes ............................................................. 74

Air Sampling Methodologies....................................................................... 74Sampling Strategy..................................................................................... 75

When and Where to Sample............................................................... 75Equipment ............................................................................................. 76Sample Duration................................................................................... 78Sample Numbers .................................................................................. 78Culture Media....................................................................................... 79Procedural Summary...........................................................................83

Diagnostic Sampling Methodologies..........................................................83Sampling Strategy.....................................................................................84Where to Sample .......................................................................................84What to Sample .........................................................................................85Sampling Supplies ....................................................................................85Procedural Summary ...............................................................................86

Interpretation of Results ...............................................................................86Genus Variability ...................................................................................... 87Airborne Exposure Levels ....................................................................... 89Bulk and Surface Sample Results ........................................................... 89

Helpful Hints..................................................................................................90Summary.........................................................................................................90References ....................................................................................................... 91

6. Pathogenic Microbes.................................................................................... 93Airborne Pathogenic Fungi .......................................................................... 94

Disease and Occurrence........................................................................... 94Aspergillus .............................................................................................. 94Histoplasma capsulatum ......................................................................... 96Coccidioides immitis ............................................................................... 97Cryptococcus neoformans .......................................................................99Other Pathogenic Fungi ......................................................................99

Sampling and Analytical Methodologies............................................ 102Interpretation of Results ........................................................................ 103

Airborne Pathogenic Bacteria .................................................................... 103Pathogenic Legionella................................................................................ 104

Sampling and Analytical Methodologies for Legionella ............... 105Interpretation of Results.................................................................... 106Helpful Hints ...................................................................................... 107

viii Contents

Other Pathogenic Bacteria ..................................................................... 108Disease and Occurrence of Prominent Airborne PathogenicBacteria ................................................................................................ 108

Sampling and Analytical Methodologies............................................ 111Interpretation of Results.................................................................... 112

Pathogenic Protozoa .................................................................................... 113Sampling and Analytical Methodology .............................................. 113Interpretation of Results ........................................................................ 114

Viruses........................................................................................................... 114Summary....................................................................................................... 115References ..................................................................................................... 115

7. Toxigenic Microbes .................................................................................... 119Mycotoxins.................................................................................................... 119

Disease and Occurrence......................................................................... 121Sampling and Analytical Methodologies............................................ 123

Fungi Identification............................................................................ 123Toxin Identification ............................................................................ 124

Interpretation of Results ........................................................................ 126Bacterial Endotoxins.................................................................................... 127

Sampling and Analytical Methodology .............................................. 128Interpretation of Results ........................................................................ 130

Summary....................................................................................................... 131References ..................................................................................................... 131

Section III Chemical Unknowns and Gases

8. Volatile Organic Compounds .................................................................. 135Health Effects and Occurrences ................................................................ 136Air Sampling Strategy................................................................................. 139

When to Sample ...................................................................................... 139Where to Sample ..................................................................................... 140How to Sample ........................................................................................ 141

Rationale for Total VOC Screening (As Opposed to ComponentIdentification)................................................................................................ 141Air Sampling and Analytical Methodologies.......................................... 143

Solid Sorbents and Air Sampling Pumps............................................ 145NIOSH Method 1500.......................................................................... 145EPA Method TO-17............................................................................. 147Passive Organic Vapor Monitors...................................................... 149Evacuated Ambient Air Containers ................................................ 151Whole Air Canisters .......................................................................... 152Ambient Air Sampling Bags ............................................................ 154

Contents ix

Analytical Comparisons ........................................................................ 156Helpful Hints ...................................................................................... 158Interpretation of Results.................................................................... 159


9. Mold Volatile Organic Compounds and Mold Detection.................. 163Health Effects and Occurrences ................................................................ 163Sampling for MVOCs .................................................................................. 166

Sampling Strategy................................................................................... 166Sampling Methodology.......................................................................... 167

Screening Methodologies ........................................................................... 168Visual Observations................................................................................ 168Odor Tracking.......................................................................................... 170Moisture Testing ..................................................................................... 171

Interpretation of Results ............................................................................. 173Summary....................................................................................................... 174References ..................................................................................................... 174

10. Carbon Dioxide ........................................................................................... 177Occurrence of Carbon Dioxide .................................................................. 178Sampling Strategy........................................................................................ 179Sampling Methodologies............................................................................ 180

Direct Reading Instrumentation........................................................... 180Colorimetric Detectors ........................................................................... 180

Helpful Hints................................................................................................ 182Interpretation of Results ............................................................................. 183Summary....................................................................................................... 184

11. Carbon Monoxide ....................................................................................... 185Occurrence of Carbon Monoxide .............................................................. 185Sampling Strategy........................................................................................ 187Sampling Methodologies............................................................................ 188

Direct Reading Instrumentation........................................................... 188Colorimetric Detectors ........................................................................... 188

Helpful Hints................................................................................................ 190Interpretation of Results ............................................................................. 190Summary....................................................................................................... 191Reference ....................................................................................................... 191

12. Formaldehyde .............................................................................................. 193Occurrence of Formaldehyde..................................................................... 194Sampling Strategy........................................................................................ 196Sampling Methodologies............................................................................ 197Analytical Methodologies .......................................................................... 201

x Contents

Helpful Hints................................................................................................ 202Interpretation of Results ............................................................................. 202Summary....................................................................................................... 203References ..................................................................................................... 203

13. Product Emissions ...................................................................................... 205Global Response and Product Labelling .................................................. 206Product Emissions Awareness................................................................... 208Sensory Irritation Testing in Environmental Chambers ....................... 211Product Collection ....................................................................................... 212Environmental Chamber and Analytical Methodology........................ 216Measurements of Product Emission Factors............................................ 219Interpretation of Results ............................................................................. 220Summary.......................................................................................................223References .....................................................................................................225

Section IV Identification of Dusts

14. Forensics of Dust ........................................................................................229Occurrences of Forensic Dust ....................................................................230Sampling Methodologies............................................................................ 232

Settled Surface Dust Sampling .............................................................234Specialty Tape .....................................................................................234Clear Tape............................................................................................235Post-it Paper.........................................................................................235Micro-vacuuming...............................................................................235

Airborne Dust Sampling........................................................................236Spore Trap ................................................................................................236

Membrane Filters................................................................................ 237Cascade Impactors .............................................................................238Other Methods....................................................................................238

Bulk Sampling ......................................................................................... 239Textile/Carpet Sampling........................................................................ 239

Analytical Methodologies .......................................................................... 240Visible Light Microscopy ....................................................................... 240Specialized Microscopic Techniques ................................................... 241

X-Ray Diffraction................................................................................ 241Scanning Electron Microscope......................................................... 242Transmission Electron Microscope................................................... 243Electron Microprobe Analyzer......................................................... 244Ion Microprobe Analyzer.................................................................. 244

Commercial Laboratories ........................................................................... 245Summary....................................................................................................... 245References ..................................................................................................... 246

Contents xi

15. Animal Allergenic Dust ............................................................................ 247Animal Allergens ........................................................................................ 248

Mites/Spiders........................................................................................... 248Booklice .................................................................................................... 251Cockroaches and Other Insects ............................................................ 251Domestic Animals ..................................................................................254

Cats .......................................................................................................255Dogs......................................................................................................255Rodents ................................................................................................256Farm Animals ..................................................................................... 257Other Animals .................................................................................... 257

Occurrence of Animal Allergens............................................................... 257Sampling Strategy........................................................................................258Screening for Rodents ................................................................................. 260Sampling Methodologies............................................................................ 260Analytical Methodologies .......................................................................... 263

Human Testing........................................................................................ 263Allergenic Dust Testing...........................................................................264

Interpretation of Results ............................................................................. 265Other Types of Allergenic Substances ...................................................... 268Summary....................................................................................................... 269References ..................................................................................................... 270

Section V Building Systems and Materials

16. HVAC Systems ............................................................................................ 275The Basic Design .......................................................................................... 275HVAC Visual Inspection............................................................................. 278

Outdoor Air Intake ................................................................................. 278Outdoor Air in the Vicinity of Air Intake ........................................... 279Indoor HVAC Equipment Rooms ......................................................... 279Filters.......................................................................................................... 279Condensate Drain Pan............................................................................ 282Fan Housing.............................................................................................284Unit and Duct Liner................................................................................284Supply Registers and Return Air Grills............................................... 286Level of Maintenance .............................................................................288Air Duct.................................................................................................... 289

Strategy and Sampling................................................................................ 290Analyzing the Unknown............................................................................ 292Interpretation Not So Simple ..................................................................... 292Summary....................................................................................................... 293

xii Contents

17. Sewage Systems and Sewer Gases .......................................................... 295Occurrence of Sewer Gases ........................................................................ 296

Hazardous Gases .................................................................................... 296Biological Components........................................................................... 297Noxious Odor Confusion....................................................................... 297

Investigation Procedures ............................................................................ 298Air Sampling............................................................................................. 299

Identification of Components ........................................................... 299Tracking Sewer Gases........................................................................ 299

Sewage System Inspection Awareness ................................................300Poorly Installed Sewer Vents ............................................................300Plumbing Fixtures and Associated Traps....................................... 301In-Foundation Line Breaks ............................................................... 301Septic/Sewage Drains and Lines .....................................................302

Interpretation of Results .............................................................................302Summary.......................................................................................................303

18. Tainted Chinese Drywall .........................................................................305Health Effects ...............................................................................................306Screening Considerations...........................................................................308

Homeowner Assessment .......................................................................308Inspection Screening ..............................................................................308

Components of Chinese Drywall ..............................................................309Sampling and Analytical Methodologies.................................................. 311

Bulk Sample Collection and Analysis for Identificationof Chinese Drywall................................................................................. 311

Sample Collection............................................................................... 311Sample Analysis ................................................................................. 312

Suspect Air and Headspace Sampling for Off-GassingComponents ............................................................................................. 313

Sample Collection............................................................................... 313Sample Analyses ................................................................................ 314

Corrosion Testing.................................................................................... 315Sample Collection............................................................................... 315

Microbiological Testing.......................................................................... 316Interpretation of Results ............................................................................. 317

Chinese Manufactured Drywall........................................................... 317Off-Gassing Sulfur-Containing Gases................................................. 317Causes Corrosion .................................................................................... 318


19. Green Buildings.......................................................................................... 32121st Century Green...................................................................................... 322Green Flush-Out Protocols ......................................................................... 323

Contents xiii

LEED Indoor Air Quality Management Plan ..................................... 324ANSI/ASHRAE Standard 189.1—Construction and Plansfor Operation ........................................................................................... 324

Sampling and Analytical Methodologies.................................................. 325Interpretation of Results ............................................................................. 331Summary.......................................................................................................334References .....................................................................................................334

Glossary ...............................................................................................................335

Appendix A: Abbreviations/Acronyms.........................................................345

Appendix B: Units of Measurement ..............................................................347

Appendix C: Allergy Symptoms......................................................................349

Appendix D: Classification Volatile Organic Compounds .......................353

xv

Preface

With the new millennium comes change. Indoor air quality methodologieshave expanded, evolved, and morphed. The focus is shifting from a knee-jerkto a more proactive response. Although indoor air quality in older buildingswill continue to present old challenges, new construction is going forwardwith new challenges.

The intent of this book is to provide environmental professionals, indus-trial hygienists, and indoor air quality specialists with the latest and great-est methods in response to the knee-jerk indoor air quality challenges andfor assessing new construction prior to occupancy. The focus is to providea “practical guide” for developing a theory and following it through to theidentification and interpretation of unknown air contaminants.

Section I, “The Starting Line,” provides a historic overview with regulatorylimits and guidelines; preliminary investigation methods including meansfor assessing complaints; and a means for speculation, narrowing the huntfor offenders. With a well-defined hypothesis, the investigator must test thehypothesis by sampling. Direction is provided for determining what, when,where, and how to sample for the various airborne components that maybe found in indoor air quality situations. The components are broken intobioaerosols, chemicals, and dust.

Section II, “Omnipresent Bioaerosols,” is inclusive of microbials only. Thissection discusses sampling methodologies for microbial allergens such as fungiand pollen; invasive pathogenic microbes; and toxigenic molds/bacteria. Otherbiological components such as animal allergens are contained within anothersection.

Section III, “Chemical Unknowns and Gases,” contains sampling methodol-ogies for volatile organic compounds; microbial volatile organic compounds;carbon dioxide; carbon monoxide; formaldehyde; and product emissions.The microbial volatile organic compounds are discussed within this sectionbecause some researchers speculate that microbial (e.g., mold) by-productsmay contribute to the total volatile organic compounds in an enclosed build-ing. Yet some use the techniques to locate mold in wall spaces.

Section IV, “Identification of Dusts,” contains sampling methodologies foranimal allergens such as dust mites and forensic methods for identifyingdust components. Dust components can be checked for chemicals adsorbedonto or settled on the surface of dust particles, toxic metals, and varioustypes of fibers (e.g., resin-coated fiberglass).

Section V, “Building Systems and Materials,” is a new section. Often over-looked and underutilized, sewage gases and HVAC systems are discussedand assessment guidelines provided. The topic of tainted Chinese drywallhas become a bucket of worms—legally, financially, and analytically. In the

xvi Preface

chapter “Tainted Chinese Drywall,” the background information and moreprominent sampling methodologies are discussed. The last chapter is “GreenBuildings.” The concept of green buildings has shifted from resource con-servation only to resource conservation and healthy indoor air quality. TheLeadership in Energy and Environmental Design (LEED) Rating System andAmerican Society of Heating, Refrigerating and Air Conditioning Engineers(ASHRAE) 189.1 are discussed, and air sampling methodologies and samplelimits are detailed.

As a passion for detective work is a delightful motivator for performing anindoor air quality assessment, the person performing such a survey is hereinreferred to as the “investigator.” The investigator’s greatest asset is his or herability to weave through a convoluted web of complex problems. This bookprovides strategies and tools to herald Sherlock Holmes!

xvii

Acknowledgments

I wish to dedicate this book to those who have contributed their time andtechnical expertise to review and update technical information that isconstantly changing. A special thanks to Sean Abbott, PhD, mycologistextraordinaire and director of Natural Link Mold Lab, for reviewing theextensive section on bioaerosols. Paul Pope, MS, analytical chemist for ALSLaboratory Group, made whole the table on EPA air monitoring method-ologies, reviewed “Green Buildings”, and shared his company’s uniquefindings regarding tainted Chinese drywall. He truly has been an invalu-able resource of all information—established and evolving. Vince Delessiowith EMSL provided information regarding tainted Chinese drywall aswell, and Marilyn Black, PhD, with Air Quality Services reviewed theevolving chapter on “Product Emissions.” Each of these contributors hasbeen patient, withstanding my endless questions and ceaseless requestsfor data.

Last, but certainly not least, my husband has been my rock of sanity inthe final throes of a topic that changes daily. As my dog runs in circles, thehouse is in disarray, and the world races on, I offer my gratitude and heartfeltthanks to all!

xix

About the Author

Kathleen Hess-Kosa is the president/owner of Omega Southwest Enviro-nmental Consulting. In 1972, she received her bachelor of science degree inmicrobiology with a minor in chemistry from Oklahoma State University.After serving as an officer in the Air Force for three years, she returned toschool and earned a master of science degree (1979) in industrial hygienefrom the College of Engineering at Texas A&M University. Her researchinvolved an animal toxicological study and was conducted at the Collegeof Veterinary Sciences.

Hess-Kosa worked as a consultant for Firemen’s Fund Insurance Companiesuntil 1984. This was shortly after she passed the certification exam conductedby the American Board of Industrial Hygiene. During these five years,Hess-Kosa had the opportunity to become involved in a variety of uniqueindustrial hygiene and environmental concerns, including indoor air qual-ity concerns in an 800-occupant office building and information gatheringfor performing environmental site assessments and assessing waste. All thisand much more carried over to her private consulting business.

Hess-Kosa has since conducted numerous Phase I environmental siteassessments and published a book concerning the topic. She has activelypursued obscure sources of information and training to better address thecomplex nature of environmental issues, indoor air quality, and multiplechemical sensitivity. She has successfully identified sources of indoor airquality problems in more than 90 percent of the numerous investigationsperformed, and she has been instrumental in rectifying 100 percent of thescenarios. It took some time to get to this point, but some of the informationthat was collected and has been used by Hess-Kosa is presented within thisbook.

Section I

The Starting Line

3

1HistoricOverview

An estimated 1.34 million office buildings have problems with air qual-ity, and approximately 30 percent of all office employees are potentiallyexposed to the health effects of poor indoor air quality.1 More than 50 millionAmericans suffer from asthma, allergies, and hay fever. Chronic bronchitisand emphysema increased by more than 85 percent between 1970 and 1987.Close to 100,000 Americans die each year because of complications due tochronic obstructive pulmonary diseases (COPD).1 More than 50 percent ofour nation’s schools have poor ventilation and significant sources of pollu-tion in buildings, where an estimated 55 million students and school staffmembers are affected by poor air quality. Health effects are predominantlyobserved in children with asthma. In the last 15 years, a 60 percent increasein the incidence of asthma has occurred amongst school-aged children.Today approximately 8 percent of all school-aged children have been diag-nosed with asthma.

In an effort to address many of the prevailing and ever-looming issues,indoor air quality investigative methodologies are evolving. Indoor air qual-ity is complex!

Many indoor air quality situations culminate with litigation, differences inhealth impact, differences in perceived health effects, regulatory limits, andguidelines. Guidelines are being created by recognized public agencies, andinvestigators are being called upon to make decisions with minimal supportand direction. Finally, indoor air quality investigations are becoming moreproactive, part and parcel of the new “healthy” green buildings.

Evolution of Indoor Air Quality Investigations

The Environmental Protection Agency (EPA) ranks indoor air pollutionamong the top four environmental risks in America. People spend about90 percent of their lives indoors, and pollution is consistently two to fivetimes higher indoors than outdoors. The indoor pollutant levels have beenreported as high as 100 times the levels encountered outside.

Since the worldwide energy crisis in 1973, advances in energy efficiencybuilding construction have not been without a downside. In an effort toconserve fuel in commercial and residential buildings, builders started

4 IndoorAirQuality:TheLatestSamplingandAnalyticalMethods

constructing airtight buildings, inoperable airtight windows, and reducedair exchange rates.

In well-weatherized homes, the air exchange rate is 0.2 to 0.3 air changesper hour. In older, less energy efficient homes, exchange rates are as high as2 changes per hour. In energy efficient office buildings, air exchange ratesare around 0.29 to 1.73 changes per hour. The higher exchange rates in olderbuildings dilute and clean indoor air contaminants, whereas the newerbuildings retain them. Thus, illness associated with new buildings has cometo be referred to as “tight building syndrome.”

By 1986 the news media began to sensationalize the condition and coinedthe term “sick building syndrome.” Sick building syndrome is a conditionwhereby the occupants of a building experience health and comfort prob-lems that seem to be linked to a building, and the cause is unknown. Indoorair quality investigative methods to identify unknown sources of building-related health complaints have continued to evolve.

At the low end of the evolutionary scale, formaldehyde off-gassing fromfurnishings in office buildings and from particleboard in mobile homes wastargeted as the single most investigated culprit. One article, published in 1987,refers to formaldehyde as a “deadly sin.” New media touted, “It Could BeYour Office That Is Sick,” “Tight Homes, Bad Air,” and “The Enemy Within.”Sensational! Insurance claims were on the rise, and insurance companies beganto exclude “claims arising directly or indirectly out of formaldehyde whether ornot the formaldehyde is airborne as a fiber or particle, contained in a product,carried or transmitted on clothing contained in or a part of any building, build-ing material, insulation product or any component part of any building.”

With the passage of time it became clear that the problem was not a sim-ple one, and looking for unknowns was not a simple process. As industrialhygienists scrambled to identify other possibilities, office building investi-gations became research projects. The cost was in the thousands of dollars.Ongoing complaints recurred, and ultimately the industrial hygiene profes-sion pioneered the investigative and sampling methodologies that are inplay today.

The original hit list evolved to include not only formaldehyde but car-bon monoxide, carbon dioxide (fresh air/indicator gas), and total organics.Industrial hygienists further attempted to identify volatile organic com-pounds (VOC). Many began looking at carpet emissions (e.g., 4-phenylcy-clohexene), tobacco smoke, and airborne/surface allergens. All things werepossible. All possibilities were “open for discussion.”

In the latter part of the 20th century, residential concerns were beingaddressed with greater frequency. Considerations for sampling includedformaldehyde, carbon monoxide, carbon dioxide, allergens, electromagneticradiation, radon, and a medley of household products (e.g., VOC).

By 2000, mold became the new “hot topic.” The focus shifted from formal-dehyde and other chemicals to mold. Media headlines heralded, “The Dishon Hotel Air,” “Moldy Attitudes on Indoor Air Need a Good Scrubbing,”

HistoricOverview 5

“The Good, The Bad and The Moldy,” and “Fungal Sleuths.” The shift wasphenomenal. In the public’s eye, mold had become the single most cause ofindoor air quality complaints. This was a little shortsighted, yet it was theperceived reality. Requests to perform indoor air quality studies were equiv-alent to a “mold study” even when it wasn’t visibly apparent. Many in thepublic had turned a blind eye to other possibilities.

In many cases, when the elusive mold blame game failed and complaintspersisted, investigators were forced to revert back to the basics and carpetemissions. Yet even today very few investigators go the extra mile of spend-ing the extra money to identify VOC components and to consider other pos-sibilities (e.g., forensic dust and fine particles). Other considerations becameemissions from copy machines, sewer gases, ozone, and outdoor air. The lat-est concern has been tainted Chinese drywall.

In the 21st century, “green buildings” have become the focus. Althoughenergy and resource conservation were the primary concern, healthybuildings began to take on a whole new complexion. Green buildings arebecoming synonymous with healthy buildings. Product emissions testingand green certification of products has raced to the forefront, beginningto parallel green building concerns, and indoor air quality standards forhigh-performance (e.g., office) buildings have been proposed as of 2009.

The wave of the future is for buildings to be assessed as a unit. Buildingsystems and materials are seen as a total package. The swath of complexitiesis great. Indoor air quality challenges are many, and guidelines are beingdeveloped. The future is now!

Litigation

Managing indoor air quality has become one of the more demanding chal-lenges facing school administrators and potentially office facility managers.Legal action, negotiation, and arbitration have redefined what is consideredas acceptable. An acceptable response to indoor air quality complaints thushas come to be defined in terms of reasonable standard of care.

If a student or faculty member initiates an indoor air quality claim againsta school, the person must establish certain facts. First, the claim must dem-onstrate that the school has a duty to protect faculty from reasonably fore-seeable harm. Second, after having demonstrated the existence of a duty, theclaimant must demonstrate that the school failed to provide a reasonablestandard of care. This constitutes negligence. For example, if a staff mem-ber reports building-related health symptoms, and the administrators fail toshow a reasonable standard of care, ignoring the complaint would constitutea clear failure to show reasonable care. Third, the breach must be directlyrelated to the harm claimed. Recently the term sick building syndrome has


come to mean that a building is causing health problems, and the source isunknown.2

In the court case of Dean H.M. Chenensky et al. v. Glenwood Management Corp. et al., there is a pending lawsuit involving $180 million regarding moldexposures. In another case, Robert E. Coiro et al. v. Dormitory Authority of the State of New York, the plaintiffs are seeking $65 million. Other suits involvingvarious indoor air quality allegations are ongoing.

Thus, the driving force in indoor air quality investigations has become fearof litigation. The cost of a thorough indoor air quality investigation is smallas compared to the cost of litigation.

Differences in Health Effects

The health effects of poor indoor air quality are dependent upon several fac-tors. Relevant considerations when determining potential health effects on apopulation are the effect of each air contaminant, concentration, duration ofexposure, and individual sensitivity.

The air contaminant may be an allergen, or it may be a carcinogenic chemical.The allergen will cause an immediate reaction with minimal long-term effects.A carcinogenic chemical may not have any warning signs of exposure but maycause cancer years after exposure. It may be an irritant with passing healtheffects, or it may be a sensitizing chemical (e.g., isocyanates) whereby futureexposures may result in an extreme immune response. Indoor air generallyconsists of a complex medley of substances that may have one or a combinationof effects, and those substances that have the same health effect may not sin-gularly cause health problems, whereas two different substances (e.g., irritants)may significantly impact human health when present at the same time.

Proper diagnosis is of course dependent upon proper identification of allcontributing components. Then, once the contaminants have been identified,concentration should be ascertained.

Although there are known concentrations for many air contaminants atwhich well-defined health effects become evident, exposure levels definingthe more subtle health effects are not as well-researched. Furthermore, of theestimated 100,000 toxic substances to which building occupants are poten-tially exposed, fewer than 400 recommended exposure limits exist for indus-trial chemicals. The Occupational Safety and Health Administration (OSHA)regulates industry and EPA regulates outdoor ambient air quality. Currently,no regulatory agencies control indoor air quality exposure limits.

Exposure duration is of particular concern in assessing indoor air qualityexposures. In office buildings, exposures are generally 8 to 10 hours a day,five days a week. In residential structures, exposures may be up to 24 hoursa day, seven days a week. As some substances build up in the body over

HistoricOverview 7

time, 24-hour exposures may result in an accumulation with the subsequentimpact on health effects. Thus, the impact of a given concentration of aircontaminant is less in office buildings than in residences. Other areas thatshould be considered potential long duration exposures include hospitalpatient rooms, hotels, mental wards, and prison cells.

Individual sensitivity contributes a huge variable to the combination offactors affecting the health of building occupants. Infants, elderly people,and sickly people are the most vulnerable to the health effects of air contami-nants. Immune-suppressed individuals (e.g., AIDS patients and organ trans-plant recipients) and those with genetic diseases (e.g., lupus erythematosus)are particularly sensitive to common molds. Individuals who drink alcoholin excess are more susceptible to air contaminants that may affect the liver.People with dry skin are more susceptible to further drying and skin pen-etration by chemicals. Those who smoke tobacco products have diminishedbody defense mechanisms. Certain medications enhance the effect of envi-ronmental exposures. Individuals with predisposed conditions (e.g., lungsdamaged by fire) may have a heightened response to air contaminants.

A Misguided Premise

As they compare the indoor to industrial environments, traditional indus-trial hygienists see the good, the bad, and the ugly. The indoor air qualityenvironment is the good, and industrial environments are the bad and ugly.This is a misguided premise that requires comment.

Indoor air quality exposures involve multiple exposures to unknown sub-stances in enclosed environments often with minimal fresh air, no exposureduration limits, and a wide range of individual susceptibility. Industrialexposures involve limited exposures to known chemicals in work environ-ments with local exhaust ventilation, limited exposure duration, and healthyadults. The indoor environment does not begin to compare to the dirt andgrime of industry. Yet clearly there are differences.

A tight building has multiple factors that can result in sick building syn-drome. An enclosed environment does not mean clean air.

Regulations, Requirements, and Guidelines

Currently, federal regulatory limits for indoor air quality are limited. U.S.government directives are limited in scope. The EPA Ambient Air QualityStandards are limited to outdoor environmental pollution, and OSHA


mandates are limited to industrial pollution. Yet these regulated limits havebeen found inadequate or marginal at best in responding to cases involvingindoor air quality.

In an effort to stem the tide of indoor air quality health complaints, variousrecognized public contributors have recommended guidelines. Regulatorystandards are mandated and guidelines are recommended. The recom-mended guidelines are more apt to appropriately address indoor air qualityproblems than are regulatory standards.

Guidelines are developed, reviewed, and updated by professional expertsand are frequently cited. Formal guidelines of national importance are theAmerican Conference of Governmental Industrial Hygienists (ACGIH)and the American Society of Heating, Refrigerating and Air ConditioningEngineers (ASHRAE), and there are some international contributors.

U.S. Government Directives

A limited number of federal agencies have been given directives to considerindoor air quality in their standards. In 1994, the Department of Energy wasdirected to consider the impact of energy efficient options on habitability andpeople, and to achieve a balance between a healthy environment and energyconservation.3 In 1997, the Department of Housing and Urban Developmentpromulgated standards for the construction and safety of manufacturedhousing that includes features related to indoor air quality.4

EPA National Ambient Air Quality Standards

The EPA air quality focus is to protect human health outdoors in the ambi-ent air. The principal program that may be of some value to the reader isthe National Ambient Air Quality Standard. The intent of this standard isto control emissions of six pollutants and their precursors when released inlarge quantities (e.g., vehicle exhausts and industrial emissions). This stan-dard may be applied in indoor air quality investigations where the outsideair may potentially contribute to exposure levels indoors, such as in largenonattainment cities. Nonattainment means the city does not comply withone or a combination of the air quality standards as set forth in Table 1.1.Where exceeded outdoors, the National Ambient Air Quality Standards arelikely to be exceeded indoors as well.

Nonattainment areas are generally around large cities (e.g., Los Angelesand New York City) and industrial areas (e.g., New Jersey), but nonattainmentsites are sometimes encountered in unpredictable, isolated areas. They aredesignated by state and county, and the regional EPA office can provide thelatest information upon request.

HistoricOverview 9

OSHA Workplace Standards

OSHA claims jurisdiction over all workplace environments. The work-place includes indoor air quality exposures in office buildings as well as inindustry and construction. Yet when it comes to indoor air quality, OSHAcapabilities are limited in that the contaminants must be known and per-missible exposure limits are based on outdated limits published by ACGIHin 1968.

TABLE 1.1

National Ambient Air Quality Standards (NAAQS)

Pollutant Primary Stds. Averaging Times Secondary Stds.

Carbon monoxide 9 ppm (10 mg/m3) 8-houra none35 ppm (40 mg/m3) 1-houra none

Lead 1.5 µg/m3 Quarterly average same as primaryNitrogen dioxide 0.053 ppm (100 µg/m3) Annual (arithmetic

mean)same as primary

Particulate matter(PM10)

revokedb — —

150 µg/m3 24-hourc —Particulate matter(PM2.5)

35 µg/m3 Annuald (arithmeticmean)

same as primary

24-houre —Ozone 0.08 ppm 8-hourf same as primary

0.12 ppm 1-hourg same as primary(Applies only in

limited areas)—

Sulfur oxides 0.03 ppm 24-houra — 0.14 ppm 3-houra 0.5 ppm (1300 µg/m3)

a Not to be exceeded more than once per year.b Due to lack of evidence linking health problems to long-term exposure to coarse particle

pollution, the agency revoked the annual PM10 standard in 2006 (effective December 17, 2006).c Not to be exceeded more than once per year on average over three years.d To attain this standard, the three-year average of the weighted annual mean PM2.5 concentra-

tions from single or multiple community-oriented monitors must not exceed 15.0 µg/m3.e To attain this standard, the three-year average of the 98th percentile of 24-hour concentrations

at each population-oriented monitor within an area must not exceed 35 µg/m3 (effectiveDecember 17, 2006).

f To attain this standard, the three-year average of the fourth-highest daily maximum 8-houraverage ozone concentrations measured at each monitoring station within an area over eachyear must not exceed 0.08 ppm.

g (a) The standard is attained when the expected number of days per calendar year with maxi-mum hourly average concentrations above 0.012 is <1, as determined by Appendix H. (b) Asof June 15, 2005, the EPA revoked the 1-hour ozone standard in all areas except the 14 8-hourozone nonattainment Early Action Compact (EAC) areas.


Not only are most OSHA limits easily attained in indoor air quality inves-tigations, but there are no provisions for low-level irritants, molds, and aller-gens. Those investigators who do insist on applying the OSHA standards inoffice environments will generally find a dead-end street. These same inves-tigators often state that the OSHA standards have been met so there must notbe a problem. In a building where 80 percent of the occupants have healthcomplaints, a statement that infers the only problem is mass hysteria willmost assuredly find the investigator’s credibility questioned. The originalOSHA exposure limits were derived from the 1968 ACGIH recommenda-tions. Limits for only a handful of chemical contaminants (e.g., asbestos andbenzene) have since been updated. For this reason, most industrial hygien-ists consider OSHA limits outdated and opt to use the ACGIH guidelines.Although backed up by the force of federal law, the OSHA limits are rarelyexceeded in office environments where one or more of the contaminantshave been properly identified. The complex nature of indoor air quality isnot supported by OSHA limits.

ACGIH Workplace Guidelines

The American Conference of Governmental Industrial Hygienists (ACGIH)is a professional society of scientists that annually reviews and recommendsguidelines to industrial hygienists for use in the assessment of occupationalworkplace exposures.

The American Conference of Governmental Industrial Hygienists(ACGIH) limits are intended for use in the practice of industrial hygieneas guidelines or recommendations in the control of potential workplacehealth hazards and for no other use. … These limits are not fine linesbetween safe and dangerous concentrations nor are they a relative indexof toxicity. … A small percentage of workers may experience discomfortfrom some substances at concentrations at or below the threshold limit,and a smaller percentage may be affected more seriously by aggrava-tion of a pre-existing condition or by development of an occupationalillness.

There are around 400 chemicals listed with recommended 15 minute and8-hour exposure limits. These guidelines were created to address exposuresin the workplace. Occupational exposures are generally limited to 8-hourexposure durations for healthy adults between the ages of 18 and 65. Thus,the ACGIH exposure guidelines do not apply to residential exposures wherethe exposure parameters differ. ASHRAE has addressed this consideration.

ASHRAE Criteria for General Public5

In 1981, The American Society of Heating, Refrigeration and Air Conditioning(ASHRAE) introduced a revised mechanical ventilation standard that is now

HistoricOverview 11

referred to as the “Ventilation for Acceptable Indoor Air Quality Standard.”ASHRAE developed and evolved consensus guidelines to address indoor airquality in public buildings.

Consensus is defined as “substantial agreement reached by directly andmaterially affected interest categories. This signifies the concurrence of morethan a simple majority, but not necessarily unanimity. Consensus requiresthat all views and objections be considered, and that an effort be madetoward their resolution. Compliance with this is voluntary until and unlessa legal jurisdiction makes compliance mandatory through legislation.” Thisdefinition is according to the American National Standards Institute (ANSI),of which ASHRAE is a member.6

The purpose of the standard is to “specify minimum ventilation ratesand indoor air quality that will be acceptable to human occupants and areintended to avoid adverse health effects.” The health effects information andacceptable exposure limits rely on recognized authorities and their recom-mendations. Thus, the ASHRAE standard on “Ventilation for AcceptableIndoor Air Quality” has become the most commonly cited guideline forinvestigating indoor air quality in commercial and institutional facilities inthe world.

The standard is intended to provide ventilation design and maintenancepractices for air handling systems except where more stringent designspecifications apply. It should also be noted that in 1999, ASHRAE issueda disclaimer that “acceptable indoor air quality may not be achieved in allbuildings meeting the requirements of this standard.”5 The 2007 disclaimerhas been slightly altered to reflect “any tests conducted under its Standardsor Guidelines will be nonhazardous or free from risk.”6

ACGIH Guidelines Revisited in Older ASHRAE Standard

In a 1999 publication, ASHRAE recommended the investigator start withan acceptable limit of one-tenth of the ACGIH TLVs for acceptable indoorair quality.

A concentration of 1/10 TLV would not produce complaints in non-industrial population(s) in residential, office, school, or other similarenvironments. The 1/10 TLV may not provide an environment satisfac-tory to individuals who are extremely sensitive to an irritant. … Wherestandards or guidelines do not exist, expert help should be sought inevaluating what level of such a chemical or combination of chemicalswould be acceptable.7

This recommendation has not continued to the succeeding publications,but it has been referred to by the California Relative Exposure Limits (REL)for individual organic compounds. The California REL is frequently deferredto in assessing product emissions.


International Enforcement and/or Guidelines

In ANSI/ASHRAE 62.1-2007, “Ventilation for Acceptable Indoor Air Quality,”outdoor and indoor enforceable regulatory limits and nonenforceable guid-ance limits are listed in Appendix B, Table B-1, of the Standard. The Canadianmaximum exposure limits are for residences. The Environmental ProtectionAgency (EPA) and World Health Organization (WHO) limits are for indoorand outdoor exposures. All others are for outdoors environmental air orindustrial exposures only. The Canadian limits tend to be the lowest, moredifficult to attain.

ASHRAE Criteria for Residences

ANSI/ASHRAE 62.2-2007, “Ventilation for Acceptable Indoor Air Qualityin Low-Rise Residential Buildings,” is the only ASHRAE standard thataddresses residential indoor air quality, but it does not address acceptableair quality issues as do the ANSI/ASHRAE 62.1 series for office buildings.The standard merely sets guidelines to achieve acceptable indoor air qualityfor homes by ensuring minimum ventilation. Its purpose is to address onlymechanical ventilation by means of:

• Source control of moisture and other specific improvements throughthe use of exhaust fans

• Local ventilation in wet rooms to remove odor and moisture• Carbon monoxide detectors• Criteria to minimize back-drafting and other combustion-related

contaminants• Provision to reduce contamination from attached garages• Guidance on how to select, install, and operate systems

As there are no actual recommended ASHRAE standards for residences,the office building standards (ANSI/ASHRAE 62.1-2007 and 189.1) may bereferred to for guidance.

ASHRAE Criteria for High Performance Buildings

In 2010, ASHRAE published a “Standard for the Design of High-Performance,Green Buildings—Except Low-Rise Residential Buildings.” In this publica-tion, recommended air quality limits are lower than or equal to all U.S. andinternational standards.

The intent was to pave the way for more energy efficiency/resource con-servation and to provide for healthy building construction that requiresindoor air quality testing. Whereas the 1998 Leadership in Energy andEnvironmental Design (LEED) rating proposes an option to perform indoor

HistoricOverview 13

air quality testing, ASHRAE 189.1 mandates air testing after construction,prior to occupancy of high-performance (e.g., office) green buildings. Formore information and details, see Chapter 19, “Green Buildings.”

Summary

Tight building syndrome and sick building syndrome have become house-hold phrases. As indoor air quality complaints escalate, ignored healthcomplaints in public buildings are becoming the rationale for lawsuits andhomeowners are living in fear. In an effort to stem the tide, environmentalprofessionals are developing guidelines and recommendations that specifi-cally address indoor air quality.

Indoor air quality investigations have yet to be standardized, regulated,or managed with consistency. Thus, those performing these investigationsmust develop a strong knowledge base and actively pursue each new casewith the enquiring mind of a detective.

References

1. USA Today. Struggling to diagnose sick buildings. usatoday.com/life/health/generaVlhgen253.htm (July 20, 2000).

2. Hays, L. Lawsuits in the Air. American School & University. 72(10):35 (June2000).

3. Energy Conservation and Production Act, Pub. L. No. 94 385, 90 Stat. 1125(1976); 12 U.S.C. section 1701z 8 (1994); 15 U.S.C. section 787 (1994); 42 U.S.C.sections 787 790 (1994); 42 U.S.C. sections 6801 6892 (1994).

4. 42 U.S.C. section 6851 (1997).5. ASHRAE Standards Committee. Ventilation for Acceptable Indoor Air Quality.

ASHRAE Publications, Atlanta, Georgia. ASHRAE 62 (1999).6. ASHRAE Standards Committee. Ventilation for Acceptable Indoor Air Quality.

ASHRAE Publications, Atlanta, Georgia. ASHRAE 62 (2007).7. ASHRAE Standards Committee. Ventilation for Acceptable Indoor Air Quality:

Guidance for the Establishment of Air Quality Criteria for the Indoor Environment.ASHRAE Publications, Atlanta, Georgia. ASHRAE 62, Appendix C (1999), p. 17.

15

2InvestigationPlan

In 1984, the World Health Organization (WHO) suggested that up to 30 per-cent of all new and remodeled buildings worldwide experienced excessiveindoor air quality complaints.1 From 1989 to 1990, The National Institutefor Occupational Safety and Health (NIOSH) indoor air quality requestsjumped from 8 percent to 52 percent. In 1989, NIOSH completed approxi-mately 500 indoor air quality investigations and concluded that 34 percentof all sick building syndrome buildings were associated with indoor aircontaminants, outdoor air contaminants, building materials, or microbes.Fifty-two percent of the buildings had inadequate ventilation, and 13 per-cent were “source unknown.”2 See Figure 2.1. It is not clear whether the13 percent was due to an inability to identify unknown sources or due totypical office building complaints encountered in all office buildings.

Although many environmental professionals have found a typical com-plaint rate in office buildings to be 8 percent to 12 percent, one publicationclaims a normal dissatisfaction rate of 20 percent.3 Yet there is no fine linebetween typical and abnormal.

The most typical complaints encountered in all buildings are that of tem-perature (too hot or too cold) and humidity extremes (too dry). Less com-mon complaints are that of odors (e.g., cafeteria food in an executive’s office),unwanted noise (e.g., copy machine operation), and inadequate lighting. Inother instances, complaints may be linked to job-related and occasionallypersonal psychosocial stress (e.g., headaches) and poor ergonomic condi-tions. In a survey funded by the Environmental Protection Agency (EPA),20 nonproblem buildings around the United States were surveyed in orderto develop a baseline of complaints in structures not identified as sick build-ings. Data regarding specific complaints arising from buildings with “noindoor air quality problems,” falling within the 20 percent normal dissatis-faction rate, was as follows:

• Headache 19 percent• Eye irritation 16 percent• Fatigue 15 percent• Sinus congestion 12 percent


Sick building syndrome symptoms are very similar to buildings desig-nated noncomplaint, nonproblem buildings. The difference is simply in thenumber (or percentage) of complaints.

The greater “normal” is exceeded, the greater building-related sick build-ing syndrome becomes a facility management concern. Clearly, when thecomplaint rate in a 20-story office building exceeds 80 percent, there is aproblem. But what about complaints from 20 percent of the entire buildingwith 100 percent of the 15 occupants located within an isolated area of thehigh rise complaining? What about a small office of 20 occupants with fivecomplaining?

Don’t rule out sudden events! Where symptoms occur immediately,there has likely been an event or sudden release of a toxic substance intoan enclosed area. The release, occasionally referred to as the smoking gun,may or may not involve an entire building. For example, a prankster releasedmace into the air in a grocery store. Eye irritation and breathing difficul-ties with a sense of suffocation resulted in an evacuation of the entire store.This scenario led to a series of events that culminated with carbon monoxideexposures from the emergency response fire truck exhaust in front of thestore where the patrons and store employees gathered outside.

Poor indoor air quality and poor facility management response is a for-mula for disaster. Poor air quality spells poor employee moral, increasedsick days, and litigation. Many facility managers are becoming ever moreaware and wary of the need for good indoor air quality. In an Internetpublication:

According to a ground breaking Swedish study appearing in TheInternational Archives of Occupational and Environmental Health, 45%of “so-called” sick building syndrome victims — treated in hospitalclinics — no longer have the capacity to work. Twenty percent of the suf-ferers are receiving disability pensions, 25% are “on the sick-list.”4

Although the truth behind the statement remains to be seen, media gener-ated hysteria makes the article a reality. The cost of poor perceived or actualindoor air quality by far outweighs the cost of a good, sound indoor air qual-ity assessment!

InadequateVentilation, 52%

Outdoor Contaminants, 10%

Indoor Contaminants, 16%

Unknown Sources, 13%

Microbial Contaminants, 5%

Building Materials, 4%

FIGURE 2.1Source of complaints in buildings assessed by NIOSH study.

InvestigationPlan 17

An effective indoor air quality assessment involves a series of steps thatare outlined herein. Each step is a tool, and a tool is only as good as theuser. With knowledge and experience, some tools may not be necessary. Theinvestigator may choose to overlook some steps in one situation and followthem in their entirety in another. For example, an investigation initiated bycomplaints of headache and gasoline odors may require a couple of inter-views and a building walk-through in order to locate possible sources ofgasoline. No two investigations are the same!

Documents Review

Obtain and review the building layout, mechanical blueprints (if available),an inventory of activities, and an inventory of known chemicals, custodialactivities, and pesticide treatment activities. Additionally, some investigatorsattempt to obtain full architectural plans, specifications, submittals, sheetmetal drawings, commissioning reports, adjusting and balancing reports,inspection records, and operating manuals.

The building layout is a must have, particularly in public buildings. It maybe in blueprint form, or the schematic may be a fire exit plan. The latter is morelikely to be available and updated. As-built drawings are rarely kept up to date.

Mechanical blueprints for a building are rarely available, especially forolder buildings. If they are present, however, they are often outdated. Thisdocument is one of the single most important documents the investigatorwill require. An alternative backup is to have someone knowledgeable inthe mechanical operation of the building (e.g., building engineer or main-tenance) sketch which air handler supplies what areas. This same personshould also be asked to update altered as-built drawings to the best of his orher ability.

Identify each area by activity/activities. Get specific information. Forinstance, activities may include word processing and filing carbonless copypaper, legal casework, operating a blueprint copy machine, and gluing/paste-up work. The facilities personnel may or may not be able to providethis information. If not available, the activity information can be collectedduring the actual walk-through.

An inventory of chemicals should be collected wherein the potentialfor chemical exposures exists. In most public and institutional buildings,chemical information is sketchy at best. Management may either generalizesubstances as custodial cleaning fluid or copy toner, or they may be able toprovide material safety data sheets for all chemicals housed on the premises.The latter is the least likely to occur.

Relevant to the investigator during the walk-through and while develop-ing an air sampling strategy, custodial activities and schedules should be


obtained along with the type of supplies used. This may take some researchon the behalf of the facilities manager or may require the investigator toschedule interviews with the custodial personnel.

Custodial activities are an often overlooked contribution to indoor airquality because custodial personnel generally operate after hours. Yet theiractivities have been found to impact the indoor air quality significantly. Inone case, the custodial personnel used feather dusters in the office spacesand emptied their vacuum waste while in the office spaces (and wearing apaper respirator). In the morning, the office employees complained of visibledust in the light streaming through the windows.

Pesticide treatment activities are generally out of sight and out of mind.Although the scheduled peak treatment periods may coincide with com-plaints, the health effects of pesticides may be overlooked. In one case,spraying for a cockroach infestation resulted in airborne allergenic parts andpieces, a situation that could well have been avoided with roach motels.

Building a Walk-Through

The intent of the walk-through is to acquire an overview of the building andoccupant activities. A residential walk-through is considerably less compli-cated than one involving public buildings.

In public buildings, an initial walk-through should be planned and coordi-nated. Schedule the walk-through to include the occupancy periods and nor-mal building operation. This accomplishes two things. It shows response toand concern for the occupant complaints, and the building can be assessedas it is when fully operational. The investigator is less likely to overlook rel-evant considerations during peak complaint periods.

In the interest of time, some investigators scale down the initial walk-through considerably on the first visit by performing a documents reviewand assessing questionnaires. With this information, the investigator canthen develop an air sampling strategy and complete the walk-through at alater date while collecting air samples. Each investigator should be flexibleenough to revise the approach, as scenarios and conditions differ from oneinvestigative building to the next.

Occupied Areas

The investigator should have a set of floor plans (or a schematic) with all rel-evant information assessed during the documentation review. Several colormarkers may be helpful along with a pen, paper, clipboard (or binder), andflashlight. A building representative familiar with the air handling system


should accompany the investigator with a set of keys and tools, and a laddershould be accessible as well.

The general condition of the occupied spaces in a building should beassessed. Some items to look for include, but are not limited to, the following:

• Odors• Lint or soiling on carpets• Dirt on sheet vinyl and floor tiles• Dust on surfaces (e.g., desks and ledges)• Water damage stains (e.g., ceiling tiles with tealike stains)• Suspended dust in air (e.g., observed in light)• Moisture collecting on surfaces (e.g., condensation on windows)• Dirt and debris around the air diffusers• Cloth versus vinyl upholstery• Presence of homeowner air purifiers• Cleanliness of kitchen/food areas• Rotting food in office spaces and trash receptacles• Presence of plants• Wall penetrations• Peeling paint and vinyl wallpaper• Storage of chemicals

Continue to add to the list as the situation dictates. Always keep in mind, “Ifit looks out of place, it probably is!” Ignoring this old adage could culminatein an oversight. Even if an unexplained sense of something not right shouldoccur, attempt to identify the reason.

Air Handling System

An investigation of the air handling system generally requires some basicknowledge beyond the scope of this book. Such an assessment may requirethe assistance of a mechanical engineer or an industrial hygienist knowl-edgeable in HVAC systems.

Although the investigator may not be knowledgeable, air handling sys-tems are one of the single most important contributors or solutions to indoorair quality problems. Some of the more basic items to look for in a centralizedair handling unit include:

• Rust, damage, and water leaks around the exterior of the units• Condition and amount of water in the drip pans


• Appearance of a slime or fuzzy growth in or around the air han-dling unit and duct

• Condition of air filters• Filter exchange schedule logs• Adequate fresh air intake• Dirt, damage, and moisture buildup• Tools and equipment stored in an air handling unit

Between the main air handling units and the occupied spaces, many systemswill have additional conditioning/reconditioning units. As they are gener-ally in the ceiling spaces, these units are a little more difficult to access andwill require a ladder.

In the occupied spaces, the air supply should be measured and assessedas compared to the specifications. In some instances, building occupantsdamped down their air supply vents. These same individuals will often bethe ones complaining the most about poor indoor air quality. Sometimesoccupants get creative and jury-rig a cardboard diverter so the air will notblow directly onto them. In the absence of air supply measuring equipment,the investigator should minimally observe and take notes.

In cases requiring negative or positive pressure in a building, pressuredifferential should be measured. Once again this may require some out-side assistance. In hospitals, operating rooms require positive pressure, andtuberculosis patient rooms require negative pressure. In buildings withconsiderable infusion of outside air through the wall spaces, investigatorsdeeply entrenched in mold remediation are finding that delivery of positivepressure alleviates the mold problem considerably. Thus, positive/negativepressure measurements may be beneficial in some instances. For more detailsregarding HVAC systems, see Chapter 16.

Bathroom Air Exhaust

Bathrooms have their own exhausts, and they are frequently poorly main-tained. Sometimes the exhaust fan has ceased to function, the exhaust venthas been closed, or the vents are covered with debris. When the bathroomexhaust is associated with poor indoor air quality, building occupants maycomment, “The air smells like a toilet.” In some instances, the exhaust airfrom the bathrooms gets captured and entrained in the building air supplysystem, or the bathroom air is drawn out into the hallways and vicinity ofthe bathrooms where the bathrooms are not adequately exhausted.

A quick, easy method to inspect the bathroom exhausts is to observemovement of dust on vents or to hold toilet tissue to the vent. Observe thedirection of movement. If the tissue hangs down, it is a safe bet that the air isnot being exhausted. Or if air exhaust blows into the room instead of being


actually exhausted, the blower was probably installed improperly. Poordesign and installation is more common than one would like to believe.

Sewer System

Leaks in sewer systems are more difficult to address than simply track-ing sewer odors back to a bathroom. Odors can emanate from the mostobscure, elusive areas of a house and sewer gases may be overlooked forlack of knowledge for a simple how-to investigate migrating sewer odors,see Chapter 17.

Occupant Activities

Observe special activities within a building, ordinary and out of the ordi-nary. Beyond the facilities personnel interviews, the investigator may observeactivities that were not brought up in the discussion. This may involve ren-ovation projects, or commercial and industrial activities. The investigatorshould become familiar with all activities being conducted in the buildingand then determine chemical usage, direction of air movement, and localexhaust locations.

Interviews with Facilities Personnel

During the walk-through, the maintenance and custodial personnel shouldbe interviewed. Keep records of all these conversations. Information thatmay not seem relevant at the time may become important later.

Maintenance Staff

The maintenance worker that is most familiar with the air handling systemshould be interviewed. In smaller facilities, this may be one individual whomanages everything from nasty toilet odors and bats to complex electricalproblems. In the larger facilities, someone may be dedicated to HVAC man-agement. Whichever is the case, seek assistance from the person most knowl-edgeable in the system and obtain the following information:

• Location of fresh air intake, local exhaust units, bathroom vents, andcooling tower(s) (if not indicated on the blueprints/floor plans)

• Placement of air filters (e.g., air handling unit or air return grid)• Frequency of filter changes in the air handling system


• Special problems with the units• Rationale and usage of air deodorants and biocides in the air han-

dling system• Typical occupant complaints and maintenance response• Chemicals used frequently and associated health effects• Location of stored chemicals• Management of hazardous materials and/or waste• Methods and associated complaints when accessing work above

ceiling tiles• Recent renovation or construction activities• Methods and schedule for pesticide control

Although a wealthy resource of information, maintenance personnel have atendency to be overlooked all too often. Give them the opportunity to voicetheir impressions and special observations that may be relevant to the inves-tigation. This encourages cooperation and participation of behind-the-scenecontributors, and there may be some enlightened information that wouldotherwise have been unacknowledged.

Custodial Staff

Another overlooked contributor to the indoor air quality is the custodialstaff, which is out of sight, out of mind. However, custodial activities cangreatly impact the air quality of the building. Be forewarned that many areon contract and have a tendency to feel defensive when queried as to theiractivities. You may find someone who speaks impeccable English lapse into,“I don’t speak English.” The custodial staff interview should include:

• Cleaning schedule for the various areas• Type of vacuum cleaner• Frequency and thoroughness of vacuuming• Location where the vacuum bags are changed or contents dumped• Dusting procedures, frequency, and thoroughness• Chemicals used frequently and associated health effects• Location of stored chemicals• Waste management procedures and frequency

Encourage further input of information and avoid criticizing their proce-dures. The investigator’s purpose is to collect information. Recommendedprocedural changes can come at a later date.


Observation of Surrounding Areas

Observe activities outside the building. Traffic movement and peak roadusage periods may impact the indoor air quality. Identify areas where auto-mobile, truck, and forklift exhausts may enter the building. The buildingair intake or wall penetrations might be so located that vehicular exhaustcontributes to the indoor air quality.

Roof and road asphalting are generally associated with building com-plaints. Proximity to the fresh air intake should be considered, and informa-tion regarding the approximate time of day and duration of the hot as phaltoperation should be noted.

Take note of industrial and commercial activities, the location of exhauststacks, apparent visible emissions, and type of industry or commercial activ-ity. Suspect air contaminants can sometimes be associated with known pred-icable environmental contribution by industry type. For instance, a commoncontributor in commercially zoned areas may be naphtha from a dry clean-ing operation.

Whenever outside air is suspect, note prevailing wind direction, the rel-ative location of the building fresh air intake, suspect point sources, andexhaust stacks. Observe all possible mechanical and environmental condi-tions that may exasperate or contribute to the health complaints within thebuilding.

Assessing Occupant Complaints

The reason for an indoor air quality investigation is occupant complaints.Complaints are either ongoing or the focus of a baseline study. For this rea-son, an assessment of occupant complaints is the most important consider-ation when conducting a preliminary building investigation.

As individual health complaints can be biased and ambiguous, some inves-tigators choose to perform interviews only. Yet interviews can be unwieldyin office buildings with high occupancy. Thus, in high-occupancy buildings,the investigator should both administer questionnaires and conduct limitedinterviews. Follow all questionnaires with random interviews or with inter-views of select respondents.

Upon completion of the questionnaires and interviews, the purpose is toisolate, identify, and define complaint and noncomplaint areas. Noncomplaintareas are frequently overlooked by many investigators, but confirmation andclarification of these areas is important for comparison air sampling.


Questionnaires

Indoor air quality questionnaires should be designed to minimize bias, max-imize the response rate, and provide information that is useful to the inves-tigator. This is a tall order, not easy to fill.

Types of Questionnaires

As the questionnaire is to be filled out by a biased building occupant, bias isimpossible to eliminate entirely. The lingering question remains, “How do Iminimize bias?” There is no consensus in the response.

EPA and NIOSH published a one-page, open-ended questionnaire and anoccupant interview form. Responses to such a questionnaire may be as briefas, “I’m always sick” or “My doctor says I have sick building syndrome,” orit may include extensive details. When crunching numbers and assessingopen-ended questionnaires, the investigator will often encounter difficultiesweighing the responses.

Some investigators have developed their own questionnaires with a listingof specific complaints. Others develop these questionnaires with a responsescale (e.g., always, often, sometimes, or rarely). Opponents to this approachstate that symptom labels can be interpreted differently. For instance, oneperson may interpret shortness of breath to mean slow, labored breathingwhile another may feel it means rapid, shallow breathing. One way aroundthis is to define or clarify some of the symptoms. Leave space for and encour-age comments and observations. It is surprising the information an investi-gator might glean from offered information.

Questionnaire Response Rate

A 100 percent questionnaire-response rate is a pipe dream. No matter howwell-designed a questionnaire, there will be some that just refuse to or areunavailable to complete a questionnaire. In marketing surveys, a 20 percentresponse rate is considered good, but this is unacceptable in indoor air qual-ity investigations. An effort should be made to get a minimum of 80 percentreturn. It is possible!

To better design a questionnaire, the reasons for failure to respond shouldbe taken into consideration. Some of the reasons for not responding include:

• Too time-consuming• Too difficult to read• Never received it• Not present for the duration of the survey (e.g., out of office)• Lost it


• Didn’t remember to turn it in• No complaints• Fear of management reprisals

Each one of the above issues can be overcome. Create a one-page, easy-to-read form with check boxes and comment space for each section either on thefront page or on the back of the one-page questionnaire.

Color-code the questionnaires on the basis of air handling unit zones. Thisserves a dual purpose. First, colored paper is harder to lose on a desktop ofall-white paper. Second, organizing the questionnaires is easier when theyhave been color-coded.

Give the occupants enough time to fill out the questionnaires, but not somuch time as to allow them to forget or lose it. In offices where occupantsfrequently work outside the office, a week is generally enough time. In officeswhere occupants are present the entire day, a couple of hours may be suffi-cient. The timing should be worked out with management.

Either on a cover sheet or in the heading of the questionnaire explain therationale for the questionnaire and the importance of having noncomplaintrespondents along with the others. The information may also be made confi-dential between the consultant and the occupant.

Provide a time and location for the completed questionnaires. This shouldbe attainable and in close proximity to where the occupant is located ordeparts the building.

Informational Data

A well-written questionnaire can provide important or potentially informa-tive information to the investigator. The components may include, but not belimited to, the following:

• Physical location in the building• Comfort level (e.g., perceived temperature and humidity)• Odors• Health concerns thought to be associated with the building• Onset of symptoms (e.g., approximated date)• Occurrence of symptoms (e.g., early morning on a Monday)• Pre-existing conditions that might be more adversely impacted by

exposures while in the building• Occurrence of symptom relief (e.g., two hours after leaving work)• Observed unusual/suspicious activities or events


As data is more easily assessed relative to complaint areas, physical locationis a must. If reluctant to fill in this information, the respondent should bereminded of its importance and, at a minimum, provide the general area. Yetarea generalities are often inadequate and difficult to pin down. In the samelight, people who tend to not stay put in an office environment are difficult toassess. Generalities make the final assessment quite challenging.

Comfort level allows the respondent to complain without associated tem-perature and humidity concerns with health complaints. They are not oneand the same, but comfort level may enhance or reduce perceived healthproblems.

Odors are very subjective. Heavy perfume to one may be an overpower-ing stink to another. The smell of asphalt may be described by one person assweet and by another as a chemical smell. The latter description is commonfor unfamiliar odors. Whereas most people describe mold by-products asmildew, others describe it as dirty feet or like the interior of a cave. While it isdifficult to interpret odor descriptions, the information can assist the inspec-tor to glean direction as to the potential source of health complaints.

The actual health complaints should be associated with the building, not out-side activities. If providing a checklist format, offer symptoms that are easy tointerpret. For instance, the symptom of congestion may be replaced with stuffynose. Irritated skin may be replaced with dry, flaky skin or itchy, red bumps. In alisting, try to keep the description of symptoms abbreviated and to the point.

The date of onset of symptoms is difficult if not impossible to tie down.Unless they experience health effects the first time they walked into thebuilding, people do not notice they are having health problems until longafter the initial exposures. Then most of the occupants will live with it untilthey hear others expressing concerns. On the other hand, if an approximatetime period can be associated with occupant activities, building renovation,or scheduled work activities (e.g., pesticide application), a narrowing of thegap on source identification may occur.

Pre-existing health conditions or medications that might be adverselyimpacted by exposures in the building may or may not be understood by therespondent, but they can occasionally provide some valuable insights. Forinstance, someone who has anemia would be more susceptible to the healtheffects of carbon monoxide that others. Asthmatics will experience worsenedconditions when exposed to excessive airborne allergens (e.g., dust mites).

In most indoor air quality situations involving allergens in a building,the occupant will experience relief within two hours of departure. If theexposure is to carbon monoxide, relief may not be apparent for a couple days.This information can be very helpful to the investigator.

Permit the occupant some space to speculate and provide personal insight asto the source of the problem. Occasionally, occupant observations provide tre-mendous insight. It has been to the amazement of the author that people givena chance to contribute, unbeknownst to them, had the answer all along.


Interviews

When not used as the only means for gathering complaint information,interviews are where the investigator can clarify information and gain fur-ther details not obtained from the questionnaires. Unless you have a pre-conceived concern or special issue, allow the interviewees to tell you in theirown words about their concerns. Concern is a less intimidating term thancomplaints. Listen to what they say without a preconceived notion, and fol-low up with questions to get a clear focus on that individual’s concerns. If notalready covered, all the items discussed above should be discussed as well.Yet, a touch of reality, some interviewees will gladly talk all day. Set a timelimit and at some point politely move on.

Summary

Steps include a documents review, building walk-through, interview of facil-ities personnel, observation of the surrounding areas, and an assessment ofoccupant complaints. All steps may or may not be required in each differentsituation, and the components are subject to change likewise.

Keep in mind that the procedures presented herein can and should beexpanded or utilized in part. When performing a preliminary investigation,attempt to avoid preconceived notions and biases. Be prepared to seek thatwhich is intuited. An open mind is the investigator’s greatest tool.

References

1. U.S. Environmental Protection Agency. Indoor Air Facts No. 4 (revised) Sick Building Syndrome. Indoor Air Quality, EPA (April 26, 2010).

2. Hedge, A. Addressing the Psychological Aspects of Indoor Air Quality (Paper).Cornell University, Ithaca, New York (1996).

3. U.S. Environmental Protection Agency and National Institute for Occupa-tional Safety and Health. Building Air Quality: A Guide for Building Owners and Facility Managers. U.S. Government Printing Office, Washington, D.C.(December 1991).

4. Goldstein, R. Sick Building Syndrome: Floods, Mold, Cancer, and the Politics of Public Health. Organic Consumers Association. Retrieved from http://www.organic-consumers.org/articles/article_17435.cfm (May 12, 2010).

29

3TheHypothesis

The objective of an investigator is to identify and solve indoor air qualitycomplaints in a way that prevents a recurrence, not create other problems.Although this may seem an overstatement of the obvious, poorly researchedand executed investigations are consistently recurring.

In one situation, an investigator recommended increased fresh air intake.Health complaints from the occupants were reduced from 90 percent to20 percent. Another investigator convinced the building management thatthe 20 percent could be improved with a building “burn out.” The source ofthe complaints had never been identified, but the second investigator, with-out further investigation, recommended a procedure that worked in anotherbuilding. Sounds good! It should work again. The burn out involved ele-vating temperatures over a long weekend and flushing the building with100 percent makeup air. The result was 75 percent health complaints, a recur-rence of problems.

Another situation involved elevated mold spores and no diagnosticevaluation to determine the source of amplification. The investigatorspeculated that the spores were growing in the perpetually damp build-ing crawl space. The recommendation was to use powerful exhaust fansto move air through the crawl space and dry out the soil. The result wasair movement over the soil and being exhausted outside where it waspicked up by the air intake and distributed throughout the building.Health complaints worsened. The reason was an untested hypothesis,insufficient diagnostic sampling, and recommendations based on unsub-stantiated speculation.

A well-researched preliminary investigation is the best avenue to avoidsome of these pitfalls. A strong foundation of information should result ina hypothesis. Avoid assumptions! Gather information, formulate a hypoth-esis, test the hypothesis, and make recommendations. The preliminaryinvestigative process was discussed in the preceding chapter. Herein we dis-cuss putting the information in an easy-to-assess format and formulating ahypothesis.


Information Review

An easy-to-access format of the voluminous amount of data possible in per-forming an indoor air quality investigation can be daunting at best. Theauthor has reviewed many different formats and found an approach thatworks best in most instances. The methods provided are simplified andshould be expanded to suit individual needs. These assessment methods area working tool to be expanded and improved upon.

Building Assessment

The building assessment includes information gathered from the build-ing walk-through, interviews of facilities personnel, and observations ofsurrounding areas. If not simplified, the information may become a papermorass, overwhelming and confusing.

One suggested approach wherever possible is to summarize information onthe building blueprint or schematic. This may even be the ever-present fire evac-uation plan. Either take notes on the drawing during the walk-through or sum-marize important information on the drawing after compiling all the data. Ina publication regarding building assessment methods, “Building Air Quality,”NIOSH/EPA suggest this technique for assessing pollutant pathways.1

Color markers, colored pens, overlays with indelible markers, and a cod-ing system are recommended tools. Several sheets of the basic floor plansare also helpful. Summary comments may include, but are not be limited to,the following:

• Air delivery zones, based on air handling units supplying air tothat zone

• Plumbing discrepancies (e.g., leaking pipes)• Ventilation discrepancies (e.g., air supply vent closed) or observa-

tions (e.g., redirected air flow)• Unspoken comments or fixtures regarding perceived air quality

(e.g., air purifiers and pedestal fans)• Chemical storage areas• Location and type of equipment that may involve air contaminants

(e.g., copy machine)• Water damaged structural components (e.g., water damaged ceil-

ing tiles)• Lifting/poorly adhered floor tiles and sheet vinyl• Peeling paint and vinyl wallpaper• Rusted metal structural components (e.g., air vents and window

frames)

TheHypothesis 31

• Room(s) with carpeting• Stains of flooring (e.g., burned floor tiles or stained carpeting)• Bathroom exhaust discrepancies• Location of elevators and other structures that may impact air move-

ment (e.g., doors and stairwells)• Plants• Wall penetrations• Areas where investigator, not occupants, noticed odors• Location of bathrooms and custodial closets• Commercial/industrial activities in the building• Approximate direction of commercial/industrial activities outside

the building• Direction of prevailing winds• Location of break room/kitchen• Signs of infestations (e.g., cockroaches, rodents, bats, pigeons)• Local exhaust ventilation

Comment about and enter information that does not seem relevant at thetime. When assessing the relative locations of potential sources, discrepan-cies, and other observations as one, the investigator may be able to relate onepreviously disassociated item to another. See Figure 3.1.

Complaint Occupant

The single most important source of information is the occupant. With build-ing complaint input, the investigator can define the complaint area(s) and deter-mine the severity of the complaints as well as look for symptoms, occurrenceof symptoms, and perceived associations. Problem and nonproblem areas canbe identified. Problem areas may be compared to the building assessment find-ings, and a potential causative agent can be projected. There is just one factorthat complicates the process: buildings with a large number of occupants.

In a large-occupancy building, the investigator must collect a large volumeof information and reduce it to a manageable format. Color-coding question-naires (e.g., coded air handling zones) is a good start. For confidentiality,each set should also be numbered, summarized, and filed by the investiga-tor. The numbered and summarized information may then be installed intoa spreadsheet or color-coded on the floor plans. It is best to make entries inboth areas, and clarity is more apt to be gleaned from specific sites occupiedby each of the respondents. Where there are no cubicle or office numbers,a little more creative coordination is required. For an example of the sum-mary format, see Figure 3.2.


Upon completion of the complaint summary or interviews, the investiga-tor should attempt to relate the symptoms to potential sources. This mayinvolve a direct correlation, or the possibilities may be multiple.

In most sick building syndrome situations, the symptoms are allergenic innature (Appendix A) and occur only when the occupant is in the buildingand subside within a couple hours after departure from the building. As therecent trend has been to point an accusatory finger at molds, the full range ofpossibilities is frequently overlooked.

To a lesser extent there are those sick building syndrome cases beyondthe norm that involve a wider range of health effects (e.g., disease, febrile,flu-like symptoms, dermatitis, irritation, and systemic toxicity). These non-allergy health effects may be associated with a single substance, or they maybe complicated by the effect of several substances. Several different agentsmay have the same health effect and result in an accumulation of differentlow-level exposures, or they may have different health effects contributingto the overall impact. For reference information concerning health effects,causative agents, and their occurrence, see Table 3.1.

Hypothesis Development

With the completed building and complaint assessments, the investigatorcan project possible scenarios of cause and effect. Write down all probableexplanations for the complaints. Look at the noncomplaint areas as well asthe complaint areas. Look for links between the building components andcomplaints. Project sources of exposure and pathways.

One area may have several sources that may contribute to the overallhealth complaints. For instance, a carpet infested with dust mites and airsupply vents disbursing mold spores may result in allergy symptoms. If theinvestigator theorizes only the mold spores, encounters moderate airborneexposures, and remediates the air supply vents, the contributing dust miteswill be missed and remain uncorrected with a level of continued allergysymptoms.

On the other hand, different areas of one building may have differentproblems and each of these as complex as that discussed previously. Area 1may have rodent allergens and airborne fiberglass from the air duct lining,and Area 2 may have leaking (e.g., chlorofluorocarbons) and excessive levelsof carbon monoxide. Symptoms will be different in these areas. If consideredpart of a composite, the two areas will be overlooked as one. The cause andeffect may be overlooked entirely.

These scenarios are not unusual. The investigator should keep an openmind at all times. Develop a set of hypotheses. Consider the pathways andtest the hypotheses.

TheHypothesis 35

There are two ways to test a hypothesis. The easiest way is to project thesource and associated solution. Where a hypothesis projects an inexpen-sive solution and sampling is expensive, the hypothesis may be tested bymanipulating building conditions or the ventilation system. As indicated inFigure 2.1 in Chapter 2, the source of complaints in many indoor air quality

TABLE 3.1

Reference Chapters for Relating Symptoms and Source Occurrence

Allergy symptoms: associated with the building and symptoms subside within a couplehours of departure

Chapter 4 “Pollen and Spore Allergens”Chapter 5 “Viable Microbial Allergens”Chapter 14 “Forensics of Dust”Chapter 15 “Animal Allergenic Dust”

Disease: associated with a building and symptoms continue until the illness has run its courseChapter 6 “Pathogenic Microbes”

Dermatitis: associated with the building or a work product, and symptoms may improveupon removal or departure from the area but recovery may take a few days

Chapter 4 “Pollen and Spore Allergens”Chapter 5 “Viable Microbial Allergens”Chapter 6 “Pathogenic Microbes”Chapter 7 “Toxigenic Microbes”Chapter 8 “Volatile Organic Compounds”Chapter 12 “Formaldehyde”Chapter 14 “Forensics of Dust”Chapter 15 “Animal Allergenic Dust”

Eye irritation: associated with the building and subsides upon departureChapter 4 “Pollen and Spore Allergens”Chapter 5 “Viable Microbial Allergens”Chapter 7 “Toxigenic Microbes”Chapter 8 “Volatile Organic Compounds”Chapter 9 “Mold Volatile Organic Compounds and Mold Detection”Chapter 12 “Formaldehyde”Chapter 14 “Forensics of Dust”Chapter 15 “Animal Allergenic Dust”

Systemic illness: associated with the building and may subside over time after departureChapter 5 “Viable Microbial Allergens”Chapter 7 “Toxigenic Microbes”Chapter 8 “Volatile Organic Compounds”Chapter 9 “Mold Volatile Organic Compounds and Mold Detection”Chapter 12 “Formaldehyde”Chapter 14 “Forensics of Dust”


investigations had been identified in 52 percent of the study cases as inad-equate ventilation. It would be more appropriate to state that ventilation rec-tified the problem, not that it was the problem.

Sampling is a more direct approach to proving a hypothesis, and is theonly method whereby the investigator can definitively clarify the source orsources of occupant complaints. As with a medical doctor who develops ahypothesis as to an illness, the only way he can definitively prove the causeof the illness is to perform a series of tests. To properly treat an illness thedoctor must identify the appropriate tests that will provide the much neededinformation. If the diagnosis is incorrect, treatment of symptoms may or maynot work. It is, likewise, preferable in indoor air quality that the hypothesisbe tested, proven, and acted upon appropriately.

The Proactive Approach

In order to minimize the sampling and effectively target potential sourcesof indoor air quality complaints, the investigator would be best served byhaving performed a baseline walk-through of the same building when therewere no complaints. The recently published ANSI/ASHRAE Standard 189.1requires postconstruction air monitoring and an ongoing means to assessindoor air quality complaints.

A proactive survey involves a scaled down variation of the more in-depthinvestigation that results from health complaints. The upfront costs aregreater, but the end result pays off in dividends.

Develop a plan for preventing poor air quality. This plan should include,but not be limited to, the following:

• A means whereby complaints are addressed in a timely fashion• A guide for determination of an excessive number of complaints in a

building or area of a building• A means for maintaining records of building complaints, activities,

and renovations• A response action

Establish a baseline of occupant concerns and a building profile. A baselinetaken in a healthy building will provide valuable information should thefacilities manager or investigator determine that the building has an inordi-nately high number of health complaints.

Perform a limited amount of air sampling. This should be kept at a mini-mum while providing data regarding contaminants that may be reasonablyimplicated in future concerns.

TheHypothesis 37

Steps include a walk-through of a facility, an assessment of occupant com-plaints, identifying problem niches, assessing the building, assessing activi-ties associated with the building, and compilation of all the data. Makingsense of the mass of information collected is the investigator’s greatestchallenge.

Beyond the Scope

There are literally hundreds and thousands of substances that go beyondthe scope of a single textbook. Other areas of expertise that may be requi-red include medical physicians, industrial hygienists, toxicologists, andpsychiatrists.

Medical Physicians

Medical physicians can address special situations involving individualsthat are particularly susceptible to various environmental agents, and theycan perform some speculative testing of occupants to determine susceptibi-lity. Some examples are of susceptible individuals are immune-suppressedpatients, individuals that are anemic, and asthmatics. The boy that lived ina bubble had no immune system to speak of. Were he to be exposed to thesame environment as others he would surely die.

Prescription and over-the-counter drugs can also affect one’s reaction toenvironmental influences. If while taking an allergy medication that causesone to become drowsy an individual is exposed to low levels of a chemicalnarcotic, the effect can be enhanced.

Speculative testing is not the ideal approach to indoor air quality situa-tions, but it is applicable in some situations, particularly where there areno known environmental sampling methods readily available for testinga hypothesis. In a hospital, a group of people experienced allergy symp-toms when working in an area where latex gloves were frequently changed.Upon performing latex allergy testing on some of the people, the physicianwas able to confirm latex sensitivities in those with the greatest number ofcomplaints.

Occasionally, a person claiming to have multiple chemical sensitivity maybe one of the building occupants. The mere uncapping of a magic marker willelicit a reaction. Perfumes and deodorants are intolerable. They cannot go toa gasoline station for fuel without special respirators. If one of these individ-uals is a respondent to an indoor air quality questionnaire, the response willlikely be dissimilar to the others. Generally, these people will have soughtdiagnosis by a physician.


Industrial Hygienists and Toxicologists

Industrial hygienists are trained and experienced in the anticipation, recog-nition, evaluation, and control of health hazards. Some of the less frequentlyencountered indoor air quality issues involve substances that are beyond theabilities of an untrained individual to assess. These substances include met-als and pesticides/insecticides.

Some of the metal exposures that may be considered in indoor air qualityare airborne lead, mercury, and arsenic. This may appear simple on directanalysis, but an assessment must be made on the basis of the form a metalis in and the environment. For example, Scopulariopsis bevicaulis growingon wet copper arsenite pigment wallpaper will produce trimethoxy arse-nic vapor. Arsine gas is evolved when arsenic compounds react with acids.2These different forms of arsenic would require different sampling method-ologies, and this applies likewise to the other metals.

Misapplied pesticides can have adverse, sometimes life threatening effectson individuals. One of the most commonly sampled pesticides indoors isthe banned termiticide chlordane. Although banned from use in the UnitedStates, DDT is still encountered in the environment and continues to be usedin Third World countries.

Industrial hygienists and toxicologists stay current with publications onrecent findings in research that is not covered by the media. Of import toindoor air quality is a recent hazard review on carbonless copy paper. It wasfound that some types of carbonless copy paper result in symptoms of skin,eye, and respiratory tract irritation; allergic contact dermatitis; and someunclear systemic reactions. Although the chemical agent has yet to be identi-fied, the relationship was indicated through epidemiological studies.

In another case, occupants complaining of dermatitis on the back of theirthighs all sit on fabric upholstered chairs. The chairs are found to be allergenfree. Yet it is noted that custodial staff members use a strong disinfectant forcleaning the chairs. This is a case of guilt by association.

Psychiatrists

This is the skeptic’s corner, the last recourse for finding the cause of sick build-ing syndrome. As cases go unsolved, investigators turn more and more to per-ceived indoor air quality on the basis of physical, psychological discomfort,and odors. Then, too, there is mass psychogenic illness (MPI), or mass hysteria.

Mass psychogenic illness refers to “the collective occurrence of a set ofphysical symptoms and related beliefs among two or more individualsin the absence of any identifiable (cause).” Social psychological processesof contagion, where complaints and symptoms spread from person toperson, and convergence, where groups of people develop similar symp-toms at about the same time ... Environmental events, like an unpleasantodor, can trigger contagion and convergence processes, and occupants

TheHypothesis 39

who cannot readily identify what has triggered their symptoms oftenattribute these to any visible environmental changes, such as installationof a new carpet, or invisible agents, such as “mystery bugs.” MPI symp-toms include headache, nausea, weakness, dizziness, sleepiness, hyper-ventilation, fainting, and vomiting, and occasionally skin disorders andburning sensations in the throat and eyes.3

Summary

Upon completion of a preliminary investigation, the information shouldbe compiled and simplified. Otherwise, the investigator may become over-whelmed and may not be able to see the forest through the trees.

The building and occupant assessments should be critically reviewed anda hypothesis developed. The hypothesis may involve one or several potentialsources, and it may be complicated by the existence of one or several disassoci-ated areas. Too often this point is overlooked. Recommendations to remediateone of several problems may result in unsatisfactory results. The objective is toopen the door to all possibilities, to limit the amount of testing required to provea hypothesis, and to appropriately target identifiable, quantifiable sources.

The most direct approach to proving a hypothesis is sampling. Samplingmay involve one, or a combination of, screening, air sampling, and diagnostictests. Yet even the testing may result in incomplete, inconclusive informationif not performed properly. There have been instances whereby an untrained,uninformed investigator has taken expensive samples where strategy wasnot considered, sampling methodologies were inappropriate, and interpre-tation was limited. It is the purpose of this book to provide direction forsampling some of the more commonly encountered substances in sick build-ing syndrome. See Table 3.1 for suggested chapters for directions to makingsampling decisions.

References

1. U.S. Environmental Protection Agency and National Institute for OccupationalSafety and Health. Building Air Quality: A Guide for Building Owners and Facility Managers. U.S. Government Printing Office, Washington, DC (Dec. 1991), p. 70.

2. Kaye, B.H. Science and the Detective. VCH, New York (1995), p. 9.3. Hedge, A. Addressing the Psychological Aspects of Indoor Air Quality (Paper).

Cornell University, Ithaca, New York (1996), p. 3.

Section II

Omnipresent Bioaerosols

43

4PollenandSporeAllergens

They are everywhere! Except in the most restrictive of environments (e.g., anenvironmentally controlled, filtered bubble enclosure), allergens are every-where, and the most commonly recognized allergens are pollen grains andfungal spores.

Pollen grains are the male reproductive cells that are dispersed by plantsto fertilize the female flower of the species. They are typically outdoor aller-gens but have on occasion been found to be problematic due to the captureand retention of the pollen within an air system.

Spores, as presented herein, are to include all forms of fungal spores (e.g.,mold spores and mushroom basidiospores). Fungal spores are reported toaffect more than 20 percent of the adult population. It should be noted, how-ever, that some bacteria may also produce spores, and these are discussedmore fully in Chapter 5.

Pollen grains and spores must be airborne in order to cause respiratoryallergy symptoms, and the total exposure to all of these will have a varyingaffect on those exposed. The higher the exposures, the greater the numberof people affected. Their impact is irrespective of viability, or their ability togrow. Dead molds do not go away. They merely stop reproducing and grow-ing. Mold spores persist—dead or alive!

Occurrence of Pollen and Spore Allergens

Pollen grains are the male reproductive cells that are dispersed by plantsand carried by insects, animals, and wind to fertilize the female flower oflike species. Those that are carried by insects and animals tend to be sticky,possess an elaborate exterior surface (e.g., spines and heavy ridges), and arelarge by comparison to the other pollen grains (e.g., up to 250 microns insize). On the other hand, those that are dispersed by wind tend to be non-sticky, smooth, light in density, and small in size (e.g., generally less than50 microns). These reproductive cells are produced by weeds, grasses, andtrees. There are more than 350,000 species of plants. Plants are geographicand pollen production (i.e., pollination) is seasonal.

Fungi include single celled yeasts, filamentous molds, and multicellularmushrooms. Possessing a hard chitin or polysaccharide exterior covering,


fungal spores are typically resistant to drying, heat, freezing, and somechemical agents.

General Information

Allergenic spores and pollen may be transported by high winds as far as1500 miles, and it is possible to find them 100 miles from their point of ori-gin.1 If one were to draw a contour map showing levels at various pointsfrom a source, it would be evident the highest concentrations are close to thesource, diminishing with distance and impacted by wind direction, velocity,and volume of pollen produced at the source.

Small fungal colonies may discharge as many as 30 billion spores per day.Pollen grain discharges may be likewise remarkable with numbers reportedas high as seven trillion pollen grains per tree on a season. See Table 4.1.

Attempts have been made to identify allergenic pollen types and the timesof the year when their local presence is increased. Some highly allergenicindividuals make decisions for relocation based on the prevalence of givenallergens. Although Table 4.2 demonstrates an effort to categorize by state,the determinations are generalized and may not be representative of localareas within the regions mentioned.

The size, shape, and density of the airborne allergens affect their aero-dynamic properties, while the air humidity, wind direction, wind veloc-ity, and obstructions affect their travel path as well as their travel distance.Temperature, soil types, and altitude may also impact the quantity of air-borne allergens.

The size of fungal spores range from 1 to more than 500 microns in diameter/length, but those that are typically airborne range in size from 1 to 60 microns.

TABLE 4.1

Pollen and Spore Single Source Discharge Rates

Fungal Spores—One Colony or Growth Unit

Ganodenma applanatum 30 billion per day Daldinia concentrica 100 million per day Penicillium spp. 400 million per day

Pollen Grains—One Tree

European beech (Fagus sylvaticus) 409,000,000 per year Sessile oak (Quercus petraea) 654,400,000 per year Spruce (Picea abies) 5,480,600,000 per year Scotch pine (Pinus sylvestris) 6,442,200,000 per year Alder (Alnus spp.) 7,239,300,000 per year

Source: From Smith, E.G. Sampling and Identifying Allergenic Pollens and Molds: An Illustrated Identification Manual for Air Samplers.Blewstone Press, San Antonio, Texas (1990). With permisson.

PollenandSporeAllergens 45

TABLE 4.2

Plant Allergens by Region

Northern WoodlandTrees (April–June)—birchFungi (June–October)—mushrooms and puffballs; watertight cabins and cottages tend to bemoldy

Eastern AgriculturalTrees (March–May)—ash, birch, box elder, elm, mulberry, oak, sycamore, and walnutGrass (May–July)Weeds (July–September)—hemp, goosefoot, and ragweedFungi (May–November)Other—castor beans, cottonseed, and soybeans

Southeastern CoastalTrees (February–April)—ash, elm, oak, pecan, and sycamoreGrass (February–October)Weeds (July–October)—ragweedFungi (all year)

Southern FloridaTrees (January–April)—oakGrass (January–October)Weeds (June–October)—ragweedFungi indoors (all year)

Great PlainsTrees (February–April)—oakGrass (April–September)Weeds (July–October)—goosefoot, ragweed, and sageFungi (May–November)Other—livestock dander, fertilizer dust, animal feed dust, grain, and storage dust

Western MountainTrees (January–March)—mountain cedarGrass (May–August)Weeds (July–October)—goosefoot, ragweed, and sage

Great BasinWeeds (July–September)—goosefoot and sage

Southwestern DesertTrees (January–April)—Arizona cypress, mountain cedar, and mulberryGrass (March–October)Weeds (April–September)—goosefoot and ragweedFungi (increased by use of evaporative cooling units in buildings)

California LowlandGrass (March–October)


The Cladosporium mold spores typically range between 4 and 20 microns inlength. Alternaria spores are around 30 microns in length (ranging from 8 to500 microns), and Aspergillus/Penicillium spores are around 1 micron in diam-eter. It should be noted that some spore-producing bacteria are also on theorder of 1 micron in size and may appear microscopically to be mold sporesand cannot be differentiated without growing the spores in nutrient agar. SeeFigure 4.1 for differentiation between two molds of similar spore production.

Pollen grains are typically denser and, on the average, larger in size than thefungal spores. They range from 14 microns (for stinging nettle) to more than100 microns in diameter. Tree and weed pollen are the more variable. Most, how-ever, fall between 20 and 60 microns. Red cedar and Western ragweed pollenare on the low end, around 20 to 30 microns. Scots pine and Carolina hemlockare between 55 and 80 microns. Cedar pollen is around 30 microns in diameter.Giant ragweed pollen grains are around 18 microns in diameter, and Noble Firpollen is around 140 microns. See Figure 4.2 for representative types.

Fungal spores are in the form of spheres, ovals, spirals, elongated stellates(star-shaped), and clubs. They may be elongate, chained, or compact and,generally, the surfaces are smooth. See Figure 4.3 for some shape differentiat-ing features. They lack hairs, spicules (needles), and ridges, features commonto pollen grains, which are more complicated in design.

Pollen grains tend to be spherical or elliptical with surface structures and/or pores, and the interior portions typically have a recognizable arrange-ment. They may be lobed with a smooth surface or spherical with spicules.Their interiors may be thick walled, undifferentiated or thin walled, or

FIGURE 4.1Differentiation between molds starts with the microscopic appearance of colonies and associ-ated spores. This example demonstrates the spore-producing structures of two different gen-era of fungi that have similar size and shape spores. Both are around 2 to 3 microns in diameterand are beadlike in shape.


FIGURE 4.2Representation of allergenic plants and pollen categorized into trees [e.g., cedar (a)], grasses(e.g., tall wheat (b)], and weeds [e.g., giant ragweed (c)]. The examples shown above are amongstthe more allergenic within their category. Photomicrograons courtesy of Sean D. Abbot, PhD,Nature Link Mold Lab, Rerio, NV.


(b)

(c)

(d)

(e)

(f)

(a)

FIGURE 4.3Cladosporium (a), Alternaria (c), and Penicillium (e) are among the more commonly encounteredmold spores in the outdoor air environment. The sketches (b), (d), and (f) are relative size com-parisons of the respective spore types. Photomicro graphs courtesy of Sean P. Abbott, PhD,Natural Link Mold Lab, Reno, Nevada.


multifaceted. Ragweed pollen is spherical with multiple spines, and pinepollen grains are lobed with a smooth surface.

Plant pollen is generally more complicated in design than are the spores.They tend to be spherical or elliptical with surface structures and/or pores,and the interior portions typically have a recognizable arrangement. Theymay be lobed with a smooth surface or spherical with spicules. Their inte-riors may be thick walled, undifferentiated or thin walled, multifaceted.Ragweed pollen has a spherical morphology with multiple spines. The pinepollen is lobed with a smooth surface.

Pollen densities range from 19 to 1003 grains per microgram. Hickory pol-len is moderate in size, weighing in on the low end of the scale. Giant rag-weed and nettle, even though small in size, are on the high end in density.

Spore-Producing Fungi and Bacteria

Both fungi and fungilike bacteria produce allergenic spores. Although themost commonly encountered spores in indoor air quality are mold spores,other fungal spores and bacterial spores can and frequently do contribute tothe total airborne spore count.

Fungi

Fungi, numbering more than 100,000 different species, are neither plant noranimal. Lacking in chlorophyll (plantlike) and typically not motile (an ani-mal characteristic), they belong to a kingdom of their own. The fungi king-dom consists of molds, yeasts, and mushrooms rusts, smuts, slime holds, andyeasts. Where the yeasts are single-celled organisms, molds grow into long,tangled strands of cells that multiply, forming visible colonies of varyingsizes, shape, texture, and diameter. Some fungi form complex fruiting bod-ies that are composed of tightly compacted masses of moldlike filaments andare clearly visible to the naked eye. (e.g., mushrooms).

Molds

Mold spores are the most commonly referred to fungi. Their cell wall and pro-tective spore surface is composed of polysaccharides (e.g., cellulose) and glucoseunits containing amino acids (e.g., chitin). The cellulose component is plantlike,and the chitin component is animal-like. It is the outer protective surface of themold, spores and growth structures that is thought to be that which elicits anallergic reaction. For this reason spores are generally implicated in most allergyconditions, sections of the growth structures can be allergenic as well.

Mold reproduction involves the release of thousands of allergenic spores,each having the ability to reproduce long, threadlike hyphae that continueto branch and form mycelia. The mycelium, in turn, attaches to a nutrientsubstrate and grows. As long as the mycelium has nutrients and room to


grow, a single mycelium may theoretically expand to a diameter of 50 feet.See Figure 4.4 for diagram of mold structures.

Specific mold genera are reputed to provoke allergylike symptoms moreconsistently than others. This may be due to the challenge by shear numbersof a given species, or it may be due to one species being able to elicit a stron-ger reaction than another. See Table 4.3. It is not clear as to which is the case.

Aerial hyphae

Subsurface hyphae

Spores

Germination

Mycelium

Mycelium

FIGURE 4.4Typical mold structures.

TABLE 4.3

Mold Spores (in Alphabetical Order)Reported to Provoke Allergy Symptoms

Acremonium spp.2 Fusarium spp.4

Altemaria spp.2–5 Helminthosporium spp.5

Aspergillus spp.2–5 Mucor spp.4

Aureobasidium pullulans2 Nigrospora spp.4

Aureobasidium spp.4 Penicillium spp.2–5

Chaetomium spp.4 Phoma spp.4

Cladosporium spp.4 Rhizopus spp.4

Drechslera spp.2, 4 Scopulariopsis4

Epicoccum spp.4 rust molds and smuts5


Molds not commonly known to cause an allergic reaction may also contrib-ute to the overall response of an individual’s immune system to those moldsthat are reported to provoke allergy symptoms. Then, too, some authori-ties believe that individuals can develop an allergy to nonallergenic fungior become sensitized to a fungal spore that is not commonly a problem formost people. Generally, however, allergenicity is genus or species specific.An allergic reaction to one mold type does not necessarily follow that thesame will occur with another.

The most common airborne spore is Cladosporium. Beyond Cladosporiumthere is some variation, based on geographic region and the time of the year.The consensus appears to be for Alternaria as the second-largest contributor,and many include Aspergillus and Penicillium. Ironically, most of these moldsare reputed causative allergenic agents for most mold-sensitive patients.Table 4.4 provides percents of total airborne mold spores reported by onesource to represent the most common airborne allergenic molds. Most find-ings include many of the same genera with a slight variation on percent,based on regional differences.

A single colony is capable of dispersing millions of spores in one day. SeeTable 4.5. The spores are shot out of their capsule or dislodged from theirstalk and carried by the wind to be spread far and wide. Spores (and pollen)

TABLE 4.4

Most Common Airborne Allergenic Molds from 19 Random Surveys

Genera Prevalence (%) Natural Habitats

Cladosporium 29.2 Worldwide: soil, textiles, foodstuffs, andstored crops

Region dependent: woody plants (e.g.,straw) and paints

Alternaria 14 Worldwide: decaying plant matter,foodstuffs, soil, and textiles

Penicillium 8.8 Region dependent: soil, decaying vegetation,foods, cereals, textiles, and paints

Occasional occurrences: compost piles,animal feces, paper/paper pulp, storedtemperature foods, cheeses, and rye bread

Aspergillus 6.1 Region dependent: soil, stored cerealproducts, soil, foodstuffs, dairy products,textiles, compost, and house dust

Fusarium 5.6 Worldwide: soil and plantsAureobasidium 4.7 Worldwide: soil, decaying pears and

oranges, paint, wood, and paper

Source: From Al Doory, Y., and J.F. Domson. Mould Allergy. Lea & Febiger,Philadelphia, Pennsylvania (1984). With permission.


travel, in extreme cases, as far as 1500 miles, and it is common to find them100 miles from their point of origin. More simply stated, their source doesnot necessarily have to be in the immediate vicinity.

Mushrooms

Mushrooms are filamentous fungi that typically form large structures,called fruiting bodies. The fruiting bodies unite to form a large mass com-monly referred to as the mushroom. A typical mushroom is comprised of afungal cap which produces millions of spores in the gills on the undersideof the mushroom; it may or may not have a stem. After a rain, mushroomspop up everywhere (e.g., fields, gardens, yards, etc.) and millions of sporesare discharged into the air. These myriad spores are visible as dark clouds ofdust billowing from the underside of the mushroom(s), and they contributeto most of the outdoor airborne fungal spore population—particularly aftera rain shower. See Figure 4.5 for life cycle of mushrooms.

TABLE 4.5

Number of Spore Discharges from One Source

Ganoderma applanatum 30 billion/dayDaldinia concentrica 100 million/dayPenicillium spp. 400 million/day

Source: From Smith, E.G. Sampling and Identifying Allergenic Pollens and Molds: An Illustrated Identification Manual for Air Samplers.Blewstone Press, San Antonio, Texas (1990). With permission.

FIGURE 4.5Life cycle of mushrooms.


Although it is unlikely that mushrooms will grow indoors without intent(e.g., cultivation of edible mushrooms), mushroom-like fungi can and dogrow on wet structural lumber. Some grow away from a water source (e.g.,saturated lumber in a crawl space), branch out, and grow into and damagedry lumber. This fruiting body is referred to as “brown rot” (e.g., dry rot).Other mushroom-like fungi (e.g., white rot) grow only at the water sourceand only damage wet wood. See Figure 4.6.

Rusts and Smuts

Single-celled rust and smut proliferate to form thick-walled, binucleatespores. With an excess of 20,000 species, “rust” fungi are so referenced due

FIGURE 4.6Source of indoor mushroom spores—dry rot (Serula lacrymans) fruiting body covered with mil-lions of rust/red colored fungal spores (top left) and fungal-damaged lumber with cuboid-likecracking of apparently dry wood (top right); white rot (Asterostroma spp.) growth on structuralwood supporting flat roof (bottom left); and white rot (Phellinus contiguous) growth on wet woodaround windows (bottom right). (Courtesy of Remedial Technical Services, United Kingdom)

(a) (b)

(c) (d)


to an orange–red color imparted to diseased plants when the plants becomeinfected. Heavily infected plants look like they are covered with iron oxiderust. Rusts do not grow indoors unless their host plants are present andinfected.

“Smut” fungi have more than 1000 species. The term smut is assignedto this class of fungi because the thick-walled spores impart a black, sootyappearance to plants. The levels of smut indoors are generally equal to or lessthan that of the outdoor air, but if the smut and rust spore levels equal theoutdoor air, the fresh air is not adequately filtering the air.

Slime Molds

Slime molds are not true fungi but are related instead to the protists, and theylack, for most of their lives, a cell wall. Laboratory reports refer to slime moldsby their taxonomic category—myxomycetes. The term slime mold refers tothe swarming bodies of amoeboid cells during part of their life cycle. In thisstage many of the slime molds display brilliant colors and appear mucoid ona nutrient surface.

The slime molds have an interesting life cycle that includes a wet, amoe-boidlike phase and a dry spore phase. See Figure 4.7. When conditions arefavorable, they live primarily on decaying plant matter (e.g., leaf litter andlogs) and bacteria-rich soils. Their food consists mainly of other microorgan-isms (e.g., bacteria and yeasts), and they ingest by phagocytosis. During thewet phase they do not pose a problem.

During the dry phase, however, they form stalks that produce spores (ormultiple spore-containing sporangia) that are subsequently released into theair. Slime mold spores can contribute to the total fungal spore count. It shouldbe noted, however, that their spores may easily be mistaken for smuts.

FIGURE 4.7Life cycle of slime molds.


Bacteria6

Bacteria are single-celled organisms usually less than 1 micron in diameter,but they can be as large as 5 microns. The actinomycetes are filamentousbacteria that can produce structures that have an appearance similar to smallmold spores and can contribute to the total allergenic spore count. Theirspores are also allergenic.

Actinomycetes are spherical or oval in shape and range in diameter from0.8 to 3 microns, similar to that of Aspergillus/Penicillium. However, theirnutrient requirements are complex. They grow best in rich organic materialand tolerate extremes in temperature. Thus they do not grow in conditionssimilar to those found in most office buildings, although extensive growthof actinomycetes may be seen on building materials in damp crawlspaces.Differentiating the mold and bacteria spores can be accomplished by micros-copy or culturing viable spores.

Bacilli are rod-shaped, spore-forming bacteria. They are generally associ-ated with food spoilage and are not likely to be airborne.

Indoor Source Information

Although indoor pollen grain exposures are generally less than outdoorexposures, reduced pollen count indoors may still contribute to the totalallergen loading to which an individual is exposed. There are also excep-tions to the rule in that indoor pollen counts, on rare occasion, may be greaterthan outdoor counts. In the latter case, pollen may have entered a buildingduring the pollen season when the windows and doors were open and onceinside the building, the pollen enters into a recycling mode within a poorlyfiltered air handling system. The investigator should not be blinded to allpossibilities.

Fungal spores also enter the indoor air from outside, and the total sporecount is generally less indoors than it is outside. With mold spores, the totalindoor mold spore count is typically 10 percent to 50 percent less than theoutside air. Yet unlike the pollen grains, molds and occasionally other fungican grow indoors. Not only does their growth contribute to the total count,but some types of molds pose a greater health concern than others. For thisreason, an effort to identify fungal types is necessary to characterize theirimpact.

Once again, there are exceptions to the rule in that indoor mold sporesmay on occasion be greater indoors than outside. When this occurs at lowlevels (e.g., less than 200 counts/m3 outside), it may be the result of outsideconditions that have minimized the outside mold spore count (e.g., immedi-ately after a rain, which tends to settle particles and mold spores out of theair), or it may be the result of normally low outside levels with amplification,or growth, of molds indoors. Normal conditions will come with experiencein air sampling within a given region. For instance, outside airborne mold


levels in St. Louis, Missouri, is typically in excess of 2000 counts/m3 (as highas 62,000 counts/m3), whereas outside air in Las Vegas, Nevada, is normallyless than 100 counts/m3 (rarely higher than 2000 counts/m3). A clear case ofamplification indoors would be an outside level of 11,000 count/m3 and anindoor exposure of 44,000 counts/m3.

Fungal species have different growth requirements, habitats frequented,health effects, and levels of concern. Yet to capture and count all allergenicfungal spores, the investigator must settle for a more generalized character-ization of fungal spores and proceed to Chapter 5 for identification of genusand, in some cases, species. See Table 4.4 for information regarding fungalidentification generally within the scope of the sampling methodology pre-sented within this chapter.

Sampling Strategy

The investigator should determine the purpose for air sampling, and the pur-pose should assist the investigator to identify the area(s) to be sampled. Theymay be based on identification of one, or a combination of the following: (1)perceived worst case scenario(s); (2) representative of area(s) frequented; and(3) areas of special concern (e.g., infant nursery). These sample areas shouldbe compared to at least one outside air sample and, if possible, one noncom-plaint area such as may occur in an office building. Once the site or sites havebeen selected, sample duration should be considered.

The occupants’ health and exposure duration are factors to consider whendeciding the type of air sampling to be performed. The exposure consider-ations for a healthy adult at work in an office building will be different fromthat of an elderly patient confined to a hospital bed.

Activities should also be taken into consideration. Some activities mayimpact the exposure levels more than others. For instance, maintenanceremoving ceiling tiles in an office building may result in a twofold tothreefold increase in the spore counts. Custodial vacuuming and dustingmay result in increased counts. Aggressive agitation of bedding, textiles,and clothing may result in increased counts. A humidifier may result indecreased counts. Sometimes these peak exposure activities go unnoticedwithout more extensive samples per site throughout the day or a time-dis-crete sampler.

Based on each scenario, the investigator must decide on the appropri-ate sampling method. These methods are typically short-term, snapshotsamples of several sites or short-term, time-discrete samples over a periodof time.


Sampling and Analytical Methodologies

In indoor air quality sampling, the sampling methodologies of choice arethe slit-to-cover-slip sample cassettes (e.g., Allergenco-D, Air-O-Cell) andslit-to-slide samplers (e.g., Allergenco™ Spore Trap, Burkard Spore Sampler).They all perform on a similar principle but vary in up-front cost, ongoingexpenses, and ease of handling large sample numbers.

Try not to compare sample results taken by two different approaches.Taking two samples using the same sampler at the same time and in thesame approximate location may result in differences because no two air sam-ples are identical. Comparing samplers is a job for researchers. Choose onesampler and stay with it.

Slit-to-Cover-Slip Sample Cassettes

The slit-to-cover-slip sampling methodology is often referred to as spore trapcassette sampling. The cassette has a slit opening through which air passesand particles adhere to the surface of a sticky substance (e.g., triacetin) on thesurface of a cover slip. The air is drawn through the cassette by means of anair sampling pump. See Figure 4.8.

During sampling, the protective tape on either side of the cassette isremoved. The cassette is connected to a calibrated air sampling pump, air issampled for an abbreviated time period, and the cassette is resealed and sentto a laboratory for analysis. A generalized summary of the method follows:

• Equipment: air sampling pump and timer• Collection medium: spore trap cassette• Flow rate: 15 liters/minute• Recommended sample duration: 1 to 10 minutes, based on antici-

pated loading

Anticipated loading is based on conditions and activities. Where excessiveloading occurs on the slide, enumeration becomes difficult if not impossible.In the latter case, samples may be significantly underestimated and difficultto identify.

In clean office environments and outside where there is very little dustanticipated, sampling should be performed for 10 minutes. In dusty areasor areas where there is considerable renovation, a 1-minute sample shouldbe considered. Indoor air environments where there is moderate dust orwhere considerable levels of mold spores (e.g., greater than 500 spores) areanticipated, the sampling duration should be reduced accordingly (e.g., 5 to8 minutes). Experience will be the investigator’s best guide.


Slit-to-Slide Samplers

The slit-to-slide sampler operates by impacting particles onto a treatedmicroscope slide. An internal pump draws air through the slit at a flowrate of 15 liters per minute. Sampling duration may be from 1 to 10 min-utes, and the samplers can be programmed to collect a different sample atdesignated sample intervals. For instance, the Allergenco™ Spore Trap canbe programmed to collect 24 discrete samples, once an hour for a total of 24samples per slide.

With the ability to program the sampler, the investigator may find the slit-to-slide sampler easier to manage than the cassettes. One location can beassessed over an extended period and trends documented for time versesconcentration.

A generalized summary of the method follows:

• Equipment: Burkard™ 7-Hour Spore Trap or AllergencoTM Spore Trap• Collection medium: treated microscope slide

FIGURE 4.8Spore Trap Sampler—Battery-operated Buck BioAir with Air-O-Cell cassette.


• Flow rate: 10 to 15 liters/minute• Recommended sample duration: 5 to 10 minutes, based on antici-

pated loading

Analytical Methods

Samples are received, stained, covered (e.g., cover slip on the microscopeslide), and examined under an optical microscope. Counts are generally per-formed with a 40x objective, and identification may be performed using the100x oil immersion.

The entire impacted surface area should be counted and results given interms of fungal spore characterization (e.g., myxomycetes) as well as sporeand pollen counts per cubic meter of air. Characterization identifies fungalspores by categories (e.g., rusts) and mold spores by groups (e.g., Aspergillus/Penicillium), and some of the more morphologically unique molds by genus(e.g., Stachybotrys).

Commercial Laboratories

In recent years, commercial laboratories have been popping up like mush-rooms after a heavy rain. They came, they saw, and they conquered. Althoughthere are attempts under way by universities (e.g., Harvard School of PublicHealth) and nationally recognized organizations (e.g., American IndustrialHygiene Association) to certify analysts and laboratories, many analysts areinexperienced, and there is no quality control watchdog.

On the other hand, there are some very competent, experienced laborato-ries that charge a little extra, are not local, or have longer turnaround times.The trade-off may be worth it. It can be disconcerting to compare two sepa-rate laboratory results of the same samples only to find one laboratory statethe counts are excessive while the other fails to detect any levels. If there isa divergence from any of the basic laboratory approaches mentioned aboveor the results appear inconsistent, seek a second opinion.

Helpful Hints

A dilemma that many investigators ponder is what equipment to purchase.Should the investigator choose to perform time-discrete sampling, thenumber of sample sites is limited by the number of impactors available.Multiple sampling of several sites may be performed by any of the previ-ously mentioned methods, and time-discrete sampling may be performedby the environmental unit Burkard Spore Trap and the Allergenco™ AirSampler.


The handling of the treated slides that are used in the impactor must bedone with caution. Once treated, the slides must be kept clean and shouldnot be touching other surfaces, including other microscope slides. The slidemay be maintained and transported in a box or plastic container specificallymade for this purpose.

This is generally not a problem with the single-use, disposable, spore trapcassettes. The cassette air inlets are sealed prior to sampling and shouldbe resealed upon sample completion, but no manipulation of the adhesive-coated sample inside the cassette is required.

Although the initial cost of the air sampling pump for use with spore trapcassettes is less than the slit-to-slide impactors, the cost of the cassettes canquickly outweigh the initial cost of the impactors.

Due to its limitations, the Rotorod™ has not been discussed herein. Usedin the past for community allergy alert reporting (primarily pollen), theRotorod™ has a rotating rod with a built-in 24-hour interval timer. It is easyto use, and the results are read in terms of counts/m3. Its limitation, how-ever, is in the size of particles impacted onto the rod. There is a considerabledrop-off of smaller particles, particularly the spores that are most commonlyfound to be problematic in indoor air quality (e.g., Aspergillus and Penicilliummolds).

When not able to program the sample time, use a good timer, preferablyone that counts down in seconds. Some timers count down in minutes, and itis difficult to anticipate stop sampling time. The author prefers a timer with abuilt-in turn off switch (e.g., darkroom clock). It is easy to become distractedwhile waiting for the sample to be collected.

Keep notes of conditions at each sample location. These should includeexact location within the room, air movement (e.g., air supply not on whilesampling), distance from air supply vents, occupancy (e.g., nighttime nooccupancy), and activities (e.g., busy area). Many investigators also log tem-perature, relative humidity, and carbon dioxide levels.

Interpretation of Results

Although there are no indoor air quality standards for interpreting pollenand mold spore counts, the National Allergy Bureau has set some guide-lines based on ecological measurements for outdoor air. As health effects aredependent on individual susceptibility, the relative exposure index is notbased on health effects. They are relative numbers and limits. Yet an inves-tigator may excerpt in part or parcel usable information from these tables.See Table 4.6.


The National Allergy Bureau is a section of the American Academy ofAllergy, Asthma and Immunology (AAAAI) Aeroallergen Network that isresponsible for reporting current pollen and mold spore levels to the media.The network is a group of pollen and spore counting stations staffed byAAAAI members who volunteer to donate their time and expertise in pro-viding the most accurate and reliable pollen and mold counts from morethan 65 counting stations throughout the United States and Canada. Theyuse the seven-day long-term Burkard™ Spore Trap in the performance oftheir sampling.

Beginning in 1992, the National Allergy Bureau compiled records reportedby each of the stations. These are broadcast to the media, and they are postedon the Bureau’s Web site (http://www.aaaai.org/nab). These records andadditional allergy information can be accessed by the public.

As for assessing indoor air quality, sample results may require additionalconsiderations. The indoor counts should be compared to outdoor countsand, if possible, to indoor noncomplaint areas, and the types of fungal sporesfound indoors versus those found outdoors may be compared when assess-ing the potential source of mold spores as being indoors. Comparing lowlevels of fungal spores, however, can be misleading.

According to former Harvard professor Harriet Burge11, the statistical“probability of a calculated number representing the actual concentrationbecomes significant at an actual count of about 10 spores.” For a 5-minutesample at 15 liters per minute, the calculated concentration is 133 counts/m3.She proceeds to point out that she considers concentrations less than 200counts/m3 of little quantitative importance, regardless of taxon (i.e., moldgenus).

It is suggested that when making comparisons, do not place a wholelot of credence on type and total concentrations of less than 200counts/m3.

Spore identification without observed growth patterns, but characteriza-tion and partial identification is useful in determining indoor amplificationof molds. See Tables 4.7 and 4.8 for generalized characterization of moldtypes and for information regarding occurrence.

TABLE 4.6

National Allergy Bureau Guideline for Relative Exposures to Outdoor AirPollen and Spores (counts/m3)8

Allergen Very Low Low Medium High Very High

Molds <500 500–1,000 1,000–5,000 5,000–10,000 >20,000Pollen 1–50 50–100 100–500 500–1,000 >1,000

62 IndoorAirQuality:TheLatestSamplingandAnalyticalMethodsTA

BLE

4.7

Cha

ract

eris

tics

ofM

old

s

Gen

us

Wh

ere

Fou

nd

in N

atu

reS

ub

stra

tes/

Con

dit

ion

s fo

r G

row

th I

nd

oors

Acr

emon

ium

soil,

dea

dor

gani

cd

ebri

s,ha

y,fo

odst

uffs

rott

ing

food

;ver

yw

etco

ndit

ions

Alt

erna

ria

soil,

dea

dor

gani

cd

ebri

s,fo

odst

uffs

,tex

tile

s(s

ome

plan

tpa

thog

ens)

cellu

lose

and

leat

her;

84–8

8%re

lati

vem

oist

ure;

som

eca

ngr

owat

free

zing

tem

pera

ture

s

Art

hrin

ium

soil,

dec

ompo

sing

plan

tmat

eria

lra

rely

enco

unte

red

ind

oors

Asp

ergi

llus

soil,

dec

ayin

gpl

antd

ebri

s,co

mpo

stpi

les,

stor

edgr

ain

cellu

lose

;65–

98%

rela

tive

moi

stur

e

Aur

eoba

sidi

umso

il,fo

rest

soils

,fre

shw

ater

,aer

ialp

orti

onof

plan

ts,f

ruit

wid

espr

ead

whe

rem

oist

ure,

espe

cial

lyin

bath

room

san

dki

tche

ns,o

nsh

ower

curt

ains

,tile

grou

t,w

ind

owsi

lls,

text

iles,

liqui

dw

aste

Bea

uver

ia

soil,

plan

tdeb

ris,

dun

g,in

sect

para

site

sra

rely

enco

unte

red

ind

oors

Bot

ryti

sso

il,st

ored

and

tran

spor

ted

frui

tand

vege

tabl

es,p

lant

path

ogen

,sap

roph

yte

onfl

ower

s,le

aves

,ste

ms,

and

frui

t,le

afro

ton

grap

es,s

traw

berr

ies,

lett

uce,

cabb

age,

onio

ns

grow

son

ind

oor

plan

ts;>

93%

rela

tive

moi

stur

e

Can

dida

(yea

st)

end

osym

bion

tsC

and

ida

albi

cans

isge

nera

llyex

pelle

dby

hum

ans

who

have

been

onlo

ngte

rman

tibi

otic

sor

ster

oid

s

Cer

atoc

ysti

s, O

pios

tom

aco

mm

erci

allu

mbe

r,tr

ee,a

ndpl

antp

atho

gen

“lum

ber

mol

d”;

asso

ciat

edw

ith

fres

hly

cutl

umbe

r;in

doo

rex

posu

res

may

notb

eas

soci

ated

wit

hw

ater

dam

age;

>16

%m

oist

ure

cont

ent

Cer

cosp

ora

para

site

ofhi

gher

plan

ts,c

ausi

ngle

afsp

otra

rely

enco

unte

red

ind

oors

Cha

etom

ium

soil,

seed

s,ce

llulo

sesu

bstr

ates

,dun

g,w

ood

yan

dst

raw

mat

eria

lsce

llulo

se

Cla

dosp

oriu

mso

ilof

man

yd

iffe

rent

type

s,pl

antl

itte

r,pl

antp

atho

gen,

leaf

surf

aces

,old

ord

ecay

edpl

ants

text

iles,

cellu

lose

,moi

stw

ind

owsi

lls,w

etd

ucti

nsul

atio

n,ti

legr

out,

plac

esw

here

rela

tive

hum

idit

yis

grea

ter

than

50%

;82-

88%

rela

tive

moi

stur

e;so

me

can

grow

infr

eezi

ngte

mpe

ratu

res

PollenandSporeAllergens 63C

urvu

lari

apl

antd

ebri

s,so

il,fa

cult

ativ

epl

antp

atho

gens

oftr

opic

alan

dsu

btro

pica

lpla

nts

vari

ety

ofsu

bstr

ates

Dre

chsl

era,

Bip

olar

is, a

nd

Exs

eroh

ilum

plan

tdeb

ris,

soil,

plan

tpat

hoge

ns(p

arti

cula

rly

gras

ses)

vari

ety

ofsu

bstr

ates

Epi

cocc

umpl

antd

ebri

s,so

il,se

cond

ary

inva

der

ofd

amag

edpl

ants

pape

r,te

xtile

s,an

din

sect

s;>

86%

rela

tive

moi

stur

e

Fusa

rium

soil,

sapr

ophy

tic

orpa

rasi

tic

onpl

ants

,pla

ntpa

thog

ens

cellu

lose

,coo

ling

coils

inai

rha

ndle

rs,c

arpe

ting

,tex

tile

s,se

eds

and

frui

ts;8

6-91

%re

lati

vem

oist

ure

Muc

oror

gani

cm

atte

r,d

ung,

soil

vari

ety

ofsu

bstr

ates

,rot

ting

food

,sof

tfru

its

and

frui

tju

ices

;90–

94%

rela

tive

moi

stur

e

Myr

othe

cium

gras

ses,

plan

ts,a

ndso

il;d

ecay

ing

frui

ting

bod

ies

ofR

ussu

lam

ushr

oom

sra

rely

enco

unte

red

ind

oors

Nig

rosp

ora

dec

ayin

gpl

antm

ater

iala

ndso

ilra

rely

enco

unte

red

ind

oors

Pae

cilo

myc

esso

ilan

dd

ecay

ing

plan

tmat

eria

l,co

mpo

stin

gpr

oces

ses,

legu

mes

,cot

tons

eed

s,so

me

spec

ies

para

siti

zein

sect

sju

tefib

ers,

pape

r,PV

C,t

imbe

r(o

akw

ood

),op

tica

llen

ses,

leat

her,

phot

ogra

phic

pape

r,ci

gar

toba

cco,

harv

este

dgr

apes

,bot

tled

frui

t,an

dfr

uitj

uice

und

ergo

ing

past

euri

zati

on;>

80%

rela

tive

moi

stur

e;so

me

can

grow

atte

mpe

ratu

res

ashi

ghas

122°

F

Pen

icill

ium

soil,

dec

ayin

gpl

antd

ebri

s,co

mpo

stpi

les,

and

rott

enfr

uit

cellu

lose

,dri

edfo

ods,

chee

ses,

frui

ts,h

erbs

,spi

ces,

cere

als,

carp

et,a

ndgl

ues;

80–9

0%re

lati

vem

oist

ure

Per

icon

iaso

il,bl

acke

ned

and

dea

dhe

rbac

eous

stem

san

dle

afsp

ots,

gras

ses,

rush

es,s

edge

sra

rely

enco

unte

red

ind

oors

Pho

ma

plan

tmat

eria

l,so

il,fr

uitp

aras

ite

cellu

lose

,rev

erse

sid

eof

linol

eum

(e.g

.,gl

ue);

cem

ent,

pain

t,pa

per,

woo

l,an

dro

ttin

gfo

od(e

.g.,

rice

and

butt

er);

spor

esno

trea

dily

dis

sem

inat

edby

air

curr

ents

Pit

hom

yces

dea

dle

aves

,soi

l,gr

asse

sce

llulo

se

Rhi

nocl

adie

llaso

il,he

rbac

eous

subs

trat

es,a

ndd

ecay

ing

woo

dva

riet

yof

subs

trat

es,f

ound

arou

ndw

ine

cella

rson

bric

kwor

kan

dad

jace

ntti

mbe

r

(con

tinu

ed)


BLE

4.7

(C

ON

TIN

UED

)

Cha

ract

eris

tics

ofM

old

s

Gen

us

Wh

ere

Fou

nd

in N

atu

reS

ub

stra

tes/

Con

dit

ion

s fo

r G

row

th I

nd

oors

Rhi

zopu

sfo

rest

and

cult

ivat

edso

ils,d

ecay

ing

frui

tsan

dve

geta

bles

,an

imal

dun

g,an

dco

mpo

st;a

para

siti

cpl

antp

atho

gen

onco

tton

pota

toes

,and

vari

ous

frui

ts

vari

ety

ofsu

bstr

ates

,foo

d;9

0-93

%re

lati

vem

oist

ure

Spor

obol

omyc

es (y

east

)tr

eele

aves

,soi

l,ro

ttin

gfr

uit,

othe

rpl

antm

ater

ials

,as

soci

ated

wit

hle

sion

sca

used

byot

her

plan

tpar

asit

esva

riet

yof

subs

trat

esve

ryw

etco

ndit

ions

Stac

hybo

trys

soil,

dec

ayin

gpl

ants

ubst

rate

s,d

ecom

posi

ngce

llulo

se(h

ay,

stra

w),

leaf

litte

r,an

dse

eds

cellu

lose

,jut

e,w

icke

r,st

raw

bask

ets;

91–9

4%re

lati

vem

oist

ure

Stem

phyl

ium

soil,

woo

d,d

ecay

ing

vege

tati

on,s

ome

spec

ies

plan

tpa

thog

ens

rare

lyen

coun

tere

din

doo

rs

Toru

laso

il,d

ead

herb

aceo

usst

ems,

woo

d,g

rass

es,s

ugar

beet

root

,gr

ound

nuts

,and

oats

surf

ace

ofun

glaz

edce

ram

ics,

and

cellu

lose

cellu

lose

Tric

hode

rma

soil,

dec

ayin

gw

ood

,gra

ins,

citr

usfr

uit,

tom

atoe

s,sw

eet

pota

toes

,pap

er,t

exti

les,

dam

pw

ood

pape

r,ta

pest

ry,w

ood

,rot

ting

food

Ulo

clad

ium

soil,

dun

g,pa

int,

gras

ses,

fiber

s,w

ood

,dec

ayin

gpl

ants

,pa

per,

and

text

iles

gyps

umbo

ard

,pap

er,p

aint

,tap

estr

ies,

jute

,and

othe

rst

raw

mat

eria

ls;h

igh

wat

erre

quir

emen

t,re

lati

vely

dry

surf

aces

Wal

lem

iaso

il,fo

odst

uffs

,hay

,tex

tile

s,sa

lted

fish

woo

d/

lum

ber

incr

awls

pace

s,te

xtile

san

dm

attr

esse

s(e

.g.,

likel

yto

thri

veon

skin

cells

ind

ust)

;65

–87%

rela

tive

moi

stur

e

Exc

erpt

edfr

om“C

hara

cter

isti

csof

Som

eC

omm

only

Enc

ount

ered

Fung

alG

ener

a.”10

Supp

limen

ted

from

“Eco

met

rex

Fact

Shee

t-M

oist

ure

Req

uire

men

tsfo

rM

old

Gro

wth

.”w

ww

.eco

met

rex.

com

/m

oist

ure.

htm

;“C

andi

da(g

enus

).”w

ww

.en.

wik

iped

ia.o

rg/

wik

i/C

and

ida_

(gen

us);

and

“Pas

teur

Lab

orat

ory-

Som

eC

omm

onFu

ngi

and

The

irH

ealt

hE

ffec

ts.”

ww

w.

past

eurl

abor

ator

y.co

m/

com

mon

1.ht

mce

llulo

se—

dry

wal

lpap

er,c

ellu

lose

ceili

ngti

les

(not

fiber

glas

s),j

ute

(e.g

.,na

tura

lcap

etba

ckin

g),a

ndun

trea

ted

lum

ber


TAB

LE 4

.8

Broa

dC

ateg

orie

sof

Fung

alSp

ores

Iden

tifie

dby

Spor

eTr

ap10

Cat

egor

ies

of S

por

esa

Wh

ere

Fou

nd

in N

atu

reS

ub

stra

tes/

Con

dit

ion

s for

In

doo

r Fu

nga

l Gro

wth

Asc

osp

ores

: lar

gefr

uiti

ngbo

die

sw

hose

spor

esar

epr

oduc

edin

sid

ea

sack

(e.g

.,m

orel

s,tr

uffl

es,c

upfu

ngi,

ergo

t,an

dm

any

mic

ro-f

ungi

)

sapr

ophy

tes

and

plan

tpat

hoge

nsd

amp

soil

(e.g

.,in

doo

rpl

ants

)ve

ryw

etor

gani

cm

ater

ial(

e.g.

,woo

dan

dna

tura

lfibe

rca

rpet

ing)

Bas

idio

spor

es: l

arge

frui

ting

bod

ies

who

sesp

ores

are

prod

uced

exte

rnal

ly(e

.g.,

mus

hroo

ms,

puff

balls

,she

lffu

ngi,

brac

ket

fung

i,ea

rth

star

s,st

inkh

orns

,jel

lyfu

ngi,

and

othe

rco

mpl

exfu

ngi)

sapr

ophy

tes

and

plan

tpat

hoge

nsga

rden

s,fo

rest

s,w

ood

land

s“d

ryro

t”—

fung

usor

igin

ates

inw

etlu

mbe

r(e

.g.,

wet

soil

incr

awls

pace

s,le

akin

gro

ofs

and

win

dow

s),m

igra

tes

to/

thro

ugh

and

dam

ages

dry

lum

ber

(dry

,cra

cked

woo

d)

“whi

tero

t”—

wet

lum

ber,

doe

sno

tmig

rate

beyo

ndm

oist

ure

sour

ceC

oelo

myc

etes

: ass

exua

lfila

men

tous

fung

ith

atfo

rmco

nid

iain

aca

vity

orm

at-l

ike

cush

ion

ofhy

phae

sapr

ophy

tic

orpa

rasi

tic

onhi

gher

plan

tsan

dot

her

fung

igr

ows

onlic

hens

and

vert

ebra

tes

surf

aces

inhi

ghhu

mid

ity

area

s(e

.g.,

tile

sin

bath

room

san

dsh

eetv

inyl

inar

ound

dis

hwas

hers

);sp

ores

not

read

ilyd

isse

min

ated

,mor

elik

ely

enco

unte

red

onsu

rfac

esa

mpl

esM

yxom

ycet

es: s

lime

mol

ds

dec

ayin

glo

gs,s

tum

psan

dd

ead

leav

es,

part

icul

arly

info

rest

edre

gion

sra

rely

foun

dgr

owin

gin

doo

rs(e

.g.,

wet

dec

ayin

gw

ood

)

Ru

sts

gras

ses,

flow

ers,

fern

s,an

dtr

ees

rare

lyfo

und

grow

ing

ind

oors

(e.g

.,in

doo

rpl

ants

)S

mu

ts

cere

alcr

ops

(e.g

.,co

rnan

dw

heat

),gr

asse

s,w

eed

s,an

dfl

ower

ing

plan

tsra

rely

foun

dgr

owin

gin

doo

rs(e

.g.,

ind

oor

plan

ts)

aC

ateg

orie

sof

fung

alsp

ores

are

spor

esth

atca

nnot

bed

iffe

rent

iate

dby

spor

etr

apan

alys

ison

ly.T

hete

rm“c

ateg

ory”

isa

labo

rato

ryd

esig

nati

on,n

ota

mea

nsof

clas

sific

atio

n.N

OT

E:

As

the

ind

oor

fung

alle

vels

typi

cally

lag

that

ofou

tdoo

rs,a

mpl

ifica

tion

isin

dic

ated

only

inex

trem

eca

ses

such

asw

here

ind

oor

leve

lsex

ceed

outd

oor

leve

lste

nfo

ld.L

ess

than

atw

ofo

ldel

evat

ion

ind

oors

over

that

ofou

tdoo

rsm

ayre

flec

twha

tthe

outd

oor

leve

lsw

ere

two

day

spr

ior

and

have

yetb

efl

ushe

dfr

omth

eai

rha

ndlin

gsy

stem

.


Summary

There are no standards for interpreting pollen/spore counts and their effecton human health. The investigator can assess total relative pollen and sporecounts and, to a limited extent, compare types to determine amplificationindoors. For a more thorough identification and comparison of types in deter-mining indoor amplification of molds, the investigators should also performviable mold air sampling in tandem with the viable/nonviable methods inthis chapter. See Chapter 5.

References

1. Aeroallergen Network of the American Academy of Allergy, Asthma andImmunology (AAAAI). U.S. Pollen Calender. AAAAI, Milwaukee, Wisconsin(July 1993).

2. Smith, E.G. Sampling and Identifying Allergenic Pollens and Molds: An Illustrated Identification Manual for Air Samplers. Blewstone Press, San Antonio,Texas (1990), p. 43.

3. ACGIH. Bioaerosols: Airborne Viable Microorganisms in Office EnvironmentsSampling Protocol and Analytical Procedures. Applied Industrial Hygiene (April1986), p. R 22.

4. Cole, G.T., and H.C. Hock. The Fungal Spore and Disease Initiation in Plants and Animals. Plenum Press, New York, New York (1991), p. 383.

5. Al Doory, Y., and J.F. Domson. Mould Allergy. Lea & Febiger, Philadelphia,Pennsylvania (1984), pp. 36–7.

6. Smith, E.G. Sampling and Identifying Allergenic Pollens and Molds: An Illustrated Identification Manual for Air Samplers. Blewstone Press, San Antonio, Texas (1990),p. 16.

7. Ibid. p. 42.8. Pinnas, J.L. Parameters for Pollen/Spore Charts (Letter). National Allergy Bureau,

Tucson, Arizona (November 28, 1994).9. Bleimehl, L. Issues Concerning the National Allergy Bureau (Oral communication).

AAAAI, Milwaukee, Wisconsin (January 1996).10. Abbott, Sean (discussion) Natural Sink Mold Lab October 20, 2010. Categories of

spores and where/when they are found window.11. Burge, H. What Is the Proper Way to Interpret Mold Reports? Indoor Environ

mental Connections (newspaper), 11:3 (January 2010), p. 15.

67

5ViableMicrobialAllergens

Microbial allergens are microscopic organisms that may cause allergy symp-toms. Mold spores are the most commonly recognized microbial allergens,reported to affect more than 20 percent of the adult population. Other lesscommonly recognized microbial allergens are spore-forming bacteria.

Microbial organisms may be culturable (i.e., grown under laboratory con-ditions), nonculturable, or dead, and they may elicit the same effect, irrespec-tive of viability. On the other hand, not all microbes are allergens. Some arehuman pathogens (e.g., tuberculosis). Many affect our lifestyles (e.g., mold inthe home) and crops (e.g., crop pathogens). Others have no apparent, directimpact on our lives. Yet they may all be airborne.

Airborne microbial allergens are indoors and outdoors. Generally, the out-door levels are greater than the indoor levels. Even when the outdoor levelsexceed the indoor levels, identification of the indoor and outdoor microbialallergens by genus and species is a means for determining amplificationindoors. This is done by culturing viable microbes. A viable organism is onethat is capable of growing and completing a life cycle. Thus microbes canonly be reliably differentiated when their viability is retained. If they aredead, cannot grow on culture media, or cannot form spores when grown onculture media, microbial allergens cannot be identified.

Although the health effects of viable allergens and nonviable allergens arethe same, sample collection and interpretation methods are distinctly differ-ent. Airborne viable microbial air sampling is more involved than nonviablesampling. Viable air sampling is the only way to definitively identify moldspores by genus and species, but other fungal spores (e.g., smuts and rust) arerarely cultured. In the latter, the most efficient way to sample is for viable/nonviable spores.

The information obtained through viable sampling contributes signifi-cantly toward the overall picture and interpretation of exposures to moldspores. Mold spores are a major contributor to indoor air quality allergens.

Occurrence of Allergenic Microbes

Viable allergens are herein discussed to lend an understanding to the readeras to the potential sources and growth requirements needed for enhance-ment and amplification of allergenic microbes. The principal allergen in


each case is thought to be airborne spores with minimal concern for theassociated growth structures. The two major categories are fungi and ther-mophilic actinomycetes.

Those microbes which have been excluded from this allergenic microbeslist are either pathogenic or have not been reported as probable allergens.The pathogenic microbes are discussed separately in Chapter 6.

Fungi

Molds and other fungal allergens were discussed in the preceding chapterunder the section “Spore-Producing Fungi and Bacteria.” Yet the intent wasto discuss basic characteristics, not differences between the specific fungi.As they can be more readily identified, we discuss herein details regardingspecific fungi, their habitats, and unique characteristics.

Molds

Contrasted with the hardiest of microbes, molds not only can stay aliveindefinitely on inanimate objects, or fomites, but they can grow into anddestroy wood, cloth, fabrics, leather, twine, electrical insulation, and manyother commercial products. They destroy lenses of microscopes, binoculars,and cameras. In localities where humidity is high, fungi do great harm towood structures, telephone poles, railroad ties, and fence posts. Most ofthese problems are reduced by means of artificial preservatives. Sometimesthe trouble starts in forests where fungi invade the heartwood and causewood rot before the timber has had a chance to be cut down. The humidAmazon rain forest is one such example.

Thousands of products are treated to prevent decay, yet there are sometypes of fungi that thrive on preservative-treated wood. One such exam-ple is creosote-treated railroad ties! Other fungi-specific nutrients are vinylwall covering adhesives, gypsum board, cellulose-based ceiling tiles, dirtretained within carpeting, and surface paints. Some feed on plywood. Othersconsume the glue used to laminate wood that is used in airplanes, furni-ture, and cars and will cause the layers to separate. Books and leather shoesare readily consumed by the microbes that are visible as mildew. Aircraftelectrical systems, operating in tropical climates, require protection againstinsulation-consuming molds. Immune-suppressed individuals (e.g., AIDSpatients) can also be host to normally nonpathogenic molds.

Exterior molds grow on decayed organic material, corn, wheat, barley, soy-beans, cottonseed, flax, and sun-dried fruits. They consume other plants,vegetable matter, and decayed organic material (e.g., dead animals).

Pathogenic molds parasitize and obtain nutrients from a host. The host maybe plant or animal, and these molds vary slightly from the nonpathogenicmolds both in environmental and sampling requirements. Thus they are dis-cussed in greater detail in Chapter 6.

ViableMicrobialAllergens 69

Most molds require high moisture in order to grow. Most require mois-ture content in excess of 80 percent, some do quite well at levels as low as60 percent. The latter are referred to as xerophylic (dry-loving) fungi. WhereasStachybotrys requires considerable moisture (91–94% relative moisture at alower level (80–85% relative moisture). Mold that requires low moisture lev-els is inhibited by high moisture content. Aspergillus versicolor does well. SeeTable 5.1 for water requirements of some of the more common microorgan-isms, and see Table 5.2 for moisture requirements of the more common fungi,identified by moisture preferences.

Temperature preferences are variable as well. Although most moldsdo well at room temperature, some flourish at near-freezing temperature

TABLE 5.1

Moisture Requirements of Common Microorganisms

MicroorganismWater Activity

(% Relative Moisture)

Aspergillus halophilicus and Aspergillus restictusAspergillus glaucus and Wallemia sebiAspergillus chevalieri, Aspergillus candidus,

Aspergillus ochraceus, Aspergillus versicolor,and Aspergillus nidulans

Aspergillus flavus, Aspergillus versicolor,Penicillium citreoviride, and Penicillium citrinum

Aspergillus oryzae, Aspergillus fumigatus,Aspergillus niger, Penicillium notatum,Penicillium islandicum, and Penicillium urticae

Yeasts, bacteria, and many molds

0.65–0.700.70–0.750.75–0.80

0.80–0.85

0.85–0.90

0.95–1.00

Source: ICMSF. Microbiological Ecology of Foods. Academic Press, New York (1980).With permission.

TABLE 5.2

Moisture Requirements of Common Fungi

Water Requirement Common Indoor Fungi Typical Sites

Hydrophilic fungi(>90% minimum)

Fusarium, Rhizopus, andStachybotrys

Wet wallboard, waterreservoirs for humidifiers,and drip pans

Mesophilic fungi(80% to 90% minimum)

Altemaria, Epicoccum,Ulocladium, Cladosporium,Aspergillus versicolor

Damp wallboard and fabrics

Xerotolerant(<80% minimum)

Eurotium (Aspergillus glaucus group), and somePeni cillium species

Relatively dry materials(e.g., house dust where highrelative humidity)

Xerophilic fungi(<80% preferred)

Aspergillus restrictus Very dry and high sugarfoods and building materials

Source: ACGIH. Bioaerosols. ACGIH, Cincinnati, Ohio (1999). With permission.


(e.g., refrigeration), and some thrive at temperatures in excess of 100°F (e.g.,hot tubs). Although most spores favor moderate temperatures, the inves-tigator should be aware of the potential for growth and amplification ofmolds in just about any temperature setting. The ranges are presented inTable 5.3.

Fungi tend to grow more during months when the humidity and tempera-ture are elevated. In some regions, the peak mold spore season is in the spring,followed by the summer months. Other areas of the country experience peakperiods in the fall. The winter months typically provide the least accommodat-ing conditions for fungal growth. Although the daily and monthly variability isbased entirely on humidity and temperature, growth will increase or decreaseat certain hours of the day or night regardless of the outdoor climate.

Many, not all, fungi have peak growth times that are genus, sometimesspecies, dependent. Some peak in the late of night (e.g., Cladosporium andEpicoccum). Others peak in the early morning. Some peak in the late after-noon (e.g., Alternaria and Penicillium). A few peak, irrespective of time frame,immediately after a heavy rainfall.3 Studies vary on their opinion as to thesetimes, yet they all agree that peak periods do exist.

Indoor air environments may vary in humidity content of the air alongwith the outdoor air environment, and peak mold seasons may correlate tothe indoor environment, particularly where humidity controls are not main-tained. High humidity (greater than 60 percent relative humidity) is thoughtto be the leading cause of fungal amplification within buildings.

Other means of mold spore amplification include, but are not limited to: (1)settled water sources (e.g., air handling system drip pans); (2) damp buildingmaterials (e.g., wet ceiling tiles); (3) air movement from a hot, humid crawlspace into an occupied office area; (4) disturbances of settled dust (e.g., drydusting); and (5) poor vacuum cleaner filtration. It should also be noted thatmushrooms have been identified in buildings where water-damaged carpet-ing has been left uncorrected and other areas where there is an accumulationof water (e.g., behind leaking washing machines).

Molds grow in wide ranges of pH. Although a pH of 5 to 6 is favored bymost, some molds proliferate between pH 2.2 and 9.6. Rare forms have beenfound consuming nutrient impurities found in bottles of sulfuric acid.

TABLE 5.3

Temperature Relations of Common Mold Species

Temperature to Kill Most “Mold Spores” (within 30 Minutes)

Maximum growth temperatures 86–104°FOptimum growth temperature 72–90°FMinimum growth temperature 41–50°F

Source: Crissey, J.T., H. Lang, and L. Parish. Manual of Medical Mycology. Blackwell Science (1995). With permission.


As fungi typically require oxygen, they tend to grow in oxygen rich envi-ronments (e.g., air handling systems). Some, however, grow quite well inenclosed areas where the oxygen may be minimal (e.g., between vinyl wallcoverings and the wall). Yet they all do require some oxygen. There are noanaerobic fungi.

FIGURE 5.1Photomicrographs of allergenic molds with their growth structures. They are: Penicillium spp.(top left), Scopulariopsis spp. (top right), Verticillium (middle left), Alternaria (middle right), andAspergillus niger (bottom left). Mold structures and spores stained, photos taken under 1000Xoil immersion. Photomicro graphs courtesy of Sean P. Abbott, PhD, Natural Sink Mold Lab.


Yeasts

Yeasts, one-celled fungi, are usually spherical, oval, tube-shaped, or cylin-drical in shape. They usually do not form filamentous hyphae or mycelium.A population of yeast cells remains a collection of single cells or buddingstructures. See Figure 5.2. They can be differentiated from bacteria only intheir size and internal morphology (with an obvious presence of internal cellstructures). Some of the yeasts reproduce sexually. The sexual reproductiveprocess forms an ascospore that is resistant to many environmental condi-tions. They tend to grow on nutrient agar intended for molds, and they aregenerally reported along with the molds on a cultured sample.

Yeasts usually flourish in habitats where sugars are present (e.g., fruits, flow-ers, and the bark of trees). The most important ones are the baker’s and beerbrewer’s yeasts. These have been selected and manipulated by man. They donot serve as good representatives of the classification. They are atypical.

Although not common, yeasts have been reported growing indoors onwet, rotting wood and other high moisture content surfaces. When thisoccurs, the indoor yeast levels may exceed the outdoor levels. This is, how-ever, rare. Those that are routinely found in indoor air quality investigationsare Rhodotorula (shiny pink colonies on malt extract agar) and Sporobolomyces(salmon-pink or red colonies on malt extract agar). Cryptococcus neoformans isa pathogenic yeast that produces a thick protective capsule.5

Bacteria5

Bacteria are single-celled organisms ranging in size from 0.8 to 5 microns indiameter. Their surface structure is complex, and they are limited in form.They may appear as spheres (e.g., cocci), straight rods (e.g., bacilli), or spiralrods (e.g., spirochetes), or branched filaments (referred to as actinomycetes).

Some bacteria produce endospores, or internal spores, which are resistantto environmental stresses. Endospores may be allergenic, and they may sur-vive harsh conditions for extended periods. During this dormant period,

Budding Cells

(a) (b) (c)

FIGURE 5.2Yeasts RhoIdotorula (a), SporoboIlomyces (b), and capsulated Cryptococcus neoformans (c).


endospores remain viable and allergenic. They can remain dormant for years.The most commonly known endospore-producing bacterium is the genusBacillus, some species of which are also pathogenic. Actinomycetes normallyproduce spores that are readily released into the environment without theneed for environmental stressors.

Both Bacillus and actinomycete bacteria can be allergenic, and they requiredifferent nutrient agar than that required by molds. They require specialmedia and some actinomycetes require elevated incubation temperatures.They are not likely to show up on mold culture plates.

Bacillus

The genus Bacillus is a gram-positive, rod-shaped bacterium that is known toform endospores under stress conditions See Figure 5.3. Bacillus endosporeshave been implicated as a cause of hypersensitivity pneumonitis, and theendospores have been found indoors as well as outdoors.

Bacillus bacteria thrive on dead or decaying organic material. The sporesare normally found in soil, dust, and water. They can also be found in drydesert sands, hot springs, arctic soils and water, pasteurized milk, storedvegetables, various foodstuffs, and feces.

As the most common concern is typically molds, bacterial endospores areoften overlooked during indoor air investigations. For this reason, there hasbeen minimum research and publications regarding this topic. Some havespeculated that high levels of Bacillus in indoor air is a barometer of pastconditions. Either the HVAC system or the building was subject to extremewater damage, saturation, or lack of maintenance.

Although some species of Bacillus are lethal (e.g., Bacillus anthracis), mostBacillus bacteria are not pathogenic and are rarely associated with disease.The greatest concern herein is allergenicity.

Bacteria Endospores

FIGURE 5.3Bacillus rod-shaped bacteria and oval endospores.


Thermophilic Actinomycetes

Actinomycetes are filamentous bacteria that resemble fungi in their colonialmorphology and production of allergenic spores. See Figure 5.4. Under themicroscope, colonial masses appear as thin hyphae (generally much thinnerthan those found in fungi) with associated spores that are at the low size rangefor fungal spores.

Ideal temperature preferences range from 25°C to 60°C. Yet these rangesmay at times be narrow and highly selective. Thermoactinomyces candidusgrows rapidly between 55°C and 60°C but will not grow at 37°C or less.Although most thermophilic actinomycetes will grow at 37°C, many prefer45°C to 55°C.

Their nutritional requirements are more complex than that of molds, andtheir spores are more temperature resistant. Thermophilic actinomycetesform allergenic spores and can be differentiated from the molds by selectiveculture media and observation of growth patterns.

The most commonly encountered genera are Micropolyspora, Thermo actinomyces, and Saccharomonospora. Some species of Streptomyces have been impli-cated as allergens as well. In nature, these organisms generally require anutritionally rich substrate and elevated temperatures. Ideal habitats includemoldy hay, compost, manure, and other vegetable matter. Indoor amplifica-tion may occur in the heating and humidifying systems where there is alsoa source of nutrients (e.g., vegetable matter buildup in an air handler withelevated temperatures).

Air Sampling Methodologies6

There are no federal government requirements for monitoring nor are thereclearly defined methodologies. Although there have been a few attemptsby professional organizations, universities, and private firms to provide

Spores

Mycelia

FIGURE 5.4Thermophilic actinomycetes are fungus-like bacteria.


guidelines, the most readily accepted guidelines have been set forth by theAmerican Conference of Governmental Industrial Hygienists (ACGIH). Itslatest publication, Bioaerosols: Assessment and Controls, is frequently referencedherein.

Sampling Strategy

The sampling strategy is subject to the investigator’s evaluation of each spe-cific situation. There are a few basic guides to aid the investigator, but theyare not hard and fast rules. Careful thought and planning are paramount.

When and Where to Sample

According to the ACGIH, to anticipate high and low exposures, minimumsampling efforts should include a least one, preferably three, sample areas ineach of the following areas:

• An anticipated high exposure area (e.g., an area identified as centralto health complaints)

• An anticipated low exposure area (e.g., an area identified and con-firmed to have minimum health complaints)

• Outdoors near air intakes for the building (e.g., on the roof or alongthe side of the building where fresh air is taken to supply the indoorarea(s) to be sampled)

Other sample sites that should be included are:

• Outdoors near potential sources of bioaerosols that may enter abuilding (e.g., fresh air entry from open or frequently used doorsand windows downwind from a creek bed or waste container)

• Outdoors high above grade and away from potential bioaerosolsources (e.g., background levels not affected by the immediate build-ing environment)

When assessing fungal growth contributions from a ventilation system,locate a site near one of the air diffusers associated with the air handlingunit in question. Then take samples at different times during the unit’s cycle.Consider the following:

• After the air handling unit has been turned off (generally occur-ring over a weekend), preferably prior to restart after a weekend ofdown time

• After the air handling unit has been turned on, restarted after aweekend


• After the air handling unit has been operating for 30 minutes• During mechanical agitation of the ductwork, preferably when a

space is unoccupied and in a fashion to simulate normal mainte-nance activities or other normal disturbances that might occur to theduct work

Equipment

Although there are several possible choices for sampling equipment, selec-tion is situation dependent. No single sampler can meet all needs. The choicemay be a combination of accessibility, reliability, and functionality, or it maybe familiarity.

SlittoAgar Impactor

The slit impaction sampler operates by rotating a culture plate below a long,narrow slit, or inlet. The collection substrate may remain stationary, movecontinuously, or move in increments beneath the slit.

An internal pump draws air through the slit at a flow rate of 50 liters perminute, and the air is impacted onto 10- or 15-centimeter diameter plateswith nutrient agar. Sampling duration may be from 1 to 60 minutes.

An advantage to this technique is that slit-to-agar impactors have a widerange of detection and provide limited time-differential information. A dis-advantage is that is they are not as readily recognized as other samplers andhave not been time tested.

Multiple Hole Impactor

The sieve impactor operates by the passage of an air stream through evenlyspaced, machine sized holes. The single-stage Andersen impactor has beentime tested and is the most frequently chosen equipment for viable microbesampling.

A high-volume pump draws air through the impactor at a flow rate of28.3 liters per minute, or 1 cubic foot per minute. At this preset flow rate,particles of a given size (e.g., greater than 0.65 micron in size) are depositedonto the surface of a collection medium (e.g., petri dish). Faster flow rateswill result in the deposition of smaller particles and potentially in loss ofviability. Slower flow rates will only deposit larger particles. For this rea-son, it is important that the flow rate be as designed for the most effectivecollection.

A disadvantage is that the samples are limited in duration. A typicalsampling period is from 1 to 5 minutes. Either multiple samples must betaken and averaged over an extended time period (e.g., 8 hours) or randomsampling must be accepted as representative of exposures throughout an


exposure period. Some professionals have monitored for up to 30 minutes.However, there is a risk of oversampling and loss of viability.

Liquid Impingers

Familiarity and simplicity are the principal advantages to the liquid impin-gers. They operate by the passage of an air stream through and inertialimpaction on a liquid. The liquid may be a sterile solution of water (or surfac-tant), mineral oil, or glycerol. The latter two retain the viability of the samplemore effectively than water. All three liquids minimize dehydration.

Do not be confused into thinking a typical industrial hygiene impingerwillwork.Ahigh-volumepumpdrawsair throughaspecialall-glass impinger(AGI) at a flow rate of 12.5 liters per minute. The AGI has a pre-establisheddistance between the tip of the inlet jet to the base of the impinger.

The AGI-4 distance to the base is 4 millimeters, and the AGI-30 distanceis 30 millimeters. Although a more efficient “particle” collector, the AGI-4results in greater physical stress because of its shorter distance to the bot-tom of the impinger. Recovery of viable microbes is more likely with theAGI-30.

Although efficient for collecting a diverse range in particle sizes, thismethod does not have a high recovery efficiency for hydrophobic bacteria(e.g., Bacillus) and some mold spores in water. Recent research, however,indicates effective recoveries in mineral oil and glycerol. Both require con-siderable static pressure to overcome resistance to air movement throughthe fluids and filtration necessary upon receipt by a laboratory. The latteris meeting with considerable resistance due to the difficulty of separatingspores down to 1 micron in size from the viscous liquids.

Upon separation, samples can be diluted and plated onto several differentnutrient agar. This process allows for different media to be inoculated fromthe same sample and may permit greater sampling times than the recom-mended 30 minutes. Yet more experience is needed with the AGI to reach alevel of competency attained by some of the others.

Filtration

Familiarity, simplicity, and long-term sampling are the principal advantagesto the filtration. Although efficient for collecting a diverse range in sporesizes, sample collection and filter clearance have a severe drying effect on thecollected allergens, and analysis results in underestimated spore counts.

Smooth-surfaced filters (e.g., polycarbonate) are less damaging than thecoarser filters, and some of the larger industrial hygiene supply companiesare developing hydrated filters to overcome the drying effect of long-termsampling. The sample airflow rate is 1 to 5 liters per minute.

Sampling duration is variable, up to 24 hours, and air volume may be upto 1000 liters. The higher flow rates and the longer sampling times will result


in even a more extensive loss of spore viability. Filtration is discouraged forthe more fragile bacteria.

Centrifugal Agar Samplers

Longer sampling duration and ease of use are the principal advantages tothe centrifugal agar sampler. It operates by a rotating drum that draws airat a flow rate of 50 liters per minute with impaction of particles onto the sur-face of manufacture supplied agar strips. The sampling duration is up to 20minutes. Although not all laboratories are familiar and capable of analyzingagar strips, this approach is becoming more widespread.

Sample Duration

Equipment, airflow rates, and culture plate limitations are the limiting factorsin sample duration. The most commonly used sampling equipment requiresa sample duration of 1 to 60 minutes, a small snapshot in the overall expo-sure time. Airflow rates are preset, not subject to change, and culture platescan become overloaded if too much air volume is sampled. The sample dura-tion is the only variable that can be adjusted—knowing the limitations.

Ideally, the investigator wants to collect a minimum number of colonyforming units (CFU) with a maximum number of microbial growths perplate. Overloading can render the sample unreadable. Note that some labswill attempt to read overloaded plates and report a greater than number.The ACGIH recommends an optimal collection of 10 to 60 CFU/plate. Yetin order to stay within this range, the investigator must anticipate theexposures.

For example, with a single-stage Andersen impactor, the lower detectionlimit would be 35 CFU/m3 for a 10-minute collection time, and the upperdetection limit would be 5570 CFU/m3 for a 30-second collection time. Onceagain, the sample duration is based on anticipated exposures. Professionaljudgment comes into play!

Sample Numbers

With limited sample durations of less than 10 minutes in most cases and60 minutes in others, monitoring the entire exposure time would requiremultiple samples—an unfeasible proposition. Thus a logical, well-thought-out selection of sampling time(s) is necessary to obtaining results that can bereadily interpreted with minimal speculation.

Either the investigator may choose to sample during an anticipated worstcase scenario (e.g., respondents on questionnaires state that their symptomsare worse on Monday mornings or after custodial activities), or the investiga-tor may choose to take two to three samples at each site throughout the day.Some investigators may choose to sample every other hour throughout theexposure period. Larger sample numbers result in greater data reliability.


Yet on the practical side, larger sample numbers result in greater expense.The decision on the number of samples to be taken becomes a difficult deci-sion of weighing all factors. See Figure 5.1.

Culture Media

There is considerable controversy as to the appropriate medium to use. Notall molds will grow and create recognizable spore-forming structures on asingle nutrient agar. This is one of the single most important and controver-sial issues in sampling for molds.

General Information

The choice of culture medium is dependent upon the organism(s) the investi-gator seeks to identify and on the laboratory’s choice. Keep in mind thatthere is no single medium upon which all fungi or bacteria will grow. Not allcan be cultured, and not all molds will form identifying spores. The failureto form identifying spores is generally reported as nonsporulating coloniesor mycelia sterilia.

The best, most commonly used culture medium for airborne fungi is maltextract agar (MEA). This medium supports the growth of most viable fungalspores, and MEA is an excellent medium for identifying species. Species iden-tification is sometimes important, not only for allergen amplification determi-nation, but for identifying species that may have other effects. For example,Aspergillus flavus can be deadly for immune-suppressed individuals.

Some media inhibit the growth of undesirable competitors. Rose Bengalagar (RBA) is used for fungi while bacterial growth is kept to a minimum. Insome environments where high bacterial levels are anticipated (e.g., agricul-tural environments), RBA would be the medium of choice.

Stachybotrys molds grow on cellulose agar. Although some laboratoriesclaim this medium is best suited for Stachbotrys, some laboratories have dem-onstrated that Rose Bengal agar works equally well. The trend, however, istoward cellulose agar when Stachybotrys mold is the focus.

Bacillus as well as environmental and human commensal bacteria growwell on R2Ac agar with cycloheximide, a fungal suppressant. Bacillus andthermophilic actinomycetes will grow on tryptic soy agar (TSA). Bacillus andpathogenic bacteria will grow well on blood agar (BA). As different speciesgrow in variable temperature ranges, the choice of medium for Bacillus mayalso be dependent upon the anticipated temperature tolerance for the bacte-ria under investigation. In an indoor air quality investigation, the most likelyBacillus to grow will be that which grows at room temperature. In this case,the R2Ac would be the medium of choice.

The preferred medium for thermophilic actinomycetes is tryptic soy agar.The thermophiles grow best at elevated temperatures as do the pathogenicbacteria. Elevated temperatures tend to kill or suppress growth of otherorganisms.


The thermophilic actinomycetes are incubated at 56°C, and the commen-sal bacteria are grown at 35°C. All others are grown at room temperature(i.e., 23 ± 3°C).

Special Comments

Plated culture medium can be purchased from a laboratory supply retailer(e.g., Remel or Difco), and some microbial laboratories supply media to theirclients. The latter is preferred.

For use in impaction samplers, the plated medium should be evenly dis-tributed in the petri dish. If it has melted during transportation and is notlevel upon receipt, do not use the plate. Impaction is based on distance fromthe air holes to the surface of the agar. If the agar is not flat, the impactionwill result in poor sample collection and inconsistent counts.

Culture media dries out after four to six weeks. So don’t overstock.Understocking may pose a problem as well. Order for anticipated needs witha minimum 10 percent excess. Keep in mind, the plastic dishes may crack intransit, or the investigator may inadvertently contaminate a plate (e.g., stick-ing a finger into the agar) and require replacement. The perfect world doesnot exist outside the laboratory.

Equipment must be calibrated to assure adequate flow. This may be up tothe discretion of the investigator. Most investigators do not have adequateequipment for calibration (e.g., large bubble burettes or electronic bubblecalibrators are not adequate). The equipment manufacturer generally offersthis service and recommends calibration at least annually.

Thesampler(s) shouldbedisinfectedbetweensample locations. Isopropanolis the agent of choice at this time. It can be easily purchased and treated, andindividual packets are available for purchase.

Excess cleaner (e.g., isopropanol) should be dried prior to its next use, and thesieve holes should be inspected prior to proceeding. Then allow the sampler torun for a couple minutes—at the new location—prior to taking the next sample.

Care should also be taken with the petri dish cover for the duration of thesampling. A minimum precaution should be to place the cover face down ona clean, smooth surface for the duration of the sampling. To assure a surfaceis clean, wipe the surface with an alcohol swab prior to putting down the topof the petri dish.

After the sample has been taken, replace the cover, seal or tape the edges(e.g., laboratory Parafilm), label the petri dish, and store it with the agar sidedown. Some laboratories prefer ice packs to accompany the samples. Thisallows for the plates to be transported without growth occurring prior toreceipt at the laboratory, but excessive condensation in the plates may beproblematic. The laboratory chosen to perform the sample analyses shouldbe consulted prior to each scheduled sample collection for instructionsas to their in-house procedures for packaging, shipping, and receiving. Ifshipment to a laboratory is required, most laboratories require overnightshipments. For samples that are shipped on a Friday, weekend, or holiday,


special arrangements should be made beforehand. Express delivery servicesavailability and time lags should be determined, and arrangements may beneeded with the laboratory for special deliveries.

When choosing a laboratory, consider in-house procedures for sampleincubation. Suggested incubation for fungi is 10 to 14 days at room tempera-ture with subsequent identification by genera. Some laboratories will per-form a count within 5 to 7 days after receipt. Others feel the slower-growingmolds will take up to 14 days to grow, and a shorter incubation period mayresult in incomplete counts and mold identification. The count can be off asmuch as 10 percent, and an early count may also result in not identifyingsome of the more important, slow-growing molds (e.g., Stachybotrys).

Sample incubation times impact the laboratory turnaround time andcompleteness of information, considerations which may vary depending oneach situation. For example, a quick turnaround is required, and the incu-bation period for a specific targeted mold type is five days. Some laborato-ries will not assess a sample until the full 14 days have passed. So, in somecases, the investigator may want to locate a laboratory that will evaluate thesample(s) earlier. Some do it routinely and this type of laboratory can befound. See Figure 5.5 for petri dish growth samples.

Pathogenic molds will not readily grow on most of the media. They growbest at higher incubation temperatures and require much longer incubationperiods, up to three weeks. If the pathogenic molds could grow at room tem-perature, on the nutrient media provided, the other fungi would likely over-grow the petri dish, and newly formed pathogenic mold colonies would notbe observed.

The recommended incubation for thermophilic actinomycetes is 55°C forfour days. On the other hand, Bacillus bacteria can be incubated within two

TABLE 5.4

Summary of Culture Media and Anticipated Growth Patterns

Culture Media Predominant GrowthIncubation

PeriodIncubation

Temperature

Malt extract agar fungi 1–2 weeks RTRose Bengal agar(suppresses bacteria)

fungi 1–2 weeks RT

Cellulose agar Stachybotrys fungi 1–2 weeks RTR2Ac agar environmental bacteria 48 hours RTTryptic soy agar Thermophilic

actinomycetes andBacillus

48 hours 56°C

Blood agar pathogenic andcommensal bacteria

48 hours 35°C

MacConkey’s agar Gram negative bacteriaand E. coli

48 hours 35°C

Note: RT = room temperature.


(a)

(b)

(c)

FIGURE 5.5Petri dish deposition using impaction samplers. Examples are: (a) impaction marks on agar, (b)culture with count of 1761 CFU/minute on malt extract agar after five days of incubation, and(c) excessive growth on malt extract agar after five days of incubation.


to four days along with the thermophiles on the same nutrient medium at55°C, and Bacillus bacteria can be incubated in two days at room temperatureon the same nutrient media as the thermophiles or on a different medium.The different incubation temperatures are important for identification of allBacillus genera. If Bacillus bacteria are amplified and contributing to the totalmicrobial allergens, the most likely Bacillus species to be found amplifiedindoors would be those that grow at room temperature.

For quality control, some investigators collect a blank along with the airsamples. The blank may be an unopened or opened petri dish. The unopenedblank may provide information as to whether the nutrient medium has beencontaminated prior to sampling or during shipping. The opened blank maygive information as to the investigator’s sample handling procedures. Not cur-rently a common practice, the submittal of blanks is gaining in popularity.

Procedural Summary

Determine a sampling strategy, when and where to sample. Get the appropri-ate equipment, and collect the sample(s) with caution. Precautions shouldbe taken not to contaminate media by: (1) properly cleaning the equipmentbetween sample locations; (2) proper management of the sampling media;and (3) proper shipping.

Collect each sample, label containers (e.g., alpha numeric), and log thesample location details as well as air volume sampled or duration of sam-pling. Additional information the investigator may want to enter is obser-vations (e.g., sample taken immediately under a recently opened ceilingtile), environmental conditions (e.g., relative humidity and temperature),air movement (e.g., directly in line with an air supply diffuser that wasblowing at the time of sampling or measured air movement 200 feet perminute at sample location), and odors (e.g., a site identified as having strongmildew odors).

Package all samples in a sturdy container. Some laboratories request spe-cial packing procedures (e.g., ship in Styrofoam™ container with ice pack).Ship for overnight delivery to an analytical laboratory.

Diagnostic Sampling Methodologies

Oftentimes, it becomes necessary to identify the source of amplified microbes.Either remediation of a suspected source has failed to rectify a problem, orthe environmental professional chooses to confirm suspect sources at thetime of the initial sample taking, possibly after obtaining the initial air sam-ple results and prior to making recommendations. Bulk and surface sam-pling is the recommended approach.


Sampling Strategy

Purpose is the focus when developing a sampling strategy. Bulk and surfacesampling may be performed for any of the following reasons:

• To confirm or deny a suspect source of mold growth• To identify sources of potential airborne microbes• To confirm adequate cleanup

If a surface has visible staining, the discoloration may or may not be molds.Surface sampling can be performed not only to confirm or deny its pres-ence but to identify the type of mold. A dark black stain that appears to be amold on a wall surface may be charred grease or shredded rubber, or a blackgraphitelike material on the wall may be a specific identifiable mold.

Molds are often found growing on wet fiberglass duct insulation immedi-ately after the cooling coils. This is a common finding, and surface samplingis vital to confirm the presence of molds where expensive remediation may beinvolved.

Duct-cleaning services and some investigators confirm molds in the rela-tively dry ducting and use its mere presence to justify cleaning the air duct-ing. It is no surprise that these same people always do find molds in theair ducts and subsequently require extensive duct cleaning. The investigatorshould not rely on surface and bulk samples alone because

… bulk samples cannot replace air samples because the former have notbeen found to accurately reflect past, future, or even current bioaerosols.7

Once air sampling has been performed and amplification of certainmolds confirmed, the investigator should locate the source. Cleanup canbe very expensive, and identification of the source can be vital not onlyto limit the cleanup but to assure that the actual source has been locatedand remediated.

After remediation and cleanup of an area, surface sampling may be per-formed to confirm adequate cleaning. This is a secondary approach after avisual inspection has been performed and all surfaces appear to be clean.

Where to Sample

Once the purpose has been defined, the investigator performs a visualinspection of the area or areas of concern. If microbial growth is apparent, asufficient number of samples should be taken to represent all suspect com-ponents. For instance, if wet duct insulation has a large surface area withthick brown mudlike splotches, a black-green patch, and several white spots,one of each of the three different sites should be taken.

If microbial growth is not apparent, the investigator may either performseveral random samples or identify suspect areas based on area activities,


interviews, and the presence of moisture/growth media. Custodial or main-tenance personnel may have been observed working above ceiling tiles inthe complaint area. Carpeting and partition panels may harbor molds but nothave a visible presence. Settled water may be contaminated with microbesbut not have any visible evidence as to its presence.

When deciding where to sample, the investigator should focus on the fol-lowing points:

• Microbial growth is influenced by temperature and humidity.• Dissemination of microbial allergens is influenced by activities (e.g.,

vacuum cleaners may disperse molds into the air), the presence ofmolds (e.g., excessive dust collection), and air movement over sur-faces (e.g., inside air ducts).

Upon confirmation as to the presence of high moisture content in walls,some investigators actually put a hole into the wall in order to take a sampleof a suspect microbial growth surface and, upon identification of its pres-ence, spend great sums of money remediating wall spaces that contain moldspores, with no evidence of airborne spores. Although it is possible to haveair movement within the wall spaces and entry of wall contaminants intooccupied spaces through wall penetrations (e.g., wall sockets), these consid-erations are rarely tested.

The greater the number of samples taken, the more reliable the statisti-cal end product. Yet larger sample numbers are more expensive. All factorsshould be taken into consideration.

What to Sample

Microbes can be found in or on almost anything. Thus the investigator shouldbe prepared to interpret findings prior to sampling. Taking samples withouta game plan can result in a conclusion with strange bedfellows.

Samples can be taken of surfaces or suspect bulk materials. Surface sam-pling may involve loose surface debris and dust, and bulk sampling mayinvolve a substrate and its component debris and dust. The substrate may bea porous solid material (e.g., carpeting or fabric office partition), or it may bea liquid (e.g., water in a drip pan).

Yeasts and molds may grow in flower pots. These are areas often over-looked. Where suspect, soils may also be sampled.

Sampling Supplies

The equipment needed for surface and bulk sampling is less involved thanair sampling. Although the equipment can often be purchased at a localgrocery or drug store, the analytical laboratory should be consulted prior toobtaining supplies. They may prefer their own sterile supplies or may have


developed detailed directions and protocols. Many laboratories will sendthe appropriate supplies upon request.

Surface sampling is often done by wipe (i.e., swipe) sampling or dust collec-tion. Wipe sampling is performed using a sterile swab that can be returnedto a sterile container after a sample is taken. In some cases, the container willhave a wetting solution in an ampoule that is broken to release a wettingagent onto the surface of the swab (e.g., 3M Quick Swab). However, somelaboratories prefer the investigator use dry swabs.

Dust, debris, and soil can be collected in plastic ziplock bags, capped vials,or filters (e.g., cassettes) with a suction device (e.g., air sampling pump).Water samples can be collected in capped vials, and moist surface areas maybe sampled with a swab.

A sterile template is advisable for swipe sampling. Some laboratoriessupply a prepackaged plastic 4-inch by 4-inch template. The template pro-vides boundaries within which a sample may be taken and surface areareported.

Bulk sampling requires a sterile container, cutting tool, and latex gloves.Larger samples will require larger containers, and if an abundance ofmicrobes is anticipated, sterile containers may become a moot point.

Procedural Summary

Determine a sampling strategy, where to sample, and what to sample. Get theappropriate supplies and collect the samples without cross-contaminatingeach new sample. Cross-contamination may occur by unprotected hands anduncleaned implements (e.g., template or utility knife).

Collect each sample, label containers (e.g., alpha numeric), and log thesample location details as well as surface area or size/volume of the bulkmaterial. Additional information the investigator may want to enter is visiblesurface area affected (e.g., visible coverage on approximately 20 square feet),environmental conditions (e.g., wet duct insulation, high humidity, and tem-perature), and description of stained material (e.g., tea-colored ceiling tiles).

Package all samples so cross-contamination, penetrations, and damagecannot occur during shipping. Ship perishable samples by overnight deliv-ery to an analytical laboratory.


The interpretation of results is highly controversial. Attempts have been madeby various researchers and professional groups to set exposure limits for aller-genic spores, but environments, exposure durations, predisposing health con-ditions, and limitations of viable sampling add fuel to an already heated topic.


Office, agriculture, school, and residential environments will vary consid-erably in anticipated exposure levels and in tolerance. Anticipated exposuresto agriculture workers are quite high, whereas office exposures are generallyless than 200 CFU/m3. See Table 5.5.

Office personnel and agriculture workers are typically healthy adults, andtheir exposures are limited to workday hours. Yet even in this group thereare people who are more sensitive to allergens than others (e.g., asthmat-ics). School children have more allergies than adults. They grow out of theseallergies as they get older, but they are exposed to all sorts of allergens intheir school environments. Residential exposures include infants, elderlypeople, and adults with debilitating health conditions, and their exposuresmay be ongoing, 24 hours a day, seven days a week. Setting one limit toaccommodate all is not feasible.

The other problem with establishing an exposure limit for viable microbialallergens is that the count may not be representative of all microbial allergens.All microbial allergens include viable, culturable, and nonculturable microbes.The information derived from viable microbial allergens may be only a smallportion of the offending allergens. Although not always applicable, the infor-mation derived from viable microbial sampling often needs to be assessed byother means. To date, the most recognized approach to defining environmen-tal problems as they relate to microbial allergens is the assessment of genusvariability, a process that has as many approaches as there are investigators.

Genus Variability

Genus variability involves genus identification and percent of total compo-nents. The indoor complaint area is compared to the outdoor area and some-times to a noncomplaint area as well. Where there is a shift in the percent of

TABLE 5.5

Concentrations of Viable Allergens in Agricultural Environments

Workplace Environment Thermophilic Actinomycetes Total Fungi

Outside air 10 1,000Domestic waste management 1,000 100,000a

Farming (normal activities) — 10,000,000Farming (handling moldy hay) 1,000,000,000 1,000,000,000b

Pig farms 1,000 10,000Mushroom farms (composting) 10,000,000 100Mushroom farms (picking) 100 100Sugar beet processing 100 1,000Cotton mills 100,000 1,000

a Mostly Aspergillus and Penicillium.b Mostly Aspergillus.Excerpted from Crook, B.8


identified components in the indoor air versus the outdoor air, indoor ampli-fication (or growth on a building material) is indicated. A shift in the percentis interpreted in several different ways.

The most common approach is to assess percent of total microbial aller-gens. For instance, the outside air may contain 85 percent of Cladosporium,10 percent of Alternaria, and 5 percent Penicillium, and the indoor air may con-tain 90 percent Peni cillium, 8 percent Cladosporium, and 2 percent Altemaria.This example, involving unrealistically limited numbers of mold spores in atotal count, is a good indicator that Penicillium molds are growing indoors.

Some investigators generate a graph of the more realistic 10 to 12 identifiedmolds and compare these. This approach is not as easy to assess as where thetop two or three identified molds are compared without the complex jumbleof all molds.

Some investigators do not perform a genus variability assessment wherethe total count is low (e.g., less than 100 CFU/m3). A low colony count issubject to considerable variability. The collection of only a few spores in asmall air volume can vary a lot due to natural variability of air samples andsampling or analytical errors. The statistical variability due to these factorshas yet to be published for viable mold sampling methodologies.

Amplification is often considered where certain toxigenic molds are identi-fied indoor, irrespective of that identified outdoors. Stachybotrys is one suchmold. Be wary, however, of declaring amplification where there is a singlecolony of a given mold. A single colony may be an anomaly that occasionallyoccurs in outdoor air samples as well.

The assessment may also be limited by the laboratory reporting techniques.Most laboratories identify the more prevalent genera, up to a limited number(e.g., five of the most numerous mold colonies). Some identify all recogniz-able genera on the basis of growth structure and patterns, whereas othersidentify the most prevalent genera. Many will attempt to identify speciesof Aspergillus as well (e.g., Aspergil lus flavus). Other genera must be replatedfor species determination. This involves more expense and culturing time(e.g., an additional two weeks). A fungal colony may be declared as uniden-tifiable, or if it fails to produce sporulating structures in culture, is referredto as a nonsporulating colony or mycelia sterilia. The latter means that themold is sterile and does not form fruiting bodies (e.g., reproductive spores)in the particular nutrient media provided by the laboratory. The mycelia can,however, be replated onto other media where they may grow and potentiallybe identified. Due to recent concerns, most laboratories will also identify themost common species of Stachbotrys (i.e., Stachybotrys chartarum). The sameinterpretation process should apply for thermophilic actinomycetes andBacillus bacteria as well. Separate sample culture media and analytical tech-niques are required for bacterial isolation and identification.

Prior to 1999, ACGIH publications recommended numeric exposure limits.These have since become obsolete, but some investigators persist in demandsfor airborne exposure limits.


Airborne Exposure Levels

Reports indicate that outdoor spore counts routinely exceed 1000 counts/m3

and may average near 10,000 counts/m3 during warmer, more humid months.In some parts of the country, the outdoor levels may exceed 20,000 counts/m3.The levels vary throughout the day and only a percent of these are viable.

With rare exception, indoor levels of allergenic molds that are less than100 CFU/m3 are not typically associated with complaints. Exceptions includespecial environments, such as hospitals, where there are immune-suppressedpatients that must avoid any level of certain molds (e.g., Aspergillus flavus)and people with life-threatening respiratory problems.

Some environmental professionals chose 200 CFU/m3 viable molds as theminimum indicator for probable indoor exposure limits in environmentswith a relatively healthy adult population (e.g., office buildings). The previ-ous ACGIH recommended limits were even more permissive.

In 1986, the ACGIH recommended a limit of 10,000 CFU/m3 total fungi,500 CFU/m3 for one genus of mold, and 500 CFU/m3 for thermophilic actino-mycetes. In 1989, they recommended comparative sampling and stated thatthe presence of thermophilic actinomycetes, typically associated with agri-cultural environments, is sufficient to indicate contamination.

While comparison sampling has become a sound scientific approach forascertaining amplification, viable sampling provides only a piece of the pic-ture. An easily referenced standard for acceptable mold and bacteria sporelevels is not just over the horizon.

Bulk and Surface Sample Results

The laboratory reports bulk samples in terms of identified viable microbialnumbers per weight or volume of material. This is usually in terms of CFU/gram or CFU/milliliter.

Surface sample results are reported based on the identified viable micro-bial numbers per surface area. This is typically done in terms of CFU/cm2

or CFU/inch2.Although the numbers may appear quite high to an investigator (e.g.,

2,000,000 CFU/gram), there are currently no guidelines to assist in theassessment of these levels. Poor numerical correlation exists between bulkand surface sample results, although species identification of molds growingon surfaces within buildings can be directly compared to species identifiedin air samples. Thus the best use for the results is identification of probablesources that result in amplification of allergenic microbes indoors.

For example, if there was 43 percent Aspergillus sydowii indoors and none inthe outdoor air sample, and 100 percent Aspergillus sydowii in a bulk sample,the bulk sample location is immediately suspect of being the source or oneof the sources of amplified airborne mold spores. If the bulk sample had con-tained Aspergillus versicolor (and was not found in the air sample), the samplesite would not be suspect. This is where species identification can be helpful.


Although they may have the same mold types, surface area samples willtypically be in smaller numbers than those analyzed by weight. For instance,duct insulation may have 2,140,000 CFU/gram (and 100 percent Penicillium)with a surface level of 2 CFU/cm2. An attempt to interpret the numbers canbe a daunting task. However, it is clear that most of the contaminant is deepwithin the porous surface of the duct insulation.

Helpful Hints

When taking short-term samples, either use a stop watch, a timer with asecond hand, or an in-line timer that will turn off the sampler. One- andtwo-minute samples that go over by 10 or 15 seconds can make a big differ-ence in the calculated air volume and final results if not reported. If you goover, either report the air volume on the basis of the time sampled in termsof minutes and seconds or start over.

It is also distinctly possible, perhaps inevitable, that the investigator willat some time poke his or her finger in the sterile nutrient agar. Once compro-mised, the plate should be discarded. Start over again.

As a level of confidence is reached, the investigator will typically chooseone sampler and stay with it. While this is a prudent practice, other methodsthat may meet more expanded needs are constantly being improved andrefined. Many approaches are tried and true, but new technology emergesevery day. The investigator may follow the progress of new technologythrough professional journals, conferences, and publications.

Summary

Viable microbial allergens include molds and spore-forming bacteria. Yetviable is the key word. All airborne microbial allergens may not grow on thenutrient media used for air sampling. For this reason, a count is often ques-tioned. The primary information the investigator needs to target is the com-parative sampling (i.e., comparison of complaint, noncomplaint, and outdoorsamples). Then, too, if the sampling strategy and methodologies are poorlyplanned and executed, the results can be difficult, if not impossible, to assess.

Diagnostic sampling can be invaluable if performed methodically with aclear concept of what one is looking for. Sampling for sampling’s sake willgo nowhere.

Viable microbial sampling is best used in conjunction with pollen/fungalspore counts. In one situation, the fungal spore counts had an elevated


anomaly the laboratory wanted to call Aspergillus/Penicillium. Two weekslater as the viable results became available, the count was low and theanomaly turned out to be oil droplets. Viable sampling does have a place inobtaining information.

References

1. ICMSF. Microbiological Ecology of Foods. Academic Press, New York (1980).2. ACGIH. Bioaerosols. ACGIH, Cincinnati, (1999), p. 19–6.3. Crissey, J.T., H. Lang, and L. Parish. Manual of Medical Mycology. Blackwell

Science (1995), pp. 190–201.4. Al-Doory, Y., and J. Domson. Mould Allergy. Lea & Febiger, Philadelphia (1984),

pp. 36–37.5. Jaeger, Deborah, L., M.S. et al. Microbes in the Indoor Environment. PathCon

Laboratories, Norcross, Georgia (1998).6. ACGIH. Bioaerosols. ACGIH, Cincinnati (1999).7. Ibid, pp. 12–3.8. Crook, B., and J. Lacey. Airborne Allergic Microorganisms Associated with

Mushroom Cultivation. Grana. 30:445 (1991).

93

6PathogenicMicrobes

In indoor air quality investigations, pathogenic microbes are disease-causingfungi and bacteria to which building occupants are most likely exposed.Although a proactive approach to problem identification is desirable, expo-sures to pathogens and toxic microbes are a rare concern in indoor environ-ments unless a large number of associated illnesses are reported.

Sampling requires lengthy culture times, complicated by the presence ofother environmental, nonpathogenic microbes that may mask and preventidentification of the pathogen by over-growing the culture medium. Then,when a suspect colony is isolated, additional time is required to performmore extensive, complicated analyses/cultures in order to confirm its iden-tity and, in many cases, to determine the species and strain.

Whereas many of the pathogens are potentially lethal, the time requiredfor identification is frequently not practical. For this reason, the presence of apathogen is often assumed where patients are symptomatic or reacted uponlater. Typically, health professionals attempt to isolate the source environ-ment through studying sick patients’ habits and environmental associations,trying to recreate a common denominator for an observed epidemic.

Although pathogenic diseases are frequently occupation and area depen-dent, the greatest attention to pathogen spread occurs in hospitals. Aninfected patient aerosolizes (e.g., coughs or sneezes) viable pathogens, andimmune-suppressed patients are particularly susceptible to aerosolizedpathogenic and normally nonpathogenic microbes. Immune-suppressedpatients include those with AIDS, organ transplants, chemotherapy treat-ments, and diabetes. Operating rooms and invasive diagnostic testing areasare possibly involved. Infants and the elderly can be compromised.

Those weakened by living conditions (e.g., the homeless) and inadequatenourishment (e.g., Somalians) exhibit an enhanced susceptibility to patho-gens. Then, too, some pathogenic microorganisms are capable of causingdisease in healthy individuals under special circumstances. Contaminatedintravenous solutions and hospital implements provide an easy avenue forentry. Puncture wounds in contaminated environments are fertile soil, anddamaged tissues propagate invasive challenges. Opportunity for pathogenicassaults is subsequently dependent upon the environment.

Some pathogens multiply in air handlers and water reservoirs. Many arecontained within environmental dust. The problems are rarely identified


prior to the spread of disease to others associated with the dispersing mecha-nism. Sampling is generally requested after a problem has arisen. Proactivesampling in environments where specific pathogens may thrive is indicated.

As invasion and amplification require viable pathogens, the best samplingis for viables. However, viable samples require lengthy culture times, longperiods of time not always prudent in a potentially lethal environment.

Methods are available that can identify some pathogens rapidly and accu-rately. However, these methods identify nonviable and noninvasive microbes.They are limited, and the results are sometimes difficult to interpret. Yet theinformation is provided herein should an investigator require rapid process-ing until more reliable information can be provided at a later date.

Airborne Pathogenic Fungi1–3

Pathogenic fungi are those fungi that cause disease through inhalation ofairborne spores (e.g., Histoplasma capsulatum) as well as potentially causingdisease in immune-suppressed patients and individuals with skin surfacedamage (e.g., Aspergillus flavus). Skin surface damage may include wounds,open sores, cuts, abrasions, burns, and dry cracks. Symptoms of fungal dis-ease range from localized surface discomfort to whole body invasion, andoccasionally death.

The primary focus of this section is to discuss the airborne fungi that caninvade and cause death. Only the principal pathogenic molds are discussed.Those that are infrequently or not typically found in the United States mayrequire additional research, strategy, and sampling development. The fol-lowing information should provide direction and guidance to addressingpotentially lethal environmental situations.

Disease and Occurrence

Understanding the diseases caused by specific pathogenic fungi and regions/areas where they primarily occur is necessary to determine a need for sam-pling. At the same time, however, the environmental professional must not belimited by this information. An outbreak may occur when least expected.

Aspergillus

Several species of Aspergillius, primarily Aspergillus fumigatus and flavus,can cause a disease commonly referred to as aspergillosis. As the genusAspergillus is one of the more common fungal spores found in air monitoring,the pathogenicity is minimal, unless an individual is immune suppressed or

PathogenicMicrobes 95

has a debilitating illness. The initial symptoms may be localized to the lungs,ears, or perinasal sinuses. Once the fungus has found a place to grow, thehyphae may grow into the bloodstream to deposit spores to be disseminatedto other parts of the body. The result may be the formation of abscesses orgranulomas in the brain, heart, kidney, and spleen.

As Aspergillus fumigatus and flavus thrive in immune-suppressed patients,the greatest areas of concern are in the hospitals, clinics, nursing homes, andhospices. Immune-suppressed patients include AIDS patients, organ trans-plant patients (e.g., heart transplants), premature infants, and radiologicallytreated leukemia patients. Invasive diagnostic suites and operating roomsare particularly critical. The presence of even low levels of the invasive formsof certain Aspergillus species can be deadly. The hospitals seek to controlthese environments. See Table 6.1 for historic outbreaks.

Some studies have included several fungal species to the list of potentialinvaders. One such study includes the following:4

• Aspergillus fumigatus

• Aspergillus flavus (also producer of the carcinogen aflatoxin)• Aspergillus niger

TABLE 6.1

Historic Outbreaks of Nosocomial Aspergilliosis

Number of Patients Type of Disease Host Environmental Factors

7 (not identified) bone marrow transplants recent construction anddefective air conditioner

32 pneumonia/sinusitis respiratory patients building constructionand defective AHUsand colonization

10 invasive pulmonarydisease

immunosuppressed (7),malignancy (2), elderly (1)

road construction anddefective air conditioners

9 invasive pulmonarydisease

— building construction

3 invasive pulmonarydisease (2) andcolonization (1)

renal transplants hospital renovation

8 invasive pulmonarydisease with onedissemination

acute hematological wet fireproofing and duston false ceiling;malignancy, neutropenia

4 invasive pulmonarydisease with onedissemination

renal transplantation,immunosuppressive drugs

pigeon excreta externalthrough the air intake

Note: Numbers in parentheses are breakdown of host patients from first column.Source: Cross, A.S. Journal of Nosocomial Infection. 4(2):6–9 (1985). With permission.


• Aspergillus terreus

• Pseudallescheria boydii

• Fusarium spp.

• Mucoraceae spp.

• Phoma spp.

• Alternaria spp.

• Penicillium spp.

Other studies include Zygomycetes and Rhizopus.5, 6 Most agree, despite thefailed concurrence of opinions, that Aspergillus fumigatus and flavus are thepredominant fungal spores of concern in hospitals. The other species shouldbe considered “potentially invasive” by the environmental professional.

There are a few occupational exposure concerns regarding the genusAspergillus as well. Aspergillosis was first described by an Italian in the 1700sas an occupational disease of people who handled grains and birds.

This concern, however, has lost its significance in modern times. As thefungus grows best on compost and damp organic matter, farmers and fieldworkers are a potential risk for high airborne exposures to Aspergillus.

Histoplasma capsulatum

Histoplasmosis, caused by inhalation of the mold spores of Histoplasmoa capsulatum, results in a variety of clinical manifestations. Primary histoplas-mosis is a common, region-oriented, benign disease of the lungs involving amild or asymptomatic pulmonary infection with a cough, fever, and malaise.Chronic cases may go on to experience a productive cough, low-grade fever,and a chest X-ray showing cavitation. As the cavitation resembles tuberculo-sis, however, many cases are misdiagnosed. Then, a small percent (less than1 percent of all cases) of those showing symptoms develop in the progressiveform that can be lethal.

Progressive, systemic histoplasmosis is less common. It is characterizedby emaciation, leukopenia, secondary anemia, and irregular pyrexia. Thereis frequently ulceration of the naso-oral-pharyngeal cavities and intestines,with generalized infection of the lymph nodes, spleen, and liver.

There have been reports of Histoplasma capsulatum related chronic menin-gitis in nonimmune-suppressed hosts, and some have speculated that thefungus also contributes to persistent or recurrent carpal tunnel syndrome.8, 9

Symptoms in immune-suppressed patients are highly variable, and the fun-gus is generally associated with other pathogens.

Within the United States, Histoplasma capsulatum is endemic in the CentralMississippi Valley, Ohio Valley, and along the Appalachian Mountains.See Figure 6.1. Other endemic areas include sections of South America andCentral America, and there are occasional outbreaks in various parts ofthe country and world. It is thought that the spores become airborne and


Sampling should include soil and dust samples from occupational or resi-dential environments in regions endemic with Coccidioides immitis. With afew minor exceptions, the sampling methodology for this fungus is similarto that of Histoplasma capsulatum.

Cryptococcus neoformans

Cryptococcus neoformans attacks the central nervous system, producing sub-acute or chronic meningitis. It may also impact the lung tissue and causelow-grade inflammatory lesions that may be mistaken for tuberculosis or aneoplasm. Occasional cases arise whereby the fungus gives rise to localizednodular lesions of the skin or generalized infections with lesions of the skin,bones, and viscera.

Rare in healthy adults, Cryptococcus neoformans varieties neoformans andgattii are reported to be the cause of death in 6 percent to 10 percent of the HIVpatients. Thus they are among the most common AIDS-related, lethal myco-ses.11 These strains have been known to cause blindness in AIDS patientsand are the foremost cause of central nervous system infections in the same.Diabetics, cancer patients, and recipients of organ transplant patients are atrisk of generalized infection. Fungal infections range from 5 percent in recip-ients of kidney transplant patients to as high as 40 percent among recipientsof liver transplants.12

The most commonly reported source of Cryptococcus in urban environmentsis dust and debris associated with pigeon droppings. There are also numer-ous reports from Australia that the source of infections can be attributed tocertain species of Eucalyptus (e.g., river red gum and forest red gum).13

Prior to an incident or outbreak, routine sampling for fungi, identifyingCryptococcus neoformans, is indicated especially in areas where immune-suppressed patients may be compromised the greatest (e.g., operatingrooms). Particular attention should be given to the air handler systems (e.g.,growths occurring beyond the filtration devices) supplying the operatingrooms, minor surgery suites, and invasive diagnostic rooms.

Cryptococcus neoformans occurs in cultures in the form of round, yeastlikecells, surrounded by a large gelatinous capsule that is thought to contributeto its ability to resist phagocytosis and bypass the initial body defenses.Although they measure 5 to 20 microns in diameter when in tissues, the cellsmeasure 2 to 5 microns in culture media.

Other Pathogenic Fungi

Most of the other fungi which have not been mentioned are either nonpatho-genic, rare occurrences of disease in the United States, or rarely infectiousthrough inhalation. For easy reference, potentially opportunistic and rarelypathogenic airborne fungi are identified in Table 6.2 along with other healtheffects of the more common airborne fungi. This information is intended to


BLE

6.2

Hea

lth

Eff

ects

ofth

eM

ore

Com

mon

Air

born

eFu

ngi.14

–16

Fun

gus

All

erge

nic

Hyp

erse

nsi

tivi

ty

Pn

eum

onit

isP

ath

ogen

icP

oten

tial

ly M

ycot

oxin

(s)

Pos

sib

le C

omm

ent(

s)

Acr

emon

ium

Xhu

mid

ifier

feve

rra

rean

tibi

otic

ceph

alos

pori

nsre

quir

ehi

ghm

oist

ure

Alt

emar

iaX

hum

idifi

erfe

ver

rare

Xgr

ows

once

llulo

seA

rihr

iniu

mX

–po

tent

ially

oppo

r.–

–A

sper

gillu

sso

me

xero

phili

csp

ecie

s

A. f

umig

atus

XX

aspe

rgill

iosi

s&

oppo

r.bX

grow

sat

37°C

orhi

gher

A

. flav

usX

Xas

perg

illio

sis

&op

por.b

Xgr

ows

at35

°Cor

high

er

A. n

iger

XX

swim

mer

’sea

rX

–

A. v

ersi

colo

rX

X–

X–

A

. syd

owii

XX

pote

ntia

llyop

por.b

X–

Aur

eoba

sidi

umX

hum

idifi

erfe

ver

and

saun

ata

ker’

slu

ng–

–w

here

moi

stur

eac

cum

ulat

eses

peci

ally

inba

thro

oms

and

kitc

hens

,und

erw

ind

owsi

lls,

liqui

dw

aste

(e.g

.,se

wag

e)B

ipol

aris

X–

XX

–B

otry

tis

Xw

ine

grow

er’s

lung

––

”nob

lero

t”w

ine

grap

es,

dam

ages

plan

tsC

haet

omiu

mX

–ra

reX

dam

psh

eetr

ock

pape

rC

lado

spon

umX

hott

ublu

ng,m

old

yw

allh

yper

sens

itiv

ity

one

rare

spec

ies

(Cla

dosp

oriu

m c

arri

onii)

Xgr

owth

rang

e:0–

32°C

;m

oist

ure:

>0.

85C

urvu

lari

aX

–cra

re–

–E

pico

ccum

X–

seve

rala

ntib

ioti

cslo

wte

mpe

ratu

regr

owth

rang

e:4°

–45°

C;m

oist

ure:

>0.

86d

Fusa

rium

X–

oppo

rtun

isti

cbX

moi

stur

e:>

0.86

d

PathogenicMicrobes 101G

eotr

icum

X–

rare

––

Muc

orX

Xra

re–

moi

stur

e:>

0.90

d

Nig

rosp

ora

X–

rare

––

Pen

icill

ium

moi

stur

e:>

0.78

P.

mam

effe

iX

Xra

reX

–

P. c

hrys

ogen

umX

X–

anti

biot

icpe

nici

llin

–

P. g

rise

oful

vum

XX

–an

tibi

otic

gris

eofu

lvin

_

P. b

revi

com

pact

umX

X–

X–

P.

fellu

tanu

mX

X–

X–

P.

vir

idic

atum

XX

–X

–R

hizo

pus

XX

rare

–m

oist

ure:

>0.

94d

Stac

hybo

trys

––

–X

moi

stur

e:>

0.94

d;g

row

son

cellu

lose

Toru

laX

––

grow

son

cellu

lose

Tric

hode

rma

XX

pote

ntia

llyop

por.b

Xgr

ows

once

llulo

seU

locl

adiu

mX

––

––

Not

e:

–=

eith

erno

trep

orte

d,n

otco

nfirm

ed,o

rno

tkno

wn.

aH

umid

ifier

feve

r,m

altw

orke

r’s

lung

,woo

dtr

imm

er’s

dis

ease

,str

awhy

pers

ensi

tivi

ty,a

ndfa

rmer

’slu

ng.

bO

ppor

tuni

stic

wit

hw

eake

ned

cond

itio

nsan

dim

mun

e-su

ppre

ssed

ind

ivid

uals

.c

Alle

rgic

fung

alsi

nusi

tis.

dG

row

sat

37°C

orhi

gher

.


provide a quick, easy reference, not to burden the reader with scare tactics.Should the occasion arise that a common mold is suspect of causing disease,additional research is recommended.

Sampling and Analytical Methodologies17, 18

Although many are drought resistant, most pathogenic fungi do not retaintheir viability during air sampling or may be overgrown on the nutrientmedia by other fungi, masking the presence of the slower growing patho-gens. However, where air sampling has been performed for allergenic viablefungi, a pathogen may inadvertently become identified. The methodolo-gies for air sampling for allergenic molds are detailed in Chapter 5, “ViableAllergenic Microbes.” The most commonly identified pathogenic fungi foundduring routine viable allergenic mold sampling is Aspergillus.

Aspergillus fumigatus is thermotolerant and will grow at temperatures of45°C, or higher, which is an extreme temperature for most allergenic fungi.Culturing a viable allergenic mold sample at this temperature serves as ameans for limiting other fungi from growing and overgrowing the Aspergillus fumigatus. On the other hand, the least likely to be identified during viableallergenic mold sampling are Histoplasma capsulatum, Coccidioides immitis,and Cryptococcus neoformans.

The method for Histoplasma capsulatum and Coccidioides immitis is specificfor these pathogens only. Sampling involves the collection of settled dustfrom surfaces and placement in a sterile container. Yet due to the analyticaltime and cost, proactive sampling is rarely performed. Although some spe-cialized mycology labs offer environmental screening for fungal pathogensat a modest cost, in one recent laboratory quote, the minimum analyticalcost was $4000. The reason for the high cost is that analysis involves inject-ing the sample(s) into laboratory rodents, organ extraction, and culturingthe isolated organism, and the laboratories require at least 10 samples behandled in like fashion. This is included in the minimum charge. Anotherlimitation to this process is time. The laboratory turnaround is at least twomonths. Given all the methodology limitations to identifying Histoplasma capsulatum and Coccidioides immitis in occupied spaces, sampling is gener-ally performed only where disease is already known. Where the extent andimpact of the associated disease is increasing, and corrective actions havebeen initiated, the investigator may take a set of samples prior to correc-tive controls and another set after remediation in order to confirm adequatemeasures have been taken. Once again, the time delay is unavoidable, andby the time the results are known, the building will most likely have longsince been reoccupied.

Cryptococcus neoformans also requires a dust sample and is difficult toidentify. As with Histoplasma capsulatum, sampling involves the collection ofsettled dust from surfaces and placement in a sterile container. After samplecollection, the method varies. Only one sample is required. It is serial diluted,


plated on special nutrient agar at the laboratory, and cultured at 37°C. Onceidentified, species and sometimes variety (e.g., Cryptococcus neoformans, vari-ety neoformans and variety gattii) determinations require additional plating(e.g., slant specialized nutrient agar in test tubes). This requires a trainedlaboratory technician and may involve several steps with additional cultur-ing, plating, replating, and stains. These additional efforts may also be timeconsuming and expensive.


There are no definitive guidelines for interpretation of results. Where a patho-genic fungus is region dependent, baseline levels in symptom free areas inendemic regions may provide a means for dose comparisons. Currently thereare no widely published findings nor recognized research studies that haveidentified baseline levels and suggested response limits.

For immune-suppressed patients, any level of exposure may be potentiallylethal. Thus its confirmed presence in a hospital treatment area or associ-ation with medical implements should constitute reason for concern. Thesource should be found and remedied, and medical implements cleaned.With immune-suppressed patients, there has been no determination as to anacceptable level. Many health/environmental professionals, when assessingsensitive environments, express concern at any level of identification andremediate to zero detection.

Airborne Pathogenic Bacteria19–21

Most airborne bacteria are nonpathogenic. The most numerous bacteria arethe environmental bacteria, whereas indoor bacteria that are associated withhumans are referred to as commensal bacteria. Pathogenic bacteria are notcommon and sometimes difficult to isolate.

Most of the pathogenic bacteria indoors occur when they are aerosolizedfrom soil, water, plants, animals, and people, but outdoor exposures may alsooccur. The latter are generally associated with windblown dust. Airbornepathogenic bacteria usually infect the respiratory tract.

Enormous numbers of moisture droplets are expelled during coughing, andsmaller amounts are expelled through talking. A single sneeze by an infectedperson may generate as many as 10,000 to 100,000 bacteria. On the more positiveside, most bacteria do not survive for long once they have become airborne.

Each of the pathogenic bacteria has its own distinct survival adaptationthat permits it to survive long enough to invade its target host. The bacteriaLegionella is highly resistant to acids. The thicker walled, Gram-positive bac-teria (e.g., diphtheria) are resistant to drying, and pathogenic Bacillus anthracis


forms protective spores. The more prominent airborne pathogenic bacteriafound within the United States, those posing the greatest concerns in theoccupational and indoor air environments, are discussed herein.

Pathogenic Legionella22–23

Diseases caused by the water inhabiting bacterial genus Legionella are esti-mated by the Centers for Disease Control at between 25,000 and 100,000 peryear in the United States alone. Collectively, these diseases are referred to as“legionellosis” (e.g., Legionnaires’ disease and Pontiac fever).

There are 34 known species of Legionella and 50 known serogroups.Although many of the species have not been implicated in human disease,Legionella pneumophila, Serogroup 1, is the most deadly, most frequentlyimplicated form associated with Legionnaires’ disease. The latter Serogroup1 and many of the others are frequently found in all environments and waterreservoirs. Their presence alone is not sufficient to constitute a threat.

Virulence is related to the following:

• Species and serogroup• Total amount of viable bacteria in a water reservoir• Aerosolization of contaminated water• Distribution of aerosolized droplets to human hosts• Cooling towers and evaporative condensers—least potential• Water heaters and holding tanks• Pipes containing stagnant water• Faucet aerators• Shower heads• Whirlpool baths• Humidifiers and foggers—highest potential• Reduced host defenses

Other sources of Legionella have been identified in unique environments.In one case, an outbreak was tracked back to the misting of produce in aLouisiana grocery store.24 Another involved a five patient outbreak that waslinked to the aerosol from a decorative fountain associated with a privatewater supply in a hotel in Orlando, Florida.25

Warm water reservoirs provide the greatest potential for amplification ofthe viable organisms. Viable organisms have also been isolated from stag-nant pools, lakes, and puddles of water.26 An example of a highly virulent sit-uation is the presence of Legionella pneumophila in large amount, aerosolizedand distributed from a warm humidifier into the living environment of animmune-suppressed elderly patient.


Although Legionnaires’ disease is primarily a disease of the elderly, it mayimpact younger patients whose health has been compromised and immune-suppressed patients (e.g., AIDS patients). In a healthy adult of working age,infections are usually asymptomatic and may in some cases result in mildsymptoms of headache and fever. In the elderly, prior to the onset of pneu-monia, intestinal disorders are common, followed by high fever, chills, andmuscle aches. These symptoms progress to a dry cough and chest/abdomi-nal pains. Where death occurs, it is typically due to respiratory failure. Deathoccurs to only 15 percent of the less than 5 percent of the exposed individualsshowing disease that develops within three to nine days of exposure.

Pontiac fever is not quite so virulent. Within two to three days of exposure,approximately 95 percent of all exposed individuals develop short-term flu-like symptoms.

The Legionella bacterium is a thin, Gram-negative rod with complex nutri-tional requirements. A unique characteristic that is used in isolating thegenus is its ability to survive at pH 2.

Sampling and Analytical Methodologies for Legionella

Legionella pneumophila is fragile. Once aerosolized and dehydrated it loses itsviability. For this reason, air sampling is unreliable and not recommended.Microbe damage and loss of viability may result in diminished counts.

Water sample collection procedures have been developed. They are con-sidered more reliable and a means for interpreting the results has beendeveloped. Whenever possible, 1 liter of water should be collected in a sterilecontainer. Screw-capped, plastic bottles are preferred collection containers.If the water source has recently been treated with chlorine, neutralize thesample(s) with 0.5 milliliters of 0.1 N sodium thiosulfate. Several samplesshould be taken from suspect/potential reservoirs.27

Sometimes 1 liter of water cannot be collected. Collect as much as is fea-sible and place it in an appropriately sized container. A 1-milliliter samplemay evaporate from or become irretrievable from a 1-liter container. Wherea sample is taken from a faucet or showerhead reservoir, available water isminimal. In such instances, the reservoir should be swabbed with sterileswabs (e.g., polyester medical swabs with a wood stick), contained within asterile enclosure. Upon sampling, each sample swab should be submerged ina small amount of water from the source outlet (e.g., shower, faucet, etc.).

Upon completion of sample collection, all samples should then be sent byovernight freight to a laboratory for analysis. If this is not possible, the sam-ples should be refrigerated until they can be processed. Otherwise, avoidtemperature extremes both in storage and shipping.

At an experienced laboratory, the known aliquots of collected water samplewill be plated onto nutrient medium and cultured for up to three weeks. Thenutrient medium of choice is enhanced, buffered-charcoal yeast extract agar.Prior to the plating, many of the samples are acid-treated for 15 to 30 minutes


then neutralized. Most of the other non-Legionella microbes are destroyed,and the Legionella, having retained its viability, grows unrestricted.

The plates are incubated at 35°C and examined daily for 10 days. Legionellabacteria are slow growing organisms, and colonies that develop early are notlikely to be Legionella bacteria. Sometimes, where there are excessive growths,a determination may be made within a few days. Otherwise, the growth maynot appear for three weeks. Results are reported in terms of organisms permilliliter of water.


Researchers have developed exposure action levels for contaminated water.These levels are based upon extensive experience and field studies. Theydetermined the levels of organisms present in various water sources whereLegionnaires’ disease was known and where it was not a reported prob-lem. The data was compiled and numbers compared. It is from these studiesthat the action levels were created in order to anticipate and avoid costlyoutbreaks. These suggested limits are provided within Table 6.3. They areintended to be used as guidelines only.

The action levels are 1 through 5. Action Level 5 requires the greatestamount of care (e.g., immediate cleaning or biocide treatment). Each sug-gested action includes the preceding actions as well. The minimum recom-mendation for Action Level 1 is the review of routine maintenance programsas recommended by equipment manufacturers. Action Level 2 is a follow-upreview for evidence of Legionella amplification. Action Level 3 representslow contamination, yet elevated levels of concern. A review of the premisesfor direct and indirect bioaerosol contact with occupants and their healthrisk status is recommended. Where outbreaks may become possible, ActionLevel 4 suggests cleaning or biocide treatment of the equipment. For sug-gested remedial actions details, see Table 6.4.

TABLE 6.3

Suggested Remediation Action Criteria Levels for Legionella

Legionella Organisms per Milliliter

Action Levels

CT/EC Potable Water Humidifier/Fogger

<1 1 2 3to 9 2 3 4to 99 3 4 5to 999 4 5 5>1000 5 5 5

Note: CT/EC = Cooling towers and evaporative condensers.Source: From Morris, G., et.al., Legionella Bacteria in Environmental Samples: Hazard

Analysis and Suggested Remedial Actions (Technical Bulletin 1.5), PathConLaboratories, Norcross, Georgia (1998). With permission.


Helpful Hints

Legionella may be hidden and amplified within the cells of other microorgan-isms (e.g., protozoa). Thus a negative result does not necessarily indicate theenvironmental source of a sample is free of Legionella. In such cases, the envi-ronmental professional should comment that low levels are an indication of“low risk.” There are no absolutes.

The occurrence of a potential misdiagnosis of disguised, elevated levelshas led to a choice not to sample by some environmental professionals.However, this choice may potentially result in not identifying those thatare elevated.

TABLE 6.4

Suggested Remedial Response Actions23

Action Level Suggested Remedial Response

1 Review routine maintenance program recommended bythe manufacturer of the equipment to ensure that therecommended program is being followed. The presenceof barely detectable numbers of Legionella represents alow level of concern.

2 Implement Action 1 and conduct a follow up analysisafter a few weeks for evidence of further amplification.This level of Legionella represents little concern, but thenumber of organisms detected indicates that the systemis a potential amplifier for Legionella.

3 Implement Action 2 and conduct a review of premises fordirect and indirect bioaerosol contact with occupants andhealth risk status of people who may come in contact withthe bioaerosols. Depending on the results of the premisesreview, action related to cleaning or biocide treatment ofthe equipment may be indicated. This level of Legionellarepresents a low but increased level of concern.

4 Implement Action 3. Then, cleaning or biocide treatment ofthe equipment is indicated. This level of Legionellarepresents a moderately high level of concern, since it isapproaching levels that may cause outbreaks. It isuncommon for samples to contain numbers of Legionella atthis level.

5 Immediate cleaning or biocide treatment of theequipment is clearly indicated. Conduct post-treatmentanalysis to ensure effectiveness of the corrective action.The level of Legionella represents a high level of concern,since it poses the potential for causing an outbreak. It isuncommon for samples to contain numbers of Legionellaat this level.

Source: From Morris, G., et. al., Legionella Bacteria in Environmental Samples: Hazard Analysis and Suggested Remedial Actions (Technical Bulletin 1.5), PathCon Laboratories, Norcross, Georgia(1998). With permission.


In a 1991 incident involving a Social Security Office Building in Richmond,California, two people died of Legionnaires’ disease. The outbreak involved10 cases and created considerable negative publicity. On March 13, 1995, theU.S. Department of Justice settled the case rather than go to trial. The amountof the settlement was not disclosed, though it was apparently substantial. Akey question in the case was, “Does the policy of not testing, the waiting forcases of Legionnaires’ disease to occur, provide a reasonable standard of care?”28

Another incident involving exposures in a Jacuzzi on a cruise shipoccurred in 1994. A more recent event involved misting of grocery produceand a link to Legionnaires’ disease. Each of these incidents may have beenavoided had prior sampling been performed, elevated levels identified, andthe sources remediated.

The criteria levels described above were developed by a laboratory thatmaintained a stringent quality assurance program, including in-house pro-ficiency testing of the laboratory personnel to insure accuracy and repro-ducibility. The interpretative value of these data may not be applicable withquantitative values from other laboratories that do not have similar qualitystandards.

Other Pathogenic Bacteria

This section excludes Legionella pneumophila. These other “airborne patho-genic bacteria” of potential concern to the environmental professional arenot as well-studied yet still deserve attention.

Disease and Occurrence of Prominent Airborne Pathogenic Bacteria

As they may not be identified during air or diagnostic sampling, disease orthe chance presence of pathogenic bacteria in a routine bioaerosol air samplemay be the only means for suspecting its presence in a given environment.In alphabetical order, typical disease and occurrence of airborne pathogenicbacteria frequently posing a concern are herein discussed.

Bacillus anthracis29, 30

The genus Bacillus includes spore-forming, rod-shaped bacteria that requireoxygen to grow. Although there are numerous species, only Bacillus anthracisis known to be lethal to man. Many species have a commercial use in insectcontrol in the agriculture and forest industry. Although Bacillus anthracis isthe only deadly Bacillus, other forms may be opportunistic. Some species ofBacillus and several species of Clostridium share the commonality of beingthe only pathogenic, spore-forming bacteria. However, Bacillus anthracis maycause disease through airborne transmission.

Mostly a disease of lower animals, Bacillus anthracis is transmissible toman via the skin, alimentary tract, and respiratory tract. Disease in manis typically an occupational disease associated with butchers, shepherds,


herdsmen, and handlers of hides, hair, and fleece. During World War I,anthrax-contaminated articles (e.g., shaving brushes) from Asia and SouthAmerica provided a source for infection. Currently, reports of anthrax dis-ease come from Haiti and Zimbabwai.31 The primary concern is for airborneexposures that result in pulmonary anthrax.

Pulmonary anthrax is due to inhalation of the microorganisms from theair. Although uncommon, it is the most dangerous. It occurs occupationallyamong those who handle/sort wool and fleece where the spores are floatingin the air from the infected material. It is characterized by symptoms of pneu-monia that frequently becomes fatal septicemia. The dose-response is low.Research indicates that only a few inhaled spores are required to produce dis-ease. Immunization is possible, and infections are treated with antibiotics.

During World War II, Bacillus anthracis was researched heavily due to its air-borne pathogenicity and resistance of the spores to drying. An effort was madeto develop drug-resistant strains, but it is not clear as to their success. They did,however, find that the spores can remain viable in soil for as long as 60 years.

Bacillus anthracis is also a hazard to textile workers working with importedanimal hair. The primary concern may be airborne exposures, but the mostlikely source of infection is through the skin.

The genus Bacillus is characterized by Gram-positive rods measuring 4.5 to10 microns in length by 1 to 1.25 microns wide. They grow well on all com-mon nutrient media, most rapidly between the temperatures of 41°C and43°C in aerobic conditions. Spores can be destroyed by any of the followingmethods:

• Boil for 10 minutes.• Heat at 140°C for three hours under dry conditions.• Disinfect with 3 percent hydrogen peroxide for one hour or with

4 percent potassium permanganate for 15 minutes.

Corynebacterium diphtheriae32

Only one species of Corynebacterium is an airborne pathogen. That isCorynebacterium diphtheriae, the cause of diphtheria.

Diphtheria results from airborne exposures to the bacterium. Corynebacterium diphtheriae enters the body via the respiratory route, lodging in thethroat and tonsils. Death may result from suffocation by blockage of the airpassages and by tissue destruction from the toxin involved.

Occasionally, it has affected the larynx, resulting in membranous croup, orthe nasal passages, causing membranous rhinitis. Diphtheria infections ofthe conjunctiva and of the middle ear are less common, and cutaneous orwound diphtheria is only occasionally observed. However, wound diph-theria may be serious, resulting in a systemic infection. Systemic infectionscan severely affect the kidneys, heart, and nerves. Primary infection ofthe lungs and diphtheritic meningitis has been observed on rare occasion.


Thus most of the concerns for the diphtheria bacillus would be in hospitalenvironments.

Corynebacterium diphtheriae are generally described as Gram-positive rodswith irregular staining responses. The ends of each rod are swollen andrespond greatest to staining, a characteristic unique to the genus. The bacte-ria measure 1 to 6 microns in length and 0.3 to 0.8 microns in width.

Mycobacterium tuberculosis33,34

Mycobacterium tuberculosis has three varieties (e.g., hominis, bovis, and avian).The Mycobacterium tuberculosis variety hominis is highly infectious via air-borne transmission of the disease. Not only are there different varieties, butthere are different strains.

Resistance to drug treatment occurs in vitro and in vivo. In the infectiousstage, drug resistance is more common with the Mycobacterium tuberculosisthan other pathogenic bacteria because of the extended, lengthy antibiotictreatments required to fight the disease. Their persistence allows greaterchances for mutated strains to develop.

Tuberculosis is one of the most important communicable diseases in theworld, affecting more than 50 million people. In the United States, more than50,000 new cases are reported annually, and 10,000 resultant deaths occurper year. However, disease does not always develop in all those who havebeen exposed. There is a possible dose–response relationship.

Potential transmission occurs in public places and hospitals, typically byairborne droplets of contaminated sputum. Other modes of infection (e.g.,genitourinary tract, conjunctiva of the eyes, skin, and alimentary tract) areless common.

Bacteria-laden droplets and dust particles are inhaled, settle in the lungs,and grow. In an individual with low resistance, an infection occurs. Extensivedestruction and ulceration of the lung tissue progresses to other parts of thebody, predominately the spleen, liver, and kidneys. If not controlled by anti-biotics, death may result.

The tuberculosis bacteria are “acid-fast” rods, measuring 2 to 4 microns inlength 0.3 to 1.5 microns wide. Specialized enriched media and aerobic con-ditions are required for growth and isolation of the bacillus. The optimumtemperature for growth of the mammalian varieties is 37°C with a range of30°C to 42°C.

Various Genera of Pseudomonas35, 36

Pseudomonas includes more than 30 species that are found in water, soil, andcompost. Of the many species, there are only a few pathogenic types.

The most widely known pathogenic form is Pseudomonas aeruginosa (alsoreferred to as Pseudomonas pyocyanea). They grow readily on all ordinary cul-ture mediums and most rapidly between the temperatures of 30°C and 37°C.


Although they typically require oxygen, some will grow in anaerobic condi-tions. As they produce a bright blue-green color that diffuses into its substrate,a blue-green color has, at times, been observed on substrates (e.g., surgicaldressings) where the bacteria grew.

Pseudomonas aeruginosa frequently occurs as a secondary invader of infectedtissues or tissues which have been traumatized by operation. Children andimmune-suppressed patients are particularly susceptible to infection. Often-times,infectionsareassociatedwiththeurinaryandrespiratorytracts.Abscessesmay develop in different parts of the body, especially the middle ear. Althoughrare, it may also cause endocarditis, pneumonia, meningitis, and systemicpyocyanic infection. The latter generally occurs in patients with severe burnwounds where the bacterium enters and spreads throughout the body, causingendotoxic shock and focal necrosis of the skin and internal organs. As they donot respond well to antibiotics, systemic infections are almost always fatal. Forthis reason, the primary area of concern for this bacterium is in hospitals.

It should be noted that bacteriostatic detergents (e.g., cationic detergents)provide a growth environment for certain Gram-negative bacteria; (e.g.,Pseudomonas aeruginosa). Many of these soaps are used in skin antiseptics,mouthwashes, contact lens solutions, and disinfectants for hospitals.

Pseudomonas aeruginosa is also an insect pathogen and has consequently beenconsidered for use as an insecticide. Its limited shelf life and potential to causedisease in humans has been a deterrent from its use as a pest control agent.

Pseudomonas pseudomallei infections may be asymptomatic or result inacute, toxic pneumonia or overwhelming septicemia. The organism hasbeen isolated from moist soil, market fruits, and vegetables, and well andsurface waters in Southeast Asia. Pseudomonas maltophilia is suspect as well.However, over the past few years, the latter suspect has undergone numer-ous name changes and is now referred to as Stenotrophomonas maltophilia. It isno longer classified as genus Pseudomonas.

The Pseudomonas bacteria are Gram-negative rods, measuring 1.5 to 3microns in length by 0.5 microns wide. They grow well on all common nutri-ent media and grow most rapidly between the temperatures of 30°C and37°C in aerobic conditions. Once airborne, the bacterium loses its viabilitywith drying. So exposures must occur shortly after the bacteria have becomedispersed into the air.


If pathogenic bacteria are suspect, the sampling equipment of choice forlow to moderate levels (e.g., less than 10,000/m3) are the culture plate impac-tors (e.g., Andersen impactor). In situations involving potentially highernumbers, liquid impingers are preferred, primarily due to their ability todilute the solution and plate from several diluents. Notwithstanding sur-face samples, filter air sampling is easier but may theoretically be used only


for the spore-forming Bacillus anthracus for which analysis is not availablecommercially. Mycobacterium tuberculosis is also of questionable feasibility.

Although air sampling for Mycobacterium tuberculosis has been attemptedby some environmental professionals, it is not recommended by mostmicrobial laboratories. Where the concern involves this pathogen, alterna-tive surface sampling may provide more reliable results. Otherwise, a nega-tive air sample can’t be considered conclusive as to the nonpresence of thepathogen.

In the laboratory, samples that are not already on a culture medium areplated. Filter surfaces are washed, the suspended material plated on nutrientmedia. Impinger solutions are also plated.

Most pathogenic bacteria will grow on tryptic soy agar or a nutrient bloodagar, the same nutrients used to sample for total bacteria during indoor airquality studies. Although the nutrient media of choice is blood agar, themicrobial laboratory chosen to perform the analysis should be consulted fortheir preferred media.

Incubation should take place at 35°C for most pathogenic bacteria.Pathogenic bacteria tend to grow best at elevated temperatures, and thehigher temperatures restrict growth of most environmental bacteria thatcould overrun a sample.

With a few exceptions, colonies may be counted within one to two days.One such exception is Mycobacterium tuberculosis that require up to two weeksfor colonies to become visible.

Where shipping is necessary, a count may take place upon receipt of awell-insulated shipment of culture plates. Impinger samples should beplated prior to shipping to avoid growth within the collection solution dur-ing transportation.


Experience and careful consideration of comparative or diagnostic samplesare important for developing sound conclusions. The sampling methodolo-gies alone may damage some of the otherwise viable, unprotected bacteria.Thus the mere identification of specific microbes in an indoor environment,particularly in hospitals, may be cause for remediation.

The outdoor environmental contribution of a pathogenic bacterium mayalso be important in evaluating the findings and devising a remediationplan. Where the levels are as high or higher outdoors, indoor exposure con-trols may be more difficult or, in some cases, not required.

Where air sampling is performed for Mycobacterium tuberculosis, positivefindings of any level should be acted upon. However, negative results maynot have any meaning. Negative findings should not be relied upon wherefalse negatives, particularly involving drug-resistant strains, can lead to alethal, false sense of security.


Pathogenic Protozoa37, 38

Typically larger than the bacteria and mold spores, protozoa are unicellularmicroorganisms that are free-living and thrive in water. They may be locatedin damp soil, mud, drainage ditches, puddles, ponds, rivers, and oceans.Those that represent an occupational and environmental concern are theamoebae, measuring in size from 8 to 20 microns in diameter.

Amoeba move by flowing pseudopodia, or false feet, and usually live in freshwater. They are naked, or unprotected, during vegetation. Otherwise, theysecrete a protective shell. They may be found in home humidifiers where theyhave been known to cause an allergic reaction called humidifier fever. The gen-era Naegleria and Acanthanoeba have been implicated in building-related illness,yet most amoeba-related disease is associated with waste treatment plants.

In the absence of water, the Naegleria can encyst to protect itself. These spher-ical cysts are 9 to 12 millimeters in diameter. The seriously parasitic amoebae,which are not typically found in fresh water, are not generally a concern.

Sampling and Analytical Methodology

Sampling equipment may be the Litton sampler, two in-series all-glassimpingers, or sieve plate impactors. High volume air samples should be col-lected close to the probable aerosolization source, avoiding other potentialcontaminant sources (e.g., not immediately under running water). Equipmentshould also be sterilized.

The Litton sampling tube should be cleaned, using 70 percent ethanol andsubmerged in two separate distilled water rinses for 30 to 60 minutes each.The last rinse should be collected and analyzed for background amoeba con-tamination of the tubing.

The all-glass impingers should be cleaned, and the final rinse watershould be analyzed for background contamination. The final in-series sam-ples (consisting of 150 milliliters of water) should be combined and ana-lyzed collectively.

At the laboratory, each sample solution should be plated in five differentamounts onto nutrient agar plates with the common bacteria Escherichia coliand incubated between 43°C and 45°C. Pathogenic amoebae will grow morerapidly than nonpathogenic types in these conditions.

The amounts of solution per sample to be plated should be 0.01, 0.1, 1, 10,and 100 milliliters. They are treated differently. The 10-milliliter sampleshould be centrifuged at 500× gravity for 15 minutes, and the product plated.The 100-milliliter sample should be filtered through a 1.2 micron pore sizedcellulose filter that must be quartered or halved and inverted in an agar plate.The smaller aliquots should be plated directly onto separate plates. Assureall plates have been properly labeled.


Incubation may take up to seven days at 45°C (or at 35°C for some of theless heat tolerant species), and then a series of more complex manipulationtechniques are performed. The resultant suspension requires an additionalthree hours of time-lapsed examinations for concentration determination ofthermophilic Naegleria species. Speciation requires an additional two weeksin vivo mouse pathogen studies.


Disease, coupled with reservoir source identification, is diagnostic and doesnot require quantitation. The existence of these heat-loving amoebae in areservoir requires immediate remediation with an oxidizing biocide (e.g.,sodium hypochlorite or hydrogen peroxide).

Viruses39

Viruses, the smallest living organisms, are obligate intracellular parasites.They are subdivided into animal, plant, and bacterial parasites. The size ofanimal viruses ranges from 20 to 300 nanometers.

Viruses are host specific and become invasive only when specific hostorgans become accessible. Host entry may be through any of a number ofmechanisms, yet most enter through the respiratory tract.

A line of defense (e.g., nasal hairs and mucous secretions) must be passed.Then, the virus must be transported (e.g., through the blood supply) to itstarget cell preference(s). Once the target cells have been identified, the viruspenetrates the cell wall barrier and takes command of the cell’s replicat-ing mechanism. The virus is reproduced within 6 to 48 hours. A protec-tive structure is built around each replicated virus, and the progeny vironeither destroys the host cell or forms a bud that allows it to pursue otherhost cells.

Animal viruses are usually recognized by the diseases they cause (e.g.,AIDS). The greatest concerns with aerosolized animal viruses are influ-enza, measles, chicken pox, and some colds. Virulence is influenced by thefollowing:

• Specific type of virus• Concentration in an aerosol• Aerosol particle size• Individual susceptibility

Indoor contamination occurs in residences, offices, laboratories, hospitals,and animal confinement areas. Outdoor exposures occur around livestock,


sewage treatment plants, caves, and water sources. Environmental factorsaffecting virus survivability are relative humidity, temperature, wind, ultra-violet radiation, season, and atmospheric pollutants.

Amplification of viruses does not occur without a host. Hence, increasednumbers will not occur in water or organic substrates of air handlers. The airhandlers will merely serve as a means of conveyance. Acids, extreme tem-peratures (e.g., less than −20°F or greater than 150°F), and drying can, how-ever, damage or destroy most viruses. This information is important for anexposure-limiting consideration for prevention and control of viruses andfor handling samples.

Sampling is typically neither recommended nor requested. Because virusesare obligate parasites, they cannot be cultured from environmental sampleson laboratory media. The presence of disease is generally tracked epidemio-logically to the source or sources.

Summary

Pathogenic microbes are rarely encountered in indoor air quality situations,and it is usually the result of an epidemic of cases when they become suspect.Some attempts are made in hospitals at proactive projections and occasionalsampling. Yet the investigator will generally be called in for assistance afteran elevated number of suspect disease cases are associated with a building.The challenge may be more that of confirmation of a suspect agent and locat-ing the source.

References

1. Bailey, M.R., and E.G. Scott. Diagnostic Microbiology, 3rd ed. C.V. MosbyCompany, St. Louis, Missouri (1970).

2. Conant, N.F., et al. Manual of Clinical Mycology, 3rd ed. W.B. Saunders Company,Philadelphia (1958).

3. U.S. Department of Health, Education, and Welfare. Occupational Diseases: A Guide to Their Recognition. U.S. Government Printing Office, Washington, DC,revised edition (June 1977).

4. Rhame, F.S. Endemic Nosocomial Filamentous Fungal Disease: A ProposedStructure for Conceptualizing and Studying the Environmental Hazard. Infection Control. 7(2):126 (1986).

5. Krasinski, K., et al. Nosocomial Fungal Infection during Hospital Renovation.Infection Control. 6(7):278–82 (1985).


6. Weems, J.J., et al. Construction Activity: An Independent Risk Factor for InvasiveAspergillosis and Zygomycosis in Patients with Hematologic Malignancy.Infection Control. 8(2):71–5 (1987).

7. Cross, A.S. Nosocomial Aspergillosis: An Increasing Problem. Journal of Nosocomial Infection. 4(2):6–9 (1985).

8. Mascola, J.R., and L.S. Rickman. Infectious Causes of Carpal Tunnel Syndrome:Case Report and Review. Reviews of Infectious Diseases. 13(5):911–7 (1991).

9. Kilburn, C.D., and D.S. McKinsey. Recurrent Massive Pleural Effusion dueto Pleural, Pericardial, and Epicardial Fibrosis in Histoplasmosis. Chest.100(6):1715–7 (1991).

10. Centers for Disease Control. Update on Coccidioidomycosis in California.Morbidity and Mortality Weekly Report. 43(23):421–3 (1994).

11. Chen, G.H., et al. Case Records of the Massachusetts General Hospital—WeeklyClinicopathological Exerciser. New England Journal of Medicine. 330(7):490–6 (1994).

12. Paya, C.V. Fungal Infections in Solid-Organ Transplantation. Clinical Infectious Diseases. 16(5):677–88 (1993).

13. Pfeiffer, T.J., and D.H. Ellis. Environmental Isolation of Cryptococcus Neofor-mans Var. Gattii from Eucalyptus Tereticornis. Journal of Medical and Veterinary Mycology. 30(5):407–8 (1992).

14. Gallup, J., and M. Velesco. Characteristics of Some Commonly Encountered Fungal Genera. Environmental Microbiology Laboratory Inc., Daly City, California(1999).

15. Ajello, L., et al. Microbes in the Indoor Environment: A Manual for the Indoor Air Quality Field Investigator. Path Con Laboratories, Norcross, Georgia (1998).

16. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida, p. 259 (1995).17. Morris, G.K., and B.G. Shelton. A Suggested Air Sampling Strategy for Microorganisms

in Office Settings (Technical bulletin). PathCon Laboratories, Norcross, Georgia(1994).

18. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in the Indoor Air Environment—Fungi. ACGIH, Cincinnati, Ohio (1989).

19. Stewart, F.S. Bacteriology and Immunology for Students of Medicine, 9th ed. Williamsand Wilkins Company, Baltimore, Maryland (1968).

20. Morris, G.K., and B.G. Shelton. Legionella in Environmental Samples: Hazard Analysis and Suggested Remedial Actions (Technical Bulletin 1.4). PathConLaboratories, Norcross, Georgia (1995).

21. Brock, T.D., and M.T. Madigan. Biology of Microorganisms, 6th ed. Prentice Hall,Englewood Cliffs, New Jersey (1991), pp. 518–520.

22. Burge, H.A. Bioaerosols—Legionella Ecology. Lewis Publishers, Boca Raton,Florida (1995), pp. 49–76.

23. Morris, G., et.al., Legionella Bacteria in Environmental Samples: Hazard Analysis and Suggested Remedial Actions (Technical Bulletin 1.5), PathCon Laboratories,Norcross, Georgia (1998).

24. New York Times. Legionella from misting in grocery store. 139:A1(N)(Jan. 11, 1990).

25. Hlady, W.G., et al. Outbreak of Legionnaire’s Disease Linked to a DecorativeFountain by Molecular Epidemiology. American Journal of Epidemiology.138(8):555–62 (1993).

26. Alcamo, I.E. Fundamentals of Microbiology, 3rd ed. Benjamin/CummingsPublishing Company, Inc., Redwood City, California. (2004), p. 243.


27. Gorman, G.W., J.M. Barbaree, J.C. Feeley, et al. Procedures for the Recovery of Legionella from the Environment (Bulletin). CDC, Atlanta, Georgia (November1992).

28. Sheldon, B.G. Social Security Building Incident Where Settlement is Alledgedto Have Been Quite Expensive (Oral communication). PathCon Laboratory,Norcross, Georgia (July 1995).

29. Atlas, R.M., and R. Bartha. Microbial Ecology: Fundamentals and Applications.Benjamin/Cummings Publishing Company, Menlo Park, California (1987),p. 476.

30. Burrows, W. Textbook of Microbiology. W.B. Saunders Company, Philadelphia(1968), pp. 614–619.

31. Morris, G.K. Exposures to Bacillus Anthracis (Oral communication). PathConLaboratories, Norcross, Georgia (November 1995).

32. Brock, T.D., and M.T. Madigan. Biology of Microorganisms, 6th ed. Prentice Hall,Englewood Cliffs, New Jersey (1991), pp. 513–514.

33. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in the Indoor Air Environment—Bacteria. ACGIH, Cincinnati, Ohio (1989).

34. Stewart, F.S. Bacteriology and Immunology for Students of Medicine, 9th ed. Williamsand Wilkins Company, Baltimore, Maryland (1968), pp. 357–60.

35. Ibid., pp. 278–28036. Ibid., pp. 282–283.37. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in

the Indoor Air Environment—Protozoa. ACGIH, Cincinnati, Ohio (1989).38. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995),

pp. 122–123.39. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in

the Indoor Air Environment—Viruses. ACGIH, Cincinnati, Ohio (1989).

119

7ToxigenicMicrobes

Toxigenic microbes are those that produce mycotoxins and endotoxins, thetoxins associated with fungi and bacteria, respectively. As toxigenic microbeshave often been overlooked, environmental professionals are becoming moreaware of their potential impact on the indoor air quality.

Organic dust toxic syndrome is thought to be associated with a complexmix of mycotoxins, endotoxins, antigens (allergenic material), and glucans.This is a poorly characterized condition similar to “humidifier fever.” Flu-likesymptoms include fever, chills, muscle aches, malaise, and chest tightness,and illness is short lived, usually less than 24 hours. Exposures and symp-toms are generally associated with high dust levels in composting and someagricultural operations.

Not only do mycotoxin and endotoxin exposures result in adverse healtheffects, but they may have a positive impact as well. Whereas one mold maycause cancer, another may protect against pathogens. Excessive exposuresto endotoxins may result in respiratory distress, shock, and death, but low-level exposures may stimulate the immune system, which may help reducethe risk of cancer.

Each of the above-mentioned toxigenic microbes is worthy of mention andshould not be overlooked when assessing an indoor air environment. Theyare discussed herein.

Mycotoxins1,2

Mycotoxins are toxic by-products of the metabolic process of fungi. Thosethat produce the mycotoxins gain a competitive edge over other micro-organisms for food. Many fungi produce at lease one mycotoxin. Someproduce many different mycotoxins, and others do not produce any. SeeTable 7.1.

Exposures to mycotoxins may occur by eating poisonous/hallucinogenicmushrooms, eating contaminated foods, breathing heavily contaminated air,or handling contaminated materials with unprotected hands. The greatestimpact has been on agriculture and livestock. The feeds become contami-nated with toxin-producing fungi. The livestock eat the heavily contami-nated feeds with a possible outcome of death.


The mycotoxins are primarily concentrated in the cell walls of the fungalspores, but these by-products have also been identified in the fungal myceliumand food substrates. For instance, Aspergillus flavus produces an aflatoxin in thespore wall. This aflatoxin rapidly may diffuse out of the wall and into a waterreservoir. However, mycotoxins are not known to become airborne without acarrier (e.g., mold spores and mycelium) and are not volatile compounds.

Possible short-term symptoms of excessive exposures to mycotoxins includenausea, vomiting, dermatitis, cold and flu symptoms, sore throat, fatigue,

TABLE 7.1

Mycotoxins Associated with Certain Fungi3

Fungus Mycotoxin

Acremonium spp. Cephalosporin (antibiotic)Alternaria alternate and Phoma sorghina Tenuazoic acidAspergillus clavatus Cytochalasin E

PatulinAspergillus flavus and Aflatoxins Aspergillus parasiticusAspergillus fumigatus Fumitremorgens

GliotoxinAspergillus nidulans, Aspergillus versicolor, and Cochliobolus sativus

Sterigmatocystin

Aspergillus ochraceus, Penicillium verrucosum, and Penicillium viridicatum

Ochratoxin A

Cladosporium spp.Cladosporium cladosporioides

Epicladosporic acidCladosporin and emodin

Claviceps purpurea Ergot alkaloidsFusarium graminearum Deoxynivalenol

ZearalenoneFusarium moniliform FumonisinsFusarium pose and Fusarium sporotrichoides T-2 toxinPenicillium chrysogenum Penicillin (antibiotic)Penicillium crustosum Penitrem A

Roquefortine CPenicillium expansum Citrinin,

Patulin,Roquefortine C

Penicillium griseofulvum and Penicillium viridicatum GriseofulvinPithomyces chartarum Sporidesmin

PhylloerythrinStachybotrys chartarum (atra) Satratoxins,

Verrucarins,Roridins,Stachybocins

Tolypocladium inflatum Cyclosporin (antibiotic)

ToxigenicMicrobes 121

and diarrhea. Some other reported effects that are more species depen-dent are eczema, photosensitization, hemolysis, hemorrhage, and impairedor altered immune function that can result in opportunistic infections.Long-term effects are even more species dependent. Specific species maybe hepatotoxic (e.g., Aspergillus flavus), cytotoxic (e.g., Aspergillus fumigatus),teratogenic (e.g., Penicillium viridicatum), tremorgenic (e.g., Penicillium expansum), tumorigenic (e.g., Aspergillus fumigatus), nephrotoxic (e.g., Aspergillus clavatus), mutagenic (Aspergillus parasiticus), or carcinogenic (e.g., Aspergillus flavus, Cochiobolus sativus).4

Some mycotoxins are beneficial to man in the form of antibiotics (e.g.,Penicillium chrysogenum). Antibiotics are toxic to pathogenic bacteria. As such,the antibiotic mycotoxins revolutionized the world and saved many lives.

There is a dose-response relationship for mycotoxins similar to that of chem-ical toxins. The impact of mycotoxins is based upon the type of toxin, the ani-mal species impacted, the route of entry, and susceptibility of the individual.5

Disease and Occurrence

Throughout history, mycotoxins have played a significant role in the health ofman and animal. Toxicity and dramatic exposures have typically been asso-ciated with ingestion of contaminated foods. Ergotism, also known as SaintAnthony’s Fire, was documented as early as 430 B.C. by the Spartans. It wascaused by ingestion of rye that was contaminated with alkaloid-containingfungi. Symptoms were gangrene, convulsions, and death.

In 1960, feed (i.e., Brazilian peanut meal) that was contaminated withAspergillus flavus killed 100,000 turkeys in the United Kingdom. The toxinsthat were identified came to be named “aflatoxins.”

Aspergillus flavus and Aspergillus parasiticus create aflatoxins that are car-cinogenic and may cause some short-term health effects that have yet to beclarified by medical researchers. These molds grow predominately in warm,humid environments and are typically associated with peanuts, grains, sweetpotatoes, corn, peas, and rice. Aflatoxins have been reported to cause livercarcinomas in animals and are believed to be among the most potent of car-cinogens in man.6 They are primarily associated with liver cancer, and therehave been some concerns raised regarding inhalation and lung cancer.

There is one report of two deaths due to pulmonary adenomatosis that arethought to be related to airborne aflatoxin exposures. Although autopsiesindicated the presence of aflatoxin in both patients’ lungs, the findings werenot conclusive.7 The verdict regarding airborne aflatoxins is still out.

Trichothecene toxins are cytotoxins produced by some species of Fusarium,Acremonium, Trichoderma, Myrothecium, and Stachybotrys. Reported symptomsinclude headaches, sore throats, hair loss, flu-like illness, diarrhea, fatigue,dermatitis, and generalized malaise.

The year 2000 saw the birth of a new cottage industry—the quest for andremediation of “toxigenic molds.” Based on a multimillion-dollar law suit,


Stachybotrys chartarum was tagged by the news media as the “death mold.”Investigators began targeting Stachybotrys chartarum with fervent interestin an effort to stem the tide of panic. Some “experts” began targeting thegenus Penicillium as well. Indoor environments with water damaged build-ing materials and potentially toxigenic fungi were posted with “biohazard”signs and remediated at great expense to the building owner or insurancecompany. Most, if not all, of the investigations mentioned above involvingexpensive remediation have yet to confirm the presence of mycotoxins. So,as of the publication of this book, the saga continues.

Many species of Penicillium produce mycotoxins. Some species (e.g.,Penicillium viridicatum) produce mycotoxins that are potentially tumorigenic,teratogenic, and hepatotoxic.4 Others produce antibiotics, including penicil-lin (e.g., Penicillium chrysogenum).

To complicate matters, toxins are not always produced. The nutrient (orsubstrate) upon which the mold grows impacts its metabolites. Indoor envi-ronments and laboratory nutrients may result in a variation from the norm.Thus the presence of amplified numbers of mycotoxin-producing fungi in abuilding does not necessarily follow that it is producing the toxin. Likewise,the failure of a mold to produce toxins in laboratory conditions does notnecessarily mean that it does not produce the toxin under natural environ-mental conditions.

Other factors that may affect production of mycotoxins are competitionfrom other microbes, pH, temperature, and water. For instance, aflatoxinproduction is associated with drought and heat stress.

A recent research publication indicated:

In many cases, the presence of fungi thought to produce the mycotoxinswas not correlated with the presence of the expected compounds. However,when mycotoxins were found, some toxigenic fungi usually were present,even if the species originally responsible for producing the mycotoxin wasnot isolated. We concluded that the identification and enumeration of fun-gal species present in bulk materials are important to verify the severityof mold damage but that chemical analyses are necessary if the goal is toestablish the presence of mycotoxins in moldy materials.8

In other words, the presence of a toxin-producing mold does not always atoxin make. Nevertheless, given the cost and time required for toxin analy-sis, as well as potential difficulties in detecting low levels of these chemi-cal agents in environmental samples, assessment for mycotoxin-producingfungi is still regarded as the most practical means of assessing potentialtoxin exposures in indoor environments.

In summary, most cases of mycotoxin poisoning occur in rural and agri-cultural settings as a result of ingestion or skin contact. There have beenminimal studies and research into the possible relationship between air-borne mycotoxins and its impact on humans.


Sampling and Analytical Methodologies2

There are two different approaches to sampling for mycotoxins. The fungimay be identified with an emphasis on fungi identification for those moldsthat may potentially create toxic by-products, or the investigator may focuson toxin identification. The latter, although preferred, is neither easy nortechnically feasible for commercial laboratories.

Fungi Identification

Species identification is a must and can only be determined through viableair sampling. Yet where the fungi are to be identified from culturing, manyof the toxin-producing fungi may not compete well with the other fungi,or they may no longer be viable while the toxins still persist in nonviablespores. Special nutrient media may be necessary depending on the investiga-tors emphasis (e.g., Stachybotrys), and the laboratory and its preferences (e.g.,special cellulose agar) See Figure 7.1.

Mycotoxins have the same effect—alive or dead—and the effect of tox-ins is based on a dose-response relationship. For this reason, total viable/nonviable air sampling is as important as viable air sampling. Both typesof sampling should be performed in tandem. The methods are described inChapters 5 and 7.

(a)

FIGURE 7.1Photomicrographs of Toxigenic Molds: (a) Stachybotrys, (b) Fusarium, and (c) Aspergillus flavus[Courtesy of Sean Abbott, PhD, Natural Sink Mold Lab, Reno, Nevada].


Toxin Identification

Sampling methodologies for mycotoxins have recently been developed andhave become available commercially. Methods include air, contaminated-surface wipes, surface dust, and bulk sampling.

Air sampling requires a sufficient amount of air volume to enable cap-ture of greater than 100,000 spores per sample. Based on an airborne mold

(b)

(c)

FIGURE 7.1(Continued)


spore exposure of 100 counts/m3, the latter 100,000 spores sample wouldrequire an air volume of not less than 106 liters, or 46 days of continuoussample at 15 liters per minute. If the airborne mold spore exposure were1000 counts/m3 (an unlikely indoor airborne mold spore count), the sampleduration required would be about 5 days. Prior to taking mycotoxin air sam-ples, airborne mold spore levels should be determined using one of viable/nonviable sampling methodologies in Chapter 5. With known airborne sporecounts, the investigator can calculate minimum air volume required to col-lect 100,000 spores. Report sample number (or location) and air volume to thelaboratory.

Contaminated-surface wipe sampling may only be performed on areaswhere molds have been identified and surfaces are heavily contaminated.A dusty surface is not sufficient and requires a different sample technique.Sample supplies should include sterile methanol wipes or swabs. Some labo-ratories supply field kits that consist of enclosed cotton swabs with methanolas well as templates to delineate the area(s) sampled. Lightly contaminatedsurfaces may require larger surface area sampling than heavily contami-nated surfaces, and the size of the area template or number of areas sampledfor one analytical run should be adjusted accordingly. Report sample num-ber (or location) and surface area sampled to the laboratory.

Surface dust samples require the collection of a minimum of one tea-spoon of dust. For general dust sampling methods, see the “Surface DustCollection” section in Chapter 15. The surface dust sampling methods formycotoxins should be performed with supplies that have been cleaned (e.g.,wash scraping items and collection attachments with soapy water, rinse,and thoroughly dry). A minimum area of 1 square foot should be sampled.Report sample number (or location) and surface area sampled to the labora-tory. Bulk samples may be taken of carpeting, insulation, gypsum board,wood flooring, sheet vinyl wallpaper, and other materials that have visibleevidence of mold growing on the surface(s). The size of the material selectedto sample should be a least 1 inch square for heavy contamination and asmuch as 1 square foot for light contamination. Using clean tools, cut thematerial out, place it in a ziplock baggie, and label the bag with the samplenumber or location.

All samples should be labeled at the time each sample is taken, and theinvestigator must report to the laboratory sample number (or location) andair volume or surface area sampled. A log of sample number(s) should bemaintained by the investigator with a detailed description of the samplesites (e.g., exact location where the sample was taken, type of material, andappearance of the sample), environmental conditions, and other informationthat may be applicable regarding the sample. All samples with required lab-oratory data and chain of custody should be shipped in a chilled container(e.g., Styrofoam cooler with a cool pack).

Analysis involves dust extraction and high-pressure liquid chromato-graphy or thin-layer chromatography. See Table 7.2 for a sample of laboratory


quantification results of mycotoxins produced by some cultivated fungalspecies.

In response to food testing required by the U.S. Food and DrugAdministration (FDA), owners of granaries and corn storage facilities rou-tinely perform a quick test for the presence of aflatoxin. Although the FDAprobes larger samples and has analyses performed by a commercial labora-tory, colorimetric test kits (based on immunoassay tagging of the mycotoxin)are available commercially and are readily used for screening by the storagefacilities.9 This approach has yet to be introduced into or used by environ-mental professionals to screen air and surface samples.

Another technique that may hold some promise for environmental pro-fessionals is the ELISA detection kits. They are currently used to screen formycotoxins in grains, nuts, and spices. The kits are commercially availableand can be performed by the investigator within two hours. They are quali-tative and quantitative in separate kits for the following:

• Aflatoxin• Fumonisin• Ochratoxin• T-2 Toxin• Vomitoxin• Zearalenone


There are no definitive guidelines for interpretation of results. First, the fungiable to produce toxins may not produce these mycotoxins under the condi-tions that the contaminant is being assessed. Second, if the toxins could beidentified, there are no known comparative values by which to determinethat a problem does indeed exist.

On the other hand, a thorough assessment of dust for the presence of myc-otoxins in a given environment may permit an investigator to determine ifthe suspect mycotoxins are present or not. The type of toxin sought should

TABLE 7.2

Quantified Mycotoxins Produced by Cultivated Fungal Species10

Mold Toxin Spores (ng/g)

Aspergillus fumigatus Fumigaclavin C 930,000Aspergillus niger Aurasperone 460,000Aspergillus parasiticus Aflatoxin B1 16,600Penicillium oxalicum Secalonic acid D 1,890Aspergillus parasiticus Norsolorinic acid 280


be based on fungal species found. Finding that the suspect mycotoxins arepresent could be important information in itself, or outdoor samples may becompared to indoor samples.

Also, telltale symptoms may be used in conjunction with the presence offungi known to potentially cause the same symptoms. Although this tech-nique has been used more than the mycotoxin identification method, thesymptoms must be properly diagnosed and some symptoms may be causedby other environmental exposures. In the latter case, a source misdiagno-sis could result in misdirected efforts to remediate. If fungi (e.g., Penicillium)is remediated and the problem is associated with a toxic chemical (e.g.,Chlordane), the true cause of the symptoms remain unidentified.

The environmental professional is on his or her own or must rely on guid-ance from one with experience in this area of expertise. The laboratory cho-sen to perform the work should be able to either provide guidance or directyou to someone competent in that area. Each case is unique and depends onseveral variables including intent and sampling strategy. All factors must beconsidered in the final interpretation.

Bacterial Endotoxins11–13

Endotoxins are toxic components of the lipopolysaccharide, cellular mem-brane of Gram-negative bacteria. Although the bacteria may be renderednonviable, the endotoxin retains its toxicity, even through extremely hightemperatures (up to 110°C) that may not normally be exceeded in an auto-clave.11 Their impact on the individual is dose-related, and airborne levelshave been reported from a variety of work environments.

The most commonly reported cases have involved processing of vegetablefibers, fecal material in agriculture, and human waste treatment plants. Mostworker exposures occur in cotton gins/mills, swine confinement buildings,poultry houses, grain storage facilities, sewage treatment facilities, and woodchip processing/saw mills. Other areas include the aerosolizing of machin-ing fluids in metal processing,14 and aerosolized contaminated water sup-plies in hospitals15 and “humidified” office buildings.16 See Table 7.3 for arecap and amplification on the environmental settings in which endotoxinshave been identified at levels significant enough to cause illness.

Symptoms typically involve elevated temperatures. In the cotton indus-try, this is referred to as “mill fever.” Onset of fever is followed by malaise,respiratory distress (e.g., coughing, shortness of breath, and acute air flowobstruction), diarrhea, vomiting, hemorrhagic shock, tissue necrosis, anddeath. However, the latter, more serious symptoms are rare.

Some researchers have also been able to demonstrate acute changes inthe respiratory FEV1 i.e., (forced expiratory volume in 1 second) and suggest


repeated exposures may cause a syndrome similar to chronic bronchitis.18

Other investigators feel that endotoxins add to the virulence of a parasite,enhancing the perils of disease. Once again, hospitals provide a special nichefor such occurrences. Paradoxically, on the same note, it is also thought thatthe endotoxins that threaten one’s health can enhance the body’s immune sys-tem by challenging pathogenic bacteria, viral infections, and cancer.19 Whileincreasing the risk of hypersensitivity disease, endotoxins are a powerful,nonspecific stimulant to the immune system.20

Sampling and Analytical Methodology

Bulk sampling of humidifier reservoirs and other potential endotoxin sourcesis considered the most reliable means of sampling for endotoxins. All samplesshould be collected in sterilized glassware and analyzed promptly, beforemicrobial and subsequent endotoxin amplification can occur. Sterilization ofall glassware and associated laboratory equipment should be baked at 210°Cfor one hour to destroy most pre-existing endotoxin contaminants. Plasticitems should also have been sterilized (e.g., ethylene oxide) or sonication inendotoxin-free 1 percent triethylamine. As they may adsorb large amountsof lipopolysaccharides, sampling supplies made of polypropylene plasticsshould be avoided. Polystyrene is preferred!

Air sampling has been performed with limited success. Attempts havebeen made by dust/particle collection techniques. The methods of collec-tion have included total dust samplers, cascade impactors (size separators),vertical elutriators (used for respirable dust sampling in the cotton industry),cyclones (used for personal respirable dust sampling), and midget impingers(personal samples that collect particles greater than 1 micron in size). Asendotoxins act primarily in the lower region of the lungs (which mostlyinvolves particles of less than 5 microns), “respirable dust samplers” are pre-ferred. For those considering the possibility of viable sampling for bacteria

TABLE 7.3

Occupational Environments Where Endotoxins Have Been Identified andKnown to Pose a Problem16

Cotton gins/millsSwine confinementsGrain storage, handling, and processing facilitiesPoultry barnsSewage treatment and processing facilitiesWood chipping operationsSaw millsFlax millsMachine shopsFiberglass manufacturing19


to get a gauge as to endotoxin levels, endotoxin and viable bacteria sampleshave not been found to correlate.21

Sample collection flow rates have varied, based upon the type of sampler.They have been as low as 2 or 4.5 liters per minute for total dust to as high as7.4 liters per minute with the vertical elutriator. Although not specified, onestudy suggests that in order to detect down to 14 picograms per cubic meter,a minimum of 7.5 cubic meters of air should be sampled.22 Another studysampled at 2 liters per minute for the duration of a workshift, for a volume of960 liters.23 It is quite apparent that laboratories vary in their analytical meth-ods and, therefore, their detection capabilities. For this reason, the laboratoryshould be consulted prior to sampling.

Filter media are also worthy of mention. In one study, recovery of endotoxinfrom four different types of filters was compared to a “no filter” control. Therecovery rates, as reflected in Table 7.4, were extremely poor (e.g., polyvinylchloride membrane filter) to moderate (e.g., mixed cellulose ester membranefilter).21 In a later publication, the same investigator who performed the filtermedia testing proposed the use of “0.4-µm polycarbonate filters” in a stan-dard protocol for sampling endotoxins.24

Upon selection of sampling media, all supplies should be precleaned andsterilized, including the filters and cassettes. Cassettes can be cleaned bysonication in endotoxin-free 1 percent triethylamine, and all other suppliesthat might come in contact with the sample (including the laboratory imple-ments) should be heated at 210°C for 1 hour.23 As ability to perform these pro-cesses is generally not within the realm of the environmental professional,supplies (including filters) are best provided by the laboratory.

After collection, the samples and a field blank (unsampled filter) should besealed in airtight plastic enclosures, placed in a cold storage container, and

TABLE 7.4

Recovery Efficiencies of Endotoxin

Filter TypeRecovery (ng of NP-1

Activity/ ng LPS Added)

Percent Recovered as Compared to the

Controls (%)

Polyvinyl chloride (5.0-µmpore membrane)

0.064 10.8

Polyflon (woven Teflon)Teflon membrane (1.0-µmpore membrane)

0.2060.229

34.438.2

Cellulose mixed ester(0.45-µm pore membrane)

0.252 42.1

Lipopolysaccharide (LPS)control (no filter)

0.599 –

Note: NP-1 = Reference endotoxin.Source: Milton, D., et al. American Industrial Hygiene Association Journal. 51(6):333,

(1990). With permission.


sent immediately to the laboratory. Do not freeze the samples.22 Each of thesamples should be analyzed at the same time, by the same method, withinthe same laboratory.

In the 1940s, endotoxin was measured by injecting rabbits and monitoringincreased body temperatures. The sensitivity was 100 picograms, but rabbitsand preparations were inconsistent.23 Referred to as the Pyrogen Test, thismethod remained in place until the discovery of the unique effects endo-toxin had on the blood cells of the horseshoe crab.

In 1977, the FDA licensed the more sensitive Limulus Amebocyte Lysate(LAL) Assay as an alternative to the Pyrogen Test. An extract is made fromamebocytes of the Limulus polyphemus (or horseshoe crab). In the presence ofendotoxins, clotting occurs. There is a relationship between the amount ofendotoxin present and the rate/amount of clotting.

Samples are extracted and tested according to one of four principal meth-odologies that are based upon blood cell clotting. Extraction methods varyas much as the analytical methods. In a proposed standard method, how-ever, the recommended procedure is to “extract samples in 0.05 M potassiumphosphate, 0.01 percent triethylamine, pH 7.5, using bath sonication.”

Analytical methods include the gel-clot test, calorimetric test, chromoge-nic test, and Kinetic-Turbidimetric Limulus Assay with Resistant-parallel-line Estimates (KLARE) Test. Due to its precision, sensitivity, resistance tointerferences, internal validation of estimates, and ability to provide quan-titative as well as qualitative information, the KLARE test is preferred byresearchers, and there is an attempt to standardize the use of this test aswell.25 However, despite all the studies and research, the choice of method isgoing to be laboratory dependent.


Results are reported in terms of equivalent weight per volume (e.g., ng/mLor ng/m3), equivalent mass (e.g., ng/mg), or potency endotoxin units pervolume (e.g., EU/m3). An endotoxin unit is defined as the potency of 0.10ng of reference standard endotoxin.24 The U.S. Reference Standard EC-5 forendotoxin has a conversion factor of 10 EU per nanagram (ng) of substance.

With the results in hand, interpretation is precarious at best. There havebeen no standardized means for interpreting endotoxin results. Furthermore,variations among laboratories have been as much as 1000-fold. However,results are less than a tenfold difference where a laboratory uses the LALfrom the same lot.26 It thus becomes evident that a single exposure limit isnot feasible, but relative limit values for samples analyzed at the same time,under similar methodologies and LAL lot, are indicated. Many of the moreprominent researchers and commercial laboratories tend toward compara-tive sampling—complaint area(s) verses noncomplaint area(s). When sam-pling for endotoxins in a metal fabrication shop around the cutting fluids, acomparative sample may be collected in an office. When sampling in a turkey


processing plant, a comparative sample may be collected in the administra-tive area. Relative differences should shift simultaneously along with vari-ances created by the different approaches.

According to the American Conference of Governmental IndustrialHygienists (ACGIH) Committee on Bioaerosols, endotoxin levels between 10and 100 times the background levels (e.g., noncompliant areas), coupled withhealth effects consistent with elevated exposures, should be remediated. Thus10 times the background levels is the ACGIH proposed relative limit value.26

A safety factor should be considered. The ACGIH suggests 30 times thebackground levels, in the absence of symptoms.26

Summary

Mycotoxins are toxins concentrated in the cell walls of mold spores—aliveor dead. They are a highly controversial topic brought on by the media,and they are here to stay. They are often implicated by mold types (e.g.,Stachyborys chartarum), but they are not always produced. So, the assump-tion that the toxigenic mold is producing mycotoxins is all too often made.There are now methods available to confirm or deny the presence of manyof the mycotoxins.

Endotoxins are toxins produced by Gram-negative bacteria. Although theyproduce some of the symptoms occasionally encountered in indoor air qualityinvestigations, they are frequently overlooked as a potential problem source.

Both mold and bacterial toxins are infrequently assessed, and it is difficultto trace down a laboratory with the capability to do the analyses. Keep inmind that more than 50 percent of the investigations in one study groupremain unsolved. The investigator should be aware and consider the pos-sibility of microbial toxins when assessing indoor air quality.

References

1. Pleil, J.D. Demonstration of a Valveless Injection System for Whole Air Analysis of Polar VOCs. Proceedings of the 1991 International Symposium on Measurementof Toxic and Related Air Pollutants. Air and Waste Management Association,Pittsburgh, Pennsylvania (1991).

2. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in the Indoor Air Environment Mycotoxins. ACGIH, Cincinnati, Ohio (1989).

3. Sheldon, B.G. Social Security Building Incident Where Settlement Is Alleged to Have Been Quite Expensive (Oral communication). PathCon Laboratory, Norcross,Georgia (July 1995).


4. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999),p. 24–3.

5. Cox, C.S., and C. Wathes. Bioaerosols Handbook. CRC/LewisPublishers, BocaRaton, Florida (1995), p. 375.

6. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), p. 90.7. Cox, C.S., and C. Wathes. Bioaerosols Handbook. CRC/Lewis Publishers, Boca

Raton, Florida (1995), pp. 375–6.8. Tuomi, T., et al. Applied Environmental Microbiology. 66(2) (2000), pp. 1899–1904.9. Aflatoxin Nature’s Most Potent Carcinogen (Handout). Neogen Corporation,

Lansing, Michigan (1996).10. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999),

p. 24–4.11. ACGIH Committee on Bioaerosols. Guidelines for the Assessment of Bioaerosols in

the Indoor Air Environment Endotoxins. ACGIH, Cincinnati, Ohio (1989).12. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), p. 78.13. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999).14. Gordon, T. Acute Respiratory Effects of Endotoxin Contaminated Machining

Fluid Aerosols in Guinea Pigs. Fundamental and Applied Toxicology. 19:117–23(1992).

15. Burrell, R. Human Responses to Bacterial Endotoxin. Circulatory Shock. 43:13753 (1994).

16. Jacobs, R.R. Airborne Endotoxins: An Association with Occupational LungDisease. Applied Industrial Hygiene. 4(2):50 (1989).

17. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999),p. 23–2.

18. Reynolds, S.J., and D. Milton. Comparison of Methods for Analysis of AirborneEndotoxin. Applied Occupational Environmental Hygiene. 8(9):761–7 (1993).

19. Jacobs, R.R. Airborne Endotoxins: An Association with Occupational LungDisease. Applied Industrial Hygiene. 4(2):52 (1989).

20. Rietschel, E.T., and H. Brade Bacterial Endotoxins. Scientific American. 267(2):55–61(1992).

21. Milton, D., et al. Endotoxin Measurement: Aerosol Sampling and Applicationof a New Limulus Method. American Industrial Hygiene Association Journal.51(6):331–7.

22. Reynolds, S.J., and D. Milton. Comparison of Methods for Analysis of AirborneEndotoxin. Applied Occupational Environmental Hygiene. 8(9):762 (1993).

23. Milton, D., et al. Endotoxin Measurement: Aerosol Sampling and Application ofa New Limulus Method. American Industrial Hygiene Association Journal. 51(6):333(1990).

24. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), p. 83.25. Ibid., p. 82.26. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999),

p. 23–10.

Section III

Chemical Unknowns and Gases

135

8VolatileOrganicCompounds

In 1995 the National Institute for Occupational Safety and Health (NIOSH)reported 17 percent of all its indoor air quality surveys had identified volatileorganics as either the cause of or contributor to the indoor air quality com-plaints. Many office spaces have residual organic components in the air fromconstruction, renovation, maintenance, janitorial, chemical usage/process-ing (e.g., spray painting associated with marketing projects), and pest controlactivities. There is also off-gassing from new furnishings, building materials,and office supplies/equipment. Some of the organics may originate from thegrowth of microbes. Tobacco smoke, deodorants, and perfumes contribute tothe total organic loading.

Some indoor chemical contaminants originate outdoors. Outdoor con-taminants enter the indoor air predominantly through the fresh air intakebut may also enter through structural penetrations or porous structural sur-faces. There may be an activity or activities involving chemical within thebuilding whereby the chemicals are exhausted on the roof, entrained in theair currents, and reenter the building through the fresh air intake. This is notas frequently encountered as chemicals emitted from other sources in thevicinity of the building.

Automobile exhausts and industrial pollutants prevail in large cities andaround industrial plants. Even food manufacturing operations have beenknown to generate organic chemicals. Environmental organic compoundsalso evolve from nature’s store of plant life.

Industrial activities generate organic air pollutants both inside and out-side. Although most of these chemicals are known, some are by-productsof multiple-chemical processing and chemical treatments. Stack exhaustsmay service several areas with different chemical contributions, and com-plex chemical reactions in the stacks result in complex chemical mixtures inambient air.

Incidents of chemical storage fires or petrochemical explosions result inthe release of unknown organic by-products. Fires in transport systems andbuildings result in the release of unknowns. The possibilities are infinite!

As defined by the U.S. Environmental Protection Agency (EPA) volatileorganic compounds vaporize (become a gas) at room temperature. Thisincludes all organic compounds with up to seventeen carbons in theirmolecular structure that have a boiling point up to 250°C.


Health Effects and Occurrences

Industrial exposures to volatile organic compounds (VOCs) are generally10 to 100 times that of nonindustrial home and office environments. Homeand office environments are typically 2 to 100 times higher than that foundoutside. A reasonable line of logic would dictate that industrial exposureswould result in more health complaints than home and office exposure. Yetthis is not the case.

Many environmental professionals ascribe the complaints to exposures toa medley of chemicals and to the lack of adequate dilution in indoor air. Thechemicals are trapped and recycled with the close environments.

Indoor nonindustrial air environments may consist of up to three hundreddifferent chemicals, an amalgam that certainly complicates an investigation,and the sources are certainly no less complicated. Indoor VOCs may origi-nate from one or a combination of the following:

• Ambient outside air (e.g., benzene from automotive exhaust and vaporrelease from gasoline service stations, especially in large cities)

• Off-gassing of chemicals from furnishings (e.g., formaldehyde fromdesks made of particleboard)

• Emissions from office equipment (e.g., toners from copy machines)• Cleaning and maintenance products• Construction, demolition, and building renovation activities (e.g.,

painting the walls)• Personal hygiene products (e.g., perfume)• Poorly contained sewage gases (e.g., leaking sewer vents)• Contaminated HVAC system (e.g., chemical storage in a return air

room)• Pesticides and insecticides• Environmental air pollution (e.g., automotive exhaust)• Industrial emissions (e.g., particleboard manufacturing)• Commercial activities (e.g., automotive painting, roof asphalting,

and dry cleaning exhausts)

For a list of some of the chemicals frequently found in indoor air quality andtheir sources, see Tables 8.1 and 8.2.

Although the health effects of VOCs are chemical dependent, the effectsof low-level, nonindustrial exposures to the total organic compound com-posite generally encountered in indoor air quality are relatively consistent.

VolatileOrganicCompounds 137

Symptoms typically involve one or a combination of the following:

• Headache• Irritation of the eyes, nose, and throat• Lightheadedness• Nausea

TABLE 8.1

Common Indoor VOCs and Their Sources

Pollutant Indoor Sources

Formaldehyde Germicide, pressed-wood products, foam insulation (UffI), hardwoodplywood, adhesives, particle board, laminates, paints, plastics,carpeting, upholstered furniture coverings, gypsum board, jointcompounds, ceiling tiles and panels, nonlatex caulking compounds,acid-cured wood coatings, wood paneling, plastic/melaminepaneling, vinyl floor tiles, parquet flooring

Benzene ETS, solvents, paints, stains, varnishes, fax machines, computerterminals and printers, joint compounds, latex caulk, water-basedadhesives, wood paneling, carpets, floor tile adhesives, spot/textilecleaners, Styrofoam, plastics, synthetic fibers

Carbon Tetrachloride Solvents, refrigerant, aerosols, fire extinguishers, grease solventsTrichloroethylene Solvents, dry-cleaned fabrics, upholstered furniture covers, printing inks,

paints, lacquers, varnishes, adhesives, fax machines, computer terminalsand printers, typewriter correction fluid, paint removers, spot removers

Tetrachloroethylene Dry-cleaned fabrics, upholstered furniture coverings, spot/textilecleaners, fax machines, computer terminals and printers

Chloroform Solvents, dyes, pesticides, fax machines, computer terminals andprinters, upholstered furniture cushions, chlorinated water

1,2-Dichlorobenzene Dry-cleaning agent, degreaser, insecticides, carpeting1,3-Dichlorobenzene Insecticide1,4-Dichlorobenzene Deodorant, mold and mildew control, air fresheners/deodorizers,

toilet bowl and waste can deodorizers, mothballs and moth flakesEthylbenzene Styrene-related products, synthetic polymers, solvents, fax machines

computer terminals and printers, polyurethane, furniture polish,joint compounds, latex and nonlatex parquet flooring

Toluene Solvent, perfumes, detergents, dyes, water-based adhesives, edge-sealing, molding tape, wallpaper, joint compounds, calcium silicasheet, vinyl-coated wallpaper, caulking compounds, paint, carpeting,pressed-wood furnishings, vinyl floor tiles, paints (latex andsolvent-based), carpet adhesives, grease solvents

Xylene Solvents, dyes, insecticides, polyester fibers, adhesives, jointcompound, wallpaper, caulking compounds, varnish, resin andenamel varnish, carpeting, wet-process photocopying, pressed-woodproducts, gypsum board, water-based adhesives, grease solvents,paints, carpet adhesives, vinyl floor tiles, polyurethane coatings


TABLE 8.2

Case Study of VOCs in Indoor Air, Suspect Sources, and Direct ReadingInstruments1

Limits of Concern Direct Reading

ACGIH ASHRAEa Suspect Instrument Response

Compound (ppm) (mg/m3) (mg/m3) Source(s) FIDb PIDc

Pentane 600 1700 – natural gas 65% [email protected] 50 176 7 rubber cement 75% [email protected] 100 343 – solvent 85% 1.40@106eV

Decane – – – copy toner 75% [email protected] 0.5 1.6 0.02 paints/gasoline 150% [email protected] 20 75 0.3 paints/gasoline 110% [email protected] 100 431 0.7 paints/gasoline 115% 0.43-0.59@

10.6eVLimonene – 560d – lemon-odor cleaner – –Acetone 500 1188 – solvent 60% [email protected] (MEK) 200 590 – paints/solvent 80% [email protected] isobutylketone

50 205 – resins/solvent 100% [email protected]

Tetrahydrofuran 50 148 – plastic pipe cleaner – [email protected] cellosolve(2-methoxyethanol)

0.01 0.32 – solvent/cleansers – [email protected]

Butyl cellosolve(2-butoxyethanol)

20 97 – solvent/cleansers – [email protected]

Cellosolve(2-ethoxyethanol)

5 18 – solvent/cleansers – [email protected]

Carbon tetrachloride 5 31 0.04 solvent/cleansers 10% [email protected](perchloroethylene)

25 170 0.035 solvent/cleaners 70% [email protected]

1,1,1-Trichloroethane 10 55 1 office partitions 105% [email protected] 113 1000 1250 – coolant 90% 1.0 @ 11.7eVn-Nonane 200 1050 – synthetics/gasoline 90% [email protected] chloride 50 174 – polyurethane

foam/plastics90% [email protected]

Trichloromethane(chloroform)

10 49 0.03 aerosolpropellants/plasticsdry cleaning

65% [email protected]

1,4-Dichlorobenzene(p-dichlorobenzene)

10 60 0.8 fumigant/insecticide

113% [email protected]

a From ASHRAE 189.1 List of Target Volatile Organic Compounds.b As calibrated to methane with Foxboro FID.c As calibrated to isobutylene with RAE Systems MultiRAE.d WHO recommended exposure limit in ASHRAE 62 (1989).2


The EPA adds to the list some less commonly encountered symptoms:2

• Nasal congestion• Coughing• Wheezing and worsening of asthma problems• Fatigue• Lethargy• Cognitive impairment• Personality change

Health effects resulting from industrial and commercial exposures involveconsiderably higher exposures to a wide variety of known chemicals. Thehealth effects are more pronounced and chemical specific. If these higherexposure levels are likely (e.g., exhausted chemicals from a manufacturingoperation), the health effects may be more extensive. The investigator shouldassess impact based on the known health effects of the suspect chemical(s)identified during the preliminary assessment. Exposures to different spe-cifically identified chemicals will result in more specific symptoms than thatwhich is generalized for a total organic composite.

People who are chemically sensitive or chronically ill, the elderly, andinfants will also require special consideration, especially if exposures are24 hour (e.g., residences and nursing homes). These people are not normallylocated in office and other work environments.

Air Sampling Strategy

A clear, concise air sampling strategy is as important as the actual sam-pling. If samples do not represent the complaint times, area, and condi-tions, there is little point in taking a sample. It may appear obvious tomany that the when, where, and how are only logical. Yet logic is some-times elusive.

When to Sample

At a minimum, samples should be taken during a time or times when com-plaints are their greatest and for a period of time sufficient to capture anadequate sample. This may sound like a simple concept to many readers, yetinvestigators often take samples during periods deemed most convenient forthe environmental professional. Sometimes these “convenient times” do notfall within the time period during which there are complaints.


Where to Sample

Identify an area or areas central to where complaints have occurred. At aminimum, a worst-case air sample should be taken where the complaint(s)are the greatest. A note of caution: The most complaints may be associatedmore so with an individual than with the environment. In a large officebuilding, clusters of complaints are more reliable. In a small office or resi-dence, the occupant(s) may be able to identify an area or areas they believe tobe the source of their perceived poor indoor air quality.

After determining the worst-case complaint area(s), determine if there is anoncompliant area or area of perceived good indoor air quality. Where a non-compliant area can be identified, an indoor air sample should be considered.There may be activities or conditions in the complaint area(s) that are notencountered in the noncompliant area(s). These activities or conditions maynot be readily apparent or come to light unless the environmental profes-sional compares the complaint sample results with the noncompliant sampleresults. Noncomplaint area sampling is not vital, but it is a good practice.

It is, however, advisable that the environmental professional perform com-parative outdoor air samples in conjunction with noncompliant control sam-ples or as a stand alone. In large office buildings, outdoor air samples shouldbe taken at the HVAC fresh air intake for the area in question or whereverthere is air movement from outdoors to inside the building in the vicinity ofthe complaints (e.g., high traffic entrances to a building and open windows).In small offices and residences, there may not be an HVAC fresh air intake.Where this is the case outdoor air samples may be taken outdoors in thevicinity of high traffic entrances. Outdoor air comparison samples are vitalto interpreting the indoor air environment!

Worst-case air sample sites and comparative noncompliant/outdoor controlareas are not an easy task to identify. In large office buildings, questionnairesand area charts areas are a must. For examples of comparative sampling, seeFigures 8.1 through 8.4.

As for physical placement, samples should be collected as area samples, notpersonnel samples, unless the circumstances indicate otherwise. Placementof the sampler should be within the breathing zone of those occupying thearea of concern, not in a corner or on a wall, but in the vicinity of their nor-mal activity (e.g., sitting at a desk). Also consider the facility: A child-carecenter will have a different placement than a mail-sorting center.

Take prolific notes regarding each sample site, documenting observationsand conditions (e.g., proximity of air supply diffusers, equipment, machines,windows, doors, space heaters, pedestal fans, home air purifiers, plants, tem-perature, and humidity). If blowing directly on the sampler, the effects ofthe air supply should be recorded. Stagnant air pockets may impact sampleresults. Proximity of equipment (e.g., copy machines) and activities (e.g., glu-ing and painting) may be important. There is no such thing as too manynotes.


How to Sample

There is no one-size-fits-all technique for sampling volatile organics. As asingle panacea does not exist, the investigator should become familiar withthe various screening and sampling methods and apply them according tospecific project needs.

Rationale for Total VOC Screening (As Opposed to Component Identification)

Screening for VOCs is used for determining need for more extensive, costlyapproaches. The cost for the quantification of total VOCs is one-fifth toone-tenth the cost for identification, and if a worst-case complaint area isassessed, the number of samples to be analyzed can be minimized, again

Abu

ndan

ce

700000

500000

300000

100000

0

Abu

ndan

ce

700000

500000

300000

100000

0

2.00

THF

THF

n-C1

4H30

n-C1

4H30

n-C1

1H24

Lim

onen

e

1,1,

1-tr

ichl

oroe

than

e

n-C1

5H32

n-C1

5H32

6.00 10.00 14.00 18.00 22.00

2.00 6.00 10.00 14.00 18.00 22.00Time

Time

OFFICE AREA

PRODUCTION AREA

FIGURE 8.1Adjacent office area vs. point source production area. As demonstrated in the GC/MS printout,some of the organics in the office space mimic that of the production area, but most of the VOCsoriginated in the office area. (Courtesy of NIOSH, Cincinnati, Ohio)3


keeping down the overall project cost. If the results are low additional ana-lytical fees may be circumvented. This brings us to the all-consuming ques-tion: How low is “low,” and what are acceptable risks?

There are no mandated acceptable limits for total VOCs. Thus, the environ-mental professional must decide on an action limit to serve as a “go, no-go”decision guide prior to proceeding with the expense of identification andmore extensive sampling. There are no established acceptable limits for totalVOCs. Thus, the environmental professional must decide on his/her actionlimit prior to proceeding.

Most environmental professionals use an action level of 500 µg/m3 (0.5 mg/m3). This 500 µg/m3 limit has been adopted by several state governments andhas become the LEED maximum concentration, or limit, for total VOCs. Yet itis noteworthy that some professionals choose an even lower action level.

For some VOCs toxic exposure limits are not as low as irritation exposurelevels, and not all irritant/toxic VOCs have an exposure limit. For example,phenol has an American Conference of Governmental Industrial Hygienists(ACGIH) exposure limit of 5 ppm (19 mg/m3). Some sensitive individuals

Abu

ndan

ce

900000

700000

500000

300000

1000000

Abu

ndan

ce

900000

700000

500000

300000

1000000

2.00 6.00 10.00 14.00 18.00

2.00 6.00 10.00 14.00 18.00D

imet

hylb

enze

nem

etha

nol

Lim

onen

e

Met

hyl s

tyre

ne

Tolu

ene

Tolu

ene

Met

hyl m

etha

cryl

ate

Hex

ane

Hex

ane

Etha

nol

Etha

nol

Time

Time

OFFICE AREA

OUTDOOR CONTROL

FIGURE 8.2Office area vs. outdoor control. As demonstrated in the GC/MS printout, some of the organicsin the office area mimic the outside area with the addition of indoor source VOCs, but mostoriginated in the office space. (Courtesy of NIOSH, Cincinnati, Ohio)3


can experience irritation at levels as low as 0.19 mg/m3. If the 0.5 mg/m3

action level were applied and no further VOC identification were indicated,phenol would not be identified and the search for unknowns would be mis-directed to other areas. There are also many chemicals for which there are noestablished exposure limits. 1-Methyl-2-pyrrolidinone, an irritant thought tobe associated with 4-phenylcyclohexene and styrene butadiene rubber latexcarpet backing, does not have any published exposure limits. Thus, someprofessionals choose a limit of 250 µg/m3 (0.25 mg/m3).

Air Sampling and Analytical Methodologies

As all environmental professionals are not the same, air sampling and ana-lytical methods differ from one laboratory to the next. Air sampling and ana-lytical methods for VOCs, identified and not identified, have been developedand published by the Environmental Protection Agency (EPA), Occupational

Abu

ndan

ce

1400000

1000000

600000

200000

0

Abu

ndan

ce

1400000

1000000

600000

200000

0

2.00 6.00 10.00 14.00

Lim

onen

eLi

mon

ene

1,1,

1-tr

ichl

oroe

than

e

C6 alkanes

2.00 6.00 10.00 14.00

Time

Time

COMPLAINT AREA

NONCOMPLAINT AREA

FIGURE 8.3Complaint area vs. noncomplaint area. As demonstrated in the GC/MS printout, the source ofthe VOCs was found to be generated in the vicinity of the complaint area, not in the noncompli-ant area and not outdoors. (Courtesy of NIOSH, Cincinnati, Ohio)3


Safety and Health Administration (OSHA), and National Institute forOccupational Safety and Health (NIOSH). Beyond the government agenciescommercial laboratories develop their own protocols in order to accommo-date special client needs and advance new technologies, and instrumen-tation technology is constantly evolving to accommodate requirements ofenvironmental professions.

All commercial laboratories are not the same. They have different capabili-ties and depth of knowledge. Many laboratories perform very basic chemicalanalyses (e.g., solid sorbent analysis by gas chromatography). Some performmore extensive analyses (e.g., solid sorbent analysis with gas chromatogra-phy/mass spectrometry), and a limited number of these provide evacuatedcontainers. In brief, few laboratories can do it all, and even fewer performresearch and develop methods to accommodate special client requests. Theinformation herein is intended to familiarize the reader with publishedmethodologies and limitations.

7000000

5000000

3000000

1000000

02.00 6.00 10.00 14.00 18.00 22.00

2.00 6.00 10.00 14.00 18.00 22.00

Abu

ndan

ce

7000000

5000000

3000000

1000000

0

Abu

ndan

ce

Tric

hlor

ofluo

rom

etha

ne

Met

hyl e

thyl

ket

one

p-D

ioxa

neM

ethy

l iso

buty

l ket

one

Tolu

ene

Tolu

ene

Xyle

ne Styr

ene

1-M

ethy

l-2-p

yrro

lidin

one

2-Et

hylh

exyl

acry

late

Time

Time

INSIDE NEW TRUCK

OUTSIDE CONTROL

FIGURE 8.4Inside new truck vs. outside control. As demonstrated in the GC/MS printout, toluene wasfound outside the truck, and all the other VOCs originated inside the truck. (Courtesy ofNIOSH, Cincinnati, Ohio)3


Solid Sorbents and Air Sampling Pumps

The preferred, most reliable solid sorbent sampling technique, both qualita-tively (identification) and quantitatively (airborne levels determined), occurswhere the organic compounds have already been identified. Either specificcompounds are known to be present (e.g., toluene from recently appliedpaint), or they are suspect (e.g., potential 1,1,1-trichloroethane from officepartitions). Suspect chemicals are often targeted based on odors, complaintsymptoms, or probable sources. Yet all too often the offending chemical isunknown and there are multiple suspects, so screening for total VOCs andidentification of components becomes the option of wise resort.

Solid sorbent sampling is useful for both screening for total VOCs and foridentification of components. Air sampling is an active approach wherebyair is drawn through a solid sorbent that captures (i.e., collects) airborne con-taminants that are then analyzed by a laboratory. The two most widely usedmethods are NIOSH Method 1500 and EPA Method TO-17. Although the EPATO-17 is all inclusive for most VOCs, NIOSH 1500 (which has limited captureability, limited VOC retrieval) has been the most frequently used method,especially for screening, due to convenience and familiarity.

NIOSH Method 1500

NIOSH Method 1500 for hydrocarbons involves collection of air samplesusing activated coconut shell charcoal (contained within a glass tube), des-orption with carbon disulfide, and analysis by gas chromatography using aflame ionization detector. Many VOCs that are generally of concern in indoorair quality testing are adsorbed onto (captured by) charcoal solid sorbent,but some are not collected. If elevated levels of any given VOC air contami-nant are not captured and if that specific VOC is the source of complaints,the uncollected VOC will not contribute to the total VOCs, and it cannot besalvaged if further identification of the total VOC components is indicatedduring the screening process. It will go undetected. For example, phenoloff-gassing from phenol-formaldehyde particleboard could cause irritation,while the capture sorbent for phenol is XAD-2 solid sorbent, not charcoal.

In NIOSH 1500 the captured VOCs are desorbed with carbon disulfide.Whereas carbon disulfide is very effective at extracting captured VOCs,there are some that require a different solvent. If the proper solvent is notused some VOCs will be missed. For instance, acrylonitrile requires metha-nol for desorption. If it was collected but not retrieved from the solid sorbent,exposures to the eye, nose, and throat irritant acrylonitrile will remain unde-tected and undocumented.

To go one step further, in a 1993 study performed by NIOSH the effec-tiveness of thermal desorption (e.g., EPA Method TO-17) over chemical des-orption was challenged. Two separate sorbents were used to sample within


the same time period and same sample site (e.g., a rubber molding facility).One was sampled by thermal desorption tube with a carbon-based sorbentand analyzed by gas chromatography/mass spectrometry (GC/MS). Theother was sampled by charcoal tube, chemically desorbed, and analyzedby GC/MS. The results favored thermal desorption sampling and analyti-cal approach over the other.2 Compounds missed in the chemically des-orbed charcoal tube included aliphatic amines, sulfur dioxide, and carbondisulfide. Since it is used as the desorption compound for most chemicalextractions from charcoal tubes, carbon disulfide would have been over-looked as an indoor air contaminant had chemical desorption be used. SeeFigure 8.5.

The failures of NIOSH 1500 can be troubling. Too many volatile organiccompounds that could cause health complaints may be overlooked. The alter-native, EPA Method TO-17 (also NIOSH Method 2549), is more all-inclusiveand more reliable. However, TO-17 is three to ten times more costly thanNIOSH 1500.

Time

Time

450000

350000

250000

150000

50000

450000

350000

250000

150000

50000

05.00 7.00 9.00

Abu

ndan

ceA

bund

ance

11.00 13.00 15.00 17.00 19.00

05.00 7.00 9.00 11.00 13.00 15.00 17.00 19.00

C10-C12 branchedalkanes

C10-C12 branchedalkanes

THERMAL DESORPTION

CHEMICAL DESORPTION(Charcoal Desorbed

by Carbon Disulfide Solvent)

FIGURE 8.5Thermal desorption vs. chemical desorption. The GC/MS printout demonstrates the greaterefficiency of thermal desorption over that of chemical desorption. (Courtesy of NIOSH,Cincinnati, Ohio)3


A summary of NIOSH Method 1500 follows:

• Equipment: air sampling pump• Capture media: coconut shell charcoal or Anasorb® 747• Flow rate: 50 to 200 mL/min.• Air volume limits: 2–30 liters• Desorption: carbon disulfide• Reference standard for TVOC: toluene (variable by laboratory)• Field blanks: minimum of one for every ten samples• Analysis: GC–FID (C3–C17; mostly nonpolar organics with boiling

point <220°C)• Limit of detection: 246 ng/sample (variable by laboratory); 68.3 µg/m3

(or 18.1 ppbv toluene) based on four-hour sample at 50 lpm as perOSHA Method 111)

• Special handling and shipping instructions: none

EPA Method TO-17

In EPA Method TO-17, the solid sorbent is a thermal desorption tube (e.g.,Carbopak™) that is either commercially available or specially prepared bythe laboratory (e.g., packed and conditioned in stainless steel or polymerictubes). The multiple sorbent (containing three or more broad spectrum sor-bents) is more all inclusive and captures many VOCs that are not collectedby charcoal tube sampling (e.g., NIOSH 1500) as well as all those that arecollected by charcoal sorbent, and many multiple sorbents collect some ofthe heavier semi-volatile organic compounds (with a boiling point greaterthan 220°C). For example, many multiple sorbents collect the eye and mucusmembrane irritant 1,3-butadiene (a light molecular weight organic that is notcaptured by charcoal), and most multiple sorbents capture the carpet emis-sions irritant 4-phenylcyclohexene (boiling point: 243°C) which is not other-wise collected by charcoal nor retrieved from canisters. See Figure 8.6.

Another advantage to TO-17 is that desorption is not solvent dependent,whereas component retrieval and analysis is desorption solvent dependentwhen sampling with charcoal sorbents. The multiple sorbent tube is hookedup directly to the GC/MS and heated to drive all the captured chemicalsfrom the tube. Once again, the single charcoal sorbent does not allow foranalysis of all that has been captured.

Analysis is then performed in accordance with client instructions. Hereagain each laboratory has a different list of VOCs to be analyzed with specificreference standards. Each list is based on perceived client concerns (e.g., toxicVOC, odors, or irritants), multiple sorbent type, and experience. Most labo-ratories also perform a library search in order to identify other compounds


that may not be on the list. A library search may include up to 750,000 chemi-cals. Much like illegal designer drugs, if you limit a search to that which hasbeen of the past, you may miss that which will be in the future.

The analytical cost, once again, is the greatest objection, and quantifiedidentification of components is more costly than analysis for total VOCs. Onthe other hand, qualitative identification of the components may not resultin an additional fee. Yet the benefit of component identification of significantcontributors to the total VOC medley is a viable compromise while keepingthe cost down.

Another downside to the TO-17 method is that once the sorbent sample hasbeen thermally desorbed, the captured VOCs are gone—unless the labora-tory undergoes splitting/re-collection of the samples as they are analyzed bythe GC/MS. The latter is not performed by all laboratories. Also, if a sampleis being processed and should the electricity surge or fail, the sample may belost. It cannot be retrieved. This may happen one time in one hundred, but itdoes happen. Dual sampling is advisable.

6000000

2000000

0

6000000

2000000

0

6000000

2000000

0

2.00 6.00H

exan

eH

exan

e

Acet

one

Acet

one

Etha

nol

Met

hyle

ne ch

lorid

e

Benz

ene

Benz

ene

1,1,

1-TC

E1,

1,1-

TCE

Hep

tane

Hep

tane

Tolu

ene

Tolu

ene

MIB

KM

IBK

Oct

ane

Buty

l cel

loso

lve

Phen

ol Dec

ane

Lim

onen

e

10.00 14.00

2.00 6.00 10.00 14.00

2.00 6.00 10.00 14.00Time

Time

Time

Abu

ndan

ceA

bund

ance

Abu

ndan

ce

(Traps Least Volatile Organic Compounds)

(Traps Moderately Volatile Organic Compounds)

(Traps Most Volatile Organic Compounds)

1st LAYER

2nd LAYER

3rd LAYER

FIGURE 8.6Multibed thermal desorption. The GC/MS printout demonstrates volatile organic compoundscaptured in each of the layers. (Courtesy of NIOSH, Cincinnati, Ohio)3


A summary of EPA Method TO-17 follows:

• Equipment: air sampling pump• Capture media: thermal desorption tube (e.g., Carbopak™), which

generally requires laboratory cleaning and conditioning• Flow rate (TO-17): 10 to 50 mL/min.• Flow rate (laboratory experience/preference): 50–100 mL/min.• Air volume limits: 1–6 liter (variable higher limits based on multibed

sorbent, and required reporting limits may be as high as 10 liters)• Desorption: thermal desorption• Reference standard for total VOC: toluene (variable by laboratory)• Field blanks: minimum of one for up to ten samples in any given

sampling period• Analysis: TD–GC–MS (C5–C17; polar and nonpolar organics with

boiling point <250°C)• Limit of detection: 0.1 ppm/1 liter sample; 0.4 µg/m3 (toluene) based

on a 1 liter sample• Special handling and shipping instructions: laboratory dependent

(some require ice pack for shipping)

All VOC analyses require a reference standard for the purpose of quan-tifying each of the chemical components. The reference standard for totalVOCs (a mix of unknown components) is generally toluene (or an organicthat has a similar molecular weight such as n-hexane). Laboratory prefer-ences do vary, and the reference standard used for quantifying total VOCsaffects the reported results. True quantification can only be obtained byusing a reference compound for each component. Thus, quantification oftotal VOCs is only a “ballpark number” and varies by laboratory and refer-ence standard used.

Passive Organic Vapor Monitors

Passive air diffusion monitors are lightweight badge assemblies that rely onnatural air currents (rather than air sampling pumps) to allow air to diffusethrough a protective membrane and be collected by a solid sorbent containedwithin a badge (e.g., disk-shaped plastic container). Organic vapor monitorsare easy to use but slow, and they are similarly limited by the same param-eters as air sampling using charcoal (e.g., NIOSH 1500).

For more than twenty years organic vapor monitors have had a charcoalsorbent that adsorbs organic vapors from the air at a low capture rate. Eachcompound has a unique sample rate and diffusion coefficient that is usedto calculate the final concentration of that component. For example, the 3M


Organic Vapor Monitor sampling rate for p-tert-butyltoluene is 20.7 mL/min., and the sampling rate for acrylonitrile is 48.2 mL/min.4

When there are multiple components some compounds will displace oth-ers and the full spectrum of indoor air VOCs may disappear. For instance,nonpolar n-hexane will displace the more polar isopropanol.

As all passive monitors rely on diffusion and natural air movement, thereis a minimum air flow necessary in order to prevent “starvation” at the sur-face of the sampler. The minimum air movement, around 20 feet per second,is generally quite low but the environmental professional should be awareof this limitation. For example, a building that has been vacated and has noair movement, the air movement may be nonexistent and passive samplingis likely to be ineffective. Air starvation is a minor limitation, not normallyencountered when using an air sampling pump.

Another limitation of the passive monitors is sampling rate and sampleduration. For detection levels comparable to air sampling pump flow rates of50 liters/min. and 200 liters/min., an organic vapor monitor sampling timemust be two times and eight times the pump air sampling duration (basedon the sampling rate range of 20.7 to 48.2 liters/min.). For example, an organicvapor monitor would have to be exposed for eight hours in order to collectthe same sample as a four-hour air sampling flow rate of 50 liters/min.

AnalysisoforganicvapormonitorsisaddressedinOSHAMethod111,whichissimilartoNIOSHMethod1500.Desorptionisby60/40N,N-dimethylformamide/carbon disulfide, and analysis is by GC–FID. All things considered, the organicvapor monitor does require a longer sampling duration.

A summary of 3M and SKC Organic Vapor Monitor Method follows:

• Equipment: organic vapor monitor (with the protective membraneintact during sampling)

• Capture media: charcoal• Air volume limits: 2–30 liters• Desorption: carbon disulfide• Reference standard: toluene (variable by laboratory)• Field blank: minimum of one for up to ten samples in any given

sampling period• Analysis: GC–FID (C3–C17; mostly nonpolar organics with boiling

point <220°C)• Limit of detection: 246 ng/sample; 309 µg/m3 (or 82 ppbv toluene) based

on four-hour sample with a 3M 3520 (as per OSHA Method 111)• Special handling and shipping instructions: none

In order to address the sampling duration discrepancies with passive moni-tors, the Radiello Passive Sampling System is an emerging technology in theU.S. Having been used in Europe for more than ten years for environmental


and indoor air quality sampling, the Radiello has not been acknowledgedby the EPA or NIOSH. It is, however, being introduced by some laboratorieswithin the U.S.

The Radiello passive monitors are typically tube-shaped and have a higherdiffusion rate than that of the SKC and 3M Organic Vapor Monitors. Two ofthe more commonly used Radiello passive monitors allege rapid samplingtimes. The Radiello (RAD) 130 is a passive diffusion monitor that is com-parable to charcoal sorbent organic vapor monitor. Yet the RAD 130 allegesa faster sampling time. The RAD 145 is an interesting variation to passivesampling. It has been adapted to allow for diffusion onto a multibed sorbentand can be used as a passive sampler for EPA Method TO-17. The RAD 145sampler can be thermally desorbed and analyzed by GC/MS.

According to some U.S. laboratories the RAD 145 is a mid-range (C5–C10)sample device and is being used in some indoor air quality studies. Its effi-cacy has yet to be fully tested, and the Radiello diffusion monitor will notcollect the higher molecular weight, higher boiling point compounds suchat that which is encountered in carpet emissions. In other words, it will notcollect 4-phenylcyclohexene.

As of the writing of this book the Radiello passive diffusion samplers haveyet to be recognized by the EPA and have not been widely accepted for usein indoor air quality studies within the United States. Should one desire toutilize this method the number of laboratories performing this analysis islimited, and the approach is not widely recognized by the environmentalprofessionals.

Evacuated Ambient Air Containers

In accordance with EPA Method TO-15 sample collection is performed byevacuated air containers (also whole air samplers) that suck in and retainambient air, all organic components. When a client asks, “Can’t you just suckin all the air?” Well, yes, you can! It is the analytical procedure that limitsidentification of all components in the air. For example, formaldehyde maybe present in the collected air, but it is poorly retrieved and analyzed byGC/MS due in part to its low molecular weight. Aldehydes are best cap-tured by specialty sampling media and analyzed by different methods (seeChapter 12, “Formaldehyde”).

Heavier VOCs tend to settle in the ambient air containers and may settleand be difficult to retrieve. Such is the case with 4-phenylcyclohexene. Themultibed sorbents (e.g., TO-17) can capture and release the heavier VOCs.Also, inorganics may be retained within the ambient air container but arenot analyzed by GC/MS.

Evacuated air containers include evacuated canisters (e.g., SUMMA-likecanister) and ambient air sampling bags (e.g., Tedlar® bag). While the othersare adaptations, stainless steel evacuated air canisters are the equipment ofchoice as described in EPA Method TO-15.


Whole Air Canisters

Stainless-steel whole air canisters come in various sizes (ranging from 0.85 to33 liters in volume). The most common size used in indoor air quality stud-ies is 6 liters. The original SUMMA® stainless steel canisters were chemicallytreated to prevent rusting and minimize organic adherence to the surfaceof the container. Yet sample stability was not all that it could be. Today’sstainless steel canisters (sometimes referred to as SUMMA-like canisters)are electropolished to bring the nickel and chromium to the surface, makingthe inside of the canister inert with a mirror-like finish. Silica-treated stain-less steel canisters are electropolished then treated with fused silica, a toughinterior glass-like surface that will not crack or break under rough field andshipment handling. Wherein ideal for TO-15, electropolished canisters areunreliable for collecting sulfur-containing/brominated compounds that tendto adsorb, or stick, to the inner surface of electroplated stainless steel canistersand are poorly retrieved for analysis. Yet for every problem there is a solution.The solution is the special silica-treated evacuated canister. See Figure 8.7.

FIGURE 8.7SUMMA-like evacuated air canister—silica-coated canister best for low-level detection of sul-fur-containing compounds. (Courtesy of Restek Corporation, Bellefonte, Pennsylvania.)


According to Restek, SilcoCan canisters provide a stable environment foranalysis of sulfur-containing VOCs as low as 1 ppbv. In one study involv-ing the same air collection by two different canisters, the silica-treated can-ister analysis provided a detection of 5 ppbv hydrogen sulfide, whereas theelectropolished canister provided a detection of 100 ppbv. The odor thresh-old for hydrogen sulfide is less than 9 ppbv.5 If a sulfide-containing organicis contributing to the odor in an indoor air quality study, the retrieval froman electropolished canister is not as good as that of a silica-treated canister.Hence, if an electropolished canister is used instead of a silico-treated can-ister, the detection will likely not be low enough to identify any componentsulfur-containing compounds (e.g., mercaptans or off-gassing hydrogen sul-fide from tainted Chinese drywall). Wherein sulfur-containing compoundsare present in levels below 5 ppbv, there are no methods available that cantrump this claim.

Prior to use each canister must be cleaned, conditioned, and prepared bya laboratory that has canister analytical capabilities. The canister cleaningprocess takes up to 24 hours per canister, so the laboratory will require somelead time. As part of the planning process, the inlet may also be fitted with aflow control, or critical orifice, if a predetermined extended sampling dura-tion (e.g., four hours) is required. Otherwise, without a calibrated criticalorifice (provided by the laboratory), a grab sample will be collected. A grabsample will take less than 30 seconds in a 6-liter canister.

When the valve is opened the ambient air is drawn into the canister byvacuum until the canister pressure and ambient air pressure are equal.To determine if this has occurred refer to the canister gauge that is avail-able through the laboratory (upon special request). Start and finish timesshould be recorded along with pertinent sample conditions (e.g., tempera-ture, relative humidity, and barometric pressure if available) and locationdetails.

Collected air samples are auto injected into a GC/MS. Some laboratoriescryogenically treat each sample as it is injected to concentrate the sample andattain a greater level of detection. The amount of air sample injected may beanywhere from a 100-milliliter portion to 1 liter of the sample, depending onsample volume collected, the laboratory standard procedures, and whetherthe sample is to be cryogenically concentrated. The higher the volume of airsampled, the higher the limit of detection. Some laboratories will analyze200 to 250 milliliters of air if not cryogenically treated, finding that the limitof detection is more than sufficient to not require concentration. Other labo-ratories choose to or the environmental professional may request a samplebe cryogenically concentrated whereby a 1-liter of air is cryofocused to getgreater detection limits. Thus, 1 liter of air is the greatest volume of air thatcan be analyzed in accordance with EPA TO-15. Wherein the canister vol-ume exceeds the air volume analyzed, air samples can be reanalyzed shouldthe first analysis meet with misfortune or should the environmental profes-sional require additional analyses.


A summary of EPA Method TO-15 follows:

• Equipment: evacuated air container• Capture media: not applicable• Flow rate: instant grab sample or long duration up to three days

(flow control valve)• Air canister size: 1–6 liters• Desorption: automated injection of 200 milliliters of sampled air,

irrespective of canister size• Reference standard: toluene (variable by laboratory) for total VOCs• Analysis: GC/MS (C3–C12; organics with boiling point <220°C)• Limit of detection: 0.5 ppbv/sample (variable by laboratory)• Special handling and shipping instructions: none

A word of caution is in order for requesting cryofocusing on an indoor airquality sample. The detection levels for a straight GC/MS analysis are extremelylow already without cryogenic concentration, and wherein a component VOCapproached the ppmv concentration, the analysis of similar low level organiccomponents may be obscured as cryofocusing detection limits dip parts pertrillion (pptv). Cryofocusing is not needed wherein systemic health symptomsand irritation are the concerns. The systemic health concerns and irritation lev-els will be in the ppb or ppm, not ppt, range. Yet cryofocusing may be beneficialwhere the odor threshold of some VOCs dips below 1 ppb. For example, themean odor threshold for mercaptans has been reported as 500 ppt, individu-ally as low as 2 ppt. The mean odor threshold for ethyl acrylate is 240 ppt. Theodors are described as that of rotten cabbage and sweet/ester/plastic, respec-tively.5 Could not the new car smell be due in part to ethyl acrylate?

Ambient Air Sampling Bags

Ambient air sample collection bags are special sampling equipment con-structed of synthetic material (e.g., Tedlar and Teflon). At first blush the sam-pling bags are inexpensive to purchase and can be purchased in bulk forshortsighted planning projects. Simple Simon stops here!

Organic components may adhere to the surface of the bag or may off-gasfrom the synthetic collection bag, resulting in unreliable findings. In theory,the analysis and results would be comparable to that of a stainless steel evac-uated air canister if the sample collection does not result in losses.

A chemically nonreactive, sample bag (0.5 to 120 liters) is installed andsealed within an airtight container that is larger than the fully inflated sam-pling bag and has chemically nonreactive, valve-fitted inlet and outlet ports.Where the inlet is connected to the sample bag the outlet is connected toa vacuum pump. As the vacuum pump draws a vacuum inside the sealed


container, the sample bag draws in ambient air to replace the void that iscreated inside the sealed container. In this manner, the collected air does notpass through a previously contaminated sampling pump, and the limitedcontact with various surfaces (to which chemical may adhere) that mightresult the loss of chemicals from the air being sampled. For an example of acommercially available “integrated bag sampler,” see Figure 8.8. Should youchoose to forgo the expense of a commercial unit, many environmental pro-fessionals build their own homegrown variety with Teflon connectors sealedto the interior of airtight plastic container (e.g., a Tupperware container ortrash can).6

The sample duration may theoretically be controlled by the flow rate ofthe sampling pump, and upon completion the bag valve stem is closed. Thecontainer seal is broken, and the sample is removed/prepared for shipping.Be sure to record all sampling conditions (e.g., sample name or number, tem-perature, humidity, and barometric pressure) and sample location(s) as pre-viously discussed, and ship the container to a laboratory. Some people whouse this system, however, have commented that time integrated sampling“never works out to fill the bag in the amount of time you think.”7

Shipping further poses problems that are unique to this method. Due tothe failed rigidity of the sampling bag an extreme change in atmosphericpressure (which does occur in air transportation) may result in an expansion

FIGURE 8.8VacBag sampler system. (Courtesy of Apex Instruments, Fuguay-Varina, North Carolina.)


of the bag to the point where its integrity is compromised (e.g., overfilled,damaged, or leaking). It is not unusual for sample bags to arrive at their des-tination with nothing inside. The way to avoid this problem is to collect onlyhalf the capacity of the bag, ship the bag in a rigid, pressurized container, orphysically transport the sample(s) on land to the laboratory.

Analytical Comparisons

In a comparison study three total VOC sampling and analytical methodswere performed in tandem at thirteen indoor locations.8 The methods wereTO-15 (i.e., canister collection) and two variations of TO-17 (i.e., single sorbentTenax® TA with thermal desorption and Radiello 145 with thermal desorp-tion), and the findings were sporadic. The canister total VOC concentrationswere two to three times greater than the other methods in two locations and10 percent to 25 percent greater than the others in two other locations. TheTenax concentrations were 10 percent to 25 percent greater than the canis-ters and double that of the Radiello in four locations. The remaining fivelocations were somewhat comparable with a 5 percent to 10 percent greaterconcentration favoring the Radiello. Half of these locations with canister andTenax dominating exceeded the 500 µg/m3 limit (as compared to toluene).Thus, there appears to be no consistent pattern between sampling meth-ods. The significance of these patterns is indeed elusive. See Table 8.3. Inconfusion, there may be some sanity in the results of the study! One maysafely conclude that each indoor air environment, each sample location has

TVO

C a

s Tol

uene

Con

cent

ratio

n, μ

g/m

31500

2000

1000

500

0

Radiello

Canister

Charcoal

Tenax

FIGURE 8.9Total VOC comparison of sampling methods.8 (Courtesy of Columbia Analytical Services,Kelso, Washington.)


different VOC components—different volatility and different polar proper-ties. Without knowing the components, it is difficult to draw a clear conclu-sion. The choice between canister and solid sorbent sampling for total VOCsappears to be irrelevant.

Yet Tenax is a single sorbent and performs well with higher boiling pointVOCs but does not capture the broad range of chemicals based on boilingpoint and molecular weight that a multiple solid sorbent captures. Thermaldesorbed solid sorbents yield light, medium, and high molecular weightcompounds with lower boiling points up to 250°C (e.g., components of low,moderate, and high volatility) and are not limited to the higher boilingpoints only. The comparison study did not include multiple solid sorbentwith thermal desorption. Therefore, it is likely that if included in the studysamples collected on Carbopak™, a multiple sorbent, and analyzed by TO-17,

TABLE 8.3

Characterization of Common Volatile Organics

Aromatic Hydrocarbons Chlorinated Hydrocarbonsbenzene methylene chloridetoluene 1,1,1-trichloroethaneo-, m-, p-xylene perchloroethylene (tetra-

Aliphatic Hydrocarbons chloroethane)n-pentane o-, p-dichlorobenzenesn-hexane 1,1,2-trichloro-1,2,2-trifloro-n-heptane ethane (Freon)n-octane Terpenesn-decane d-limonene

Ketones turpentine (pinenes)acetone Aldehydesbutanone (MEK) hexanalmethyl isobutyl ketone benzaldehydecyclohexanone noanal

Alcohols Acetatesmethanol ethyl acetateethanol butyl acetateisopropanol amyl acetatebutanol Other

Glycol Ethers Octamethylcyclotetrasioxanebutyl cellosolvediethylene glycol ethylether

Phenolicsphenolcresol2-, 3-, 4-methylphenol


the levels would have demonstrated greater total VOC concentrations in allsample locations in the study. Some laboratories indicate that clients who usethis method for total VOC screening frequently exceed the 500 mg/m3 limitas set forth by some environmental professionals. This is likely due to highmolecular weight, semivolatile organics (boiling point: 220–250°C) that areassociated with this method and excluded from others.9

As for component identification, EPA Method TO-17 is the best all aroundapproach for collection, analysis, and detection of a broad range of VOCs(C5–C17) with a boiling point up to 250°C. While it is one of the most expen-sive and unforgiving methods, TO-17 is the most powerful tool of identify-ing unknowns and the only method that includes 4-phenylcyclohexene inthe analysis.

EPA Method TO-15 (i.e., canister sampling) is a good all-around approachfor collection, analysis, and detection of a broad range of VOCs (C3–C12)with a boiling point up to 220°C. Although the cost for analysis is high, can-ister analysis is more forgiving than that of multibed thermal desorptionsampling should the laboratory misapply or lose your sample due to a glitchin the processing. Canister analyses can be reanalyzed; however, if there wasno duplicate, samples collected in accordance with TO-17 (i.e., multibed ther-mal desorption) will be lost and must be resampled. This is not the case withTO-15.

Also there are a significant number of lightweight VOCs in a building thatare normal to indoor air environments that the environmental professionalmay or may not want to identify. Only canister (and charcoal sorbent) samplingresults in the capture and analyses of lightweight VOCs. For example, acetonefrom fingernail polish remover and isopropyl alcohol in rubbing alcohol aretypically encountered in occupied spaces in relatively high concentrations. Ina total VOC screening the lightweight, normally present VOCs will likely con-tribute concentrations in excess of the 500 mg/m3 total VOC action limit.

Whereas TO-15 includes the highly volatile and moderately volatile VOCs,TO-17 includes moderately volatile and less volatile VOCs. To completelycover all bases wherein price is no object, component sampling and analysisby both EPA Methods TO-15 and TO-17 is recommended. This dynamic duocan be expensive, but the results are legally bulletproof.

Lastly, keep in mind that lower-level sulfur-containing and brominatedVOCs are not recoverable by either method unless a special silicon-coatedcanister is used for TO-15. When sulfur-containing mercaptans are suspect,the silicon-coated canister is superior to a canister that has not been coated.

Helpful Hints

VOC sampling is best performed in low-humidity environments. Althoughthe environmental professional rarely has a choice, remember to recordtemperature and relative humidity when taking air samples. Solid sorbentcapture of polar VOCs becomes compromised in high humidity as does


evacuated canisters, or whole air sampling, demonstrate difficulties duringthe analysis. The laboratory attempts to control the moisture with a purgeand trap system within the GC/MS, but extremely high humidity levels cannot be completely purged. Thus, high humidity may skew the results.

Each laboratory is different in capability, experience, equipment, andanalytical approach. The reference standards for total VOCs vary, and thedetection limits for components vary. The lists of VOCs with referencestandards vary, and the GC/MS library databases vary. All laboratoriesrequire preparation and precleaning/preconditioning of canisters prior tosampling, and most laboratories request multibed solid sorbent for ther-mal desorption be preconditioned, even if the sorbent has been newly pur-chased. Most laboratories provide the environmental professional withsampling supplies, and some are limited. To avoid confusion and question-able/undecipherable sample results, seek clarification from your laboratoryprior to sampling.

Upon VOC identification by GC/MS, sampling may be performed for theindividual chemicals at a considerably reduced cost. Further sampling mayprovide information regarding: (1) locations/areas impacted; (2) source track-ing; (3) HVAC contamination; and (4) individual exposures. As the methodsare highly variable, individual chemical sampling should be performed byan industrial hygienist trained in different sampling methods.

As of the writing of the book, there are several new products (e.g., deac-tivated glass bottles) on the market that allege great promise in the area ofVOC sampling. As they are not widely accepted and available through mostlaboratories, I have chosen not to elaborate.

In the preceding editions to this book, other sampling products were men-tioned as well. Due to their limited accessibility, obsolescence, and failedrecognition/use by environmental professionals/laboratories, some of thepreviously mentioned products (e.g., ambient air samplers and MSA evacu-ated cans) are no longer included in this book.


Where the total VOC screening is performed, the investigator decides onan acceptable/action limit, based on professional judgment. Professionaljudgment is based on experience and guidelines set forth by others as dis-cussed in previous sections. To recap the guidelines discussed in ScreeningProcedures, many investigators choose one of the following:

• A limit of 500 µg/m3, as compared to toluene, required for LEEDtotal VOC sampling

• A limit of 250 µg/m3, guideline of choice by a limited few whereodors are a main concern (due to the very low odor threshold levelsof many organic compounds, well below that which results in sys-temic complaints)


The investigator may choose a stricter limit or a less restrictive limit. Onceagain, the total VOC screening procedures are not intended to regulate butto investigate. Screening is performed to establish a limit whereby furthersampling is indicated.

Where the airborne levels of total VOCs are less than the limit decided onby the investigator, no further sampling or analyses is indicated. If, however,the screening levels exceed the limits, sampling for component identifica-tion should be performed. Once identified, the VOCs may be assessed on thebasis of the identified components.

The acceptable/action limit for known chemicals in indoor air environ-ments must, once again, be based on professional judgment. The investigatormay choose to use any one of the following:

• The ACGIH occupational exposure guidelines for specific chemicals(not recommended for use where 24-hour exposures may occur)

• The NIOSH occupational exposure guidelines for specific chemicals(generally more stringent than the ACGIH guidelines and not rec-ommended for use where 24-hour exposures may occur)

• One-tenth of the ACGIIH guidelines for specific chemicals• Published sensory irritation levels for specific chemicals• The ASHRAE 189.1 limits for specific chemicals (limits set at twice

the California RELs from the Standard Method for the Testing andEvaluation of Volatile Organic Emissions from Indoor Sources UsingEnvironmental Chambers)10

Where limit(s) are exceeded, comparative samples become an importantpiece of the pie. These include the following:

• Compare problem and nonproblem samples (e.g., the source of thecomplaint may be isolated)

• Compare indoor and outside samples (e.g., the source of the offend-ing chemical(s) may be outdoors)

• Compare previously taken samples in the building when there were nocomplaints to those taken at the same location as previously taken inresponse to complaints that have since developed (e.g., the source of thecomplaint may be intermittent, associated with events or activities)

In brief, there are no regulatory limits for indoor air quality. AssessingVOCs is complex, and interpreting the results is even more difficult. Canthe identified VOC or combination of VOCs be the cause of the complaint(s),or are they coincidental? What furnishings or building products could emitthe identified VOCs? Is the source of the identified VOCs generalized or


isolated? Is the source the HVAC system or sewage gas leak? Is furthersampling indicated?

Summary

Volatile organic compounds are ubiquitous. They are outdoors in pristinerural environments, and they are indoors in occupied environments. VOCsin indoor air, however, are compounded by confinement and build-up of acomplex mixture of chemicals that ultimately contribute to poor outdoor airand occupant complaints.

Total VOC screening is recommended in cases where organic chemicalsare suspected of causing odor complaints of affecting the health of the build-ing occupants. If the total VOCs exceed a predetermined acceptable limits(e.g., 500 µg/m3), component identification is recommended.

One size does not fit all. The best methods for identification of all possiblecomponents in an indoor air quality study are EPA Method TO-15 and TO-17,which are also the most expensive methods. If finances allow, the two meth-ods performed simultaneously can be a powerful tool.

If the cause is found, source identification may require more in-depth inves-tigation and sampling. For further information, see Chapter 13, “ProductEmissions”; Chapter 16, “HVAC Systems”; Chapter 17, “Sewage Systems andSewer Gases”; and Chapter 19, “Green Buildings.”

References

1. Kennedy, Eugene, PhD, and Yvonne T.G. December 1993. Evaluation of Sampling and Analysis Methodology for the Determination of Selected Volatile Organic Compounds in Indoor Air. (Research document) NIOSH, Cincinnati, Ohio.

2. U.S. Environmental Protection Agency. Indoor Air Pollution: An Introduction for Health Professionals. EPA. Viewed on May 8, 2010, at http://epa.gov/iaq/pubs/hyguide.html

3. Grote, Ardith A. Screening Applications Using Thermal Desorption Techniques.Presented at the AIHC Exposition in Kansas City, Missouri, on May 23, 1995.NIOSH, Cincinnati, Ohio.

4. 3M Technical Staff. 2010. 3M Technical Data Bulletin—Organic Vapor Monitor Sampling and Analysis Guide. 3M Center, St. Paul, Minnesota, pp. 7–10.

5. Dupraz, Carol, Lisa Brosseau, et al. 1997. Odor Thresholds for Chemicals with Established Occupational Health Standards. Fairfax, Virginia: AIHA Press, p. 20.

6. Shirley A. Ness. 1991. Air Monitoring for Toxic Exposures: An Integrated Approach.New York: Van Nostrand Reinhold, p. 406.


7. Fortune, A. Dec. 16, 2010. Comment. Columbia Analytical Services.8. Fortune, A. Nov. 1, 2009. “Comparison of Sampling and Analytical Methods

for Total Volatile Organic Compounds (TVOC) in Green Buildings. Presentationfrom the Florida Brownfields Conference. Columbia Analytical Services.

9. P. Pope. Jan. 4, 2011. Comments. ALS/DataChem.10. Horton, M. PhD. February 2010. Standard Method for the Testing and Evaluation

of Volatile Organic Emissions from Indoor Sources Using Environmental Chambers.California Department of Public Health.

163

9MoldVolatileOrganicCompoundsandMoldDetection

The year 2000 started with a bang in that molds took center stage in the overallconsideration of indoor air quality concerns. Yet sampling methodologies areexpensive, difficult to interpret, and require long laboratory turnaround times.

There is controversy amongst the experienced environmental profession-als. One investigator condemns a building, requiring extensive remediationwith minimal sampling, while another investigator attempts to assess simi-lar scenarios by more extensive sampling and using more tools to gatheradditional information. One of these tools that is gaining in popularity is airsampling for mold volatile organic compounds.

Some investigators choose not to perform air sampling for the physicalpresence of molds in the air. Due to the lack of well-substantiated data andclear guidance for interpretation, many investigators simply inspect for evi-dence of molds. These inspections may be performed by means of visualobservations, moisture testing, or odor tracking.

The purpose of this chapter is to provide a few more tools and approachesthat the investigator may find useful under different circumstances. Some ofthese techniques may prove to be indispensable to some, spirit incantationsand ghost busting to others. They are mere tools, techniques that can be veryeffective if used properly.

Health Effects and Occurrences

Some researchers feel that mold volatile organic compounds (MVOCs) maycause health problems. Whereas the scientists tend to focus on sensory irri-tation similar to that of volatile organic compounds (VOCs), nonresearchinvestigators report a concern that the MVOC may cause headaches, eye andrespiratory tract irritation, and dizziness. Currently, there is no substanti-ated data that correlates MVOC exposure levels to speculated health effects.

Metabolic by-products of molds are referred to as MVOCs and consist pre-dominantly of alkanes, alcohols, and ketones. The specific compounds thathave been identified are dependent upon mold type (i.e., genus and species),food consumed, and environmental factors (e.g., moisture availability). At thepresent, researchers are scrambling to identify MVOCs common to all fungi

164 IndoorAirQuality:TheLatestSamplingofAnalyticalMethods

and to determine variances between genera and species. See Table 9.1 for a listof some of the more consistently reported organics that may be anticipatedwherever molds are encountered indoors. According to one laboratory that hasperformed more than 600 analyses for various clients, the most frequently iden-tified mold by-products are 3-methyl-l-butanol, 2-octen-l-ol, and 2-heptanone.1

Some researchers feel that MVOC sampling data may result in more reli-able mold information than viable air sampling. They state that in visuallymoldy interior environments, air sampling sometimes yields false negatives.These false negatives are often confirmed false where molds are found hid-den in the wall cavities, under sheet vinyl, and within hidden spaces (e.g.,behind sinks and cabinets). The hidden molds can be detected by odor andconfirmed by MVOC sampling.

It is unclear as to whether the MVOCs are clearly causing health prob-lems or whether the presence of MVOCs is merely an indicator. There havebeen no studies published that link the chemicals identified as MVOCs at the

TABLE 9.1

Listing of Mold Volatile Organic Compounds2–7

Compounds Characteristic Odor

1-Octen-3-ol2,4–7 musty, mushroom-like2-Methyl-1-butanol3,4,7

2-Methyl-2-butanol6,7

2-Methyl-1-propanol3,4

2-Octen-1-ol4,5,6 weedy2-Pentanol4–7

3-Methyl-1-butanol3,6, 7

3-Methyl-2-butanol4–7

3-Methylfuran3–7

3-Octanol2,4,5,6 nutty3-Octanone2,5–7 sweet ester, metallic-like1-Butanol4

Dimethyl sulfide3,4

Geosmin (terpene)3,4,5,7 earthy2-Heptanone4-7

2-Hexanone4-7

2-methyl-isoborneol5,6

2-isopropyl-3-methoxypyrazine5-7

1-Octanol7

1-Pentanol7

2-Pentylfuran7

Furan7

2-Butanone7

3-Methylfuran7

2-Ethyl-1-hexanol7

MoldVolatileOrganicCompoundsandMoldDetection 165

reported levels to be associated with health complaints. Reported levels havebeen around 50.5 µg/m3 total MVOCs, 16.1 µg/m3 2-octen-l-ol, and 1.8 µg/m3

methylfuran. There are no American Conference of Governmental IndustrialHygienists (ACGIH) limits for either 2-octenol or methylfuran, and they areconsidered slightly toxic and moderately toxic, respectively.8 The other com-pounds listed as MVOCs are slightly to moderately toxic.

On the other hand, however, investigators have used MVOC sampling notonly to locate but to rule out the presence of molds in wall spaces. In one case,a consultant recommended an entire residence be leveled to the ground. Thiswas based on known water damage, some visible molds, and minimal sam-pling. Another consultant investigated, drilled a small hole in each wall, tookmultiple samples, and isolated the problem area to a couple of walls. The endresult was remediation of a couple of walls and some wall sections. The occu-pants returned to the residence, and their health complaints did not recur.

Researchers are attempting to determine the efficacy of identifying moldgenus and species by MVOC fingerprinting. Although there has been someconsistency in results with distinct differences between species, most researchhas been performed under controlled laboratory conditions with well-definednutrient agars. Within the same species (e.g., Penicillium varotii), many of theMVOCs grown on malt extract agar are different from those grown on dichlo-ran glycerol agar. In a building, the nutrients are variable. There are likely tobe more than one type of mold contributing to the total indoor MVOC, andMVOCs that are detectable are typically lower than indoor background VOCs.Whereas the indoor VOCs associated with off-gassing of building materialsand furnishings may range from 200 ppb to 2 ppm, high levels of total MVOCsmay range from 0.01 µg/m3 to 2000 µg/m3, averaging around 33 µg/m3 (i.e.,8 ppb as compared with hexanone). For MVOC findings from compositesreported at a NIOSH conference in 1997, see Table 9.2.

TABLE 9.2

Microbial Volatile Organic Compound Database10

Location/Types of MVOC

Average Concentration

(11µg/M3)

# of Positive Sites of Total

Sites Sampled

Indoor air samplesTotal MVOC 50.5 106 of 1191-Octen-3-of 4.8 40 of 1192-Octen-1-of 16.1 58 of 1193-Methylfuran 1.8 4 of 119

Outdoor air samplesTotal MVOC 6.5 8 of 201-Octen-3-of 1.5 2 of 202-Octen-l-of 3 3 of 203-Methylfuran – 0 of 20


To further complicate matters, bacteria produce VOCs as well. Therehas been limited research regarding bacterial VOCs, yet bacteria can con-tribute to the MVOCs or be the primary contributor. Bacterial VOCs maypotentially muddy the waters when interpreting these common VOCs withthe assumption that they are clearly mold by-products. The predominantby-products produced by both bacteria and molds are 1-propanol, 2-butanol,and dimethyl trisulfide.11 It should also be noted that actinomycetes (e.g.,3-methyl-l-butanol, dimethyl trisulfide, and geosmin), algae, and trees (e.g.,terpenes) may produce similar VOCs as well.11,12

Sampling for MVOCs

Sampling for MVOCs is an evolving science. There is little or no publishedguidance available from government sources, and there are varying opinionsamongst laboratories. The information provided herein is the most recentinformation available prior to publication of this book. Locate a laboratoryand discuss their experience and capabilities for analyzing MVOCs. The pro-tocols will remain in flux until NIOSH or another government entity publishtheir own method.

Sampling Strategy

Careful consideration should be given to where sample data will providedata that the investigator can best interpret. Exposure sampling may beperformed in order to determine exposure levels and assess the MVOCimpact on occupant health. These samples should be taken within occu-pied areas.

Diagnostic sampling may be performed in order to locate areas in wallspaces where destructive sampling is not desired, and the investigator isattempting to locate where molds are actively growing. These samples shouldbe taken within the wall space(s) or other inaccessible areas.

Once the decision has been made as to whether to sample for occupantexposures or wall spaces, the investigator may wish to target sites that arelikely to represent worst case scenarios. This may be done through odortracking, comments from building occupants, or low-level VOC detectioninstrumentation (e.g., ppbRAE). The latter approach shows promise as ameans for tracking MVOCs to the source. The author’s experience has beenthat of tracking molds using a ppbRAE like a tracking device. As the sitewhere molds are growing is approached, the readings on the meter becomeelevated. Where background has typically been less than 300 ppb, VOC lev-els at identified moldy areas may exceed 1000 ppb, sometimes going as highas 20,000 ppb (or 20 ppm).


Comparative samples should also be taken with a minimum of oneoutside sample. If possible, an indoor noncomplaint or nonproblem areashould be sampled as well when performing occupied space sampling.This is particularly important where there are no guidelines for interpret-ing results.

Sampling Methodology

Air sampling for MVOCs has been and can be performed by the same meth-odologies as those used for VOC. More recently, however, specific moldorganic by-products have been targeted, and an MVOC method developed forthose organics that have been commonly encountered in various studies.

Although the specific MVOCs that are targeted may very by laboratory, theend result is exclusioin of the VOCs associated only with building materials,

FIGURE 9.1Non-penetrating Moisture Meter (left) and Penetrating Moisture Meter (right)


furnishings, and activities. Otherwise, you may not “see the forest throughthe trees.” The MVOC target compound sampling technique is more focusedthan the broad VOC methods and easier to interpret.

The method requires the following:5,13

• Air sampling pump—low flow• Capture medium: SKC Anasorb® 747 or comparable solid sorbent

(e.g., AS002)• Warning: solid sorbent sampling media may be compromised by

high concentrations of ammonia, mineral acids, and high humidity(e.g., greater than 90% RH)

• Flow rate: 0.5–0.2 liters per minute• Range air volume: 40–120 liters• Desorbtion: dichloromethane• Standard: target compounds• Analysis: GC-MS• Limit of detection (per compound): 0.1–0.5 μg/L mL injected

dichlormethane• Special handling: laboratory dependent (some require refrigeration and

shipping in a cooler with Coolpak while specify “do not refrigerate”)

Samples may be taken from the occupied air within a building or fromwithin a wall space/area suspect of having MVOCs.

Screening Methodologies

A building inspection for molds is one of many diagnostic tools that maybe used for assessing a building for potential mold growth. They go outside“sampling” envelope and enter into other disciplines (e.g., building construc-tion technology). At the same time, these techniques support each other andare most effectively simultaneously. The investigator should be open to allpossibilities.

Visual Observations

As discussed in previous chapters, molds have known, predictable habitsand habitats. They thrive in high moisture. They require organic material fornutrition, and they do not require light.

Most molds require in excess of 80 percent moisture on or in a food sub-strate. See Tables 5.3 and 5.4 for moisture requirements of some molds. In


buildings, the food substrate may include but is not be limited to wet gyp-sum board paper, damp carpeting, wet wood flooring and trim, damp uphol-stery, moist areas under vinyl wallpaper and floor tiles, wet ceiling tiles, andevaporation in duct insulation.

Moisture may be due to a plumbing pipe/fixture leak, sewage leak, build-ing structural leaks (i.e., window jams, doors, and roofs), moisture buildupfrom uncured concrete foundation, moisture infusion due to temperaturedifferentials in a building, and condensation in the air handling system.

Plumbing leaks are the easiest, most commonly identified source ofmoisture buildup. The most common areas are under kitchen and bath-room sinks, and in and behind cabinets. The more difficult plumbing leaksto detect are those around bathtubs and toilets. Second story leaks tendto show wherein water stains become evident or water comes out fromaround wall penetrations (e.g., air supply louvers and lights). Even moredifficult to locate are damaged pipes in wall spaces. Moisture buildupinside a wall that has vinyl wallpaper can be difficult to locate as well. Yetthe glue for most wallpaper is water-soluble, and moisture buildup willloosen surface adhesion, making the wallpaper easy to lift. If there is nowallpaper, a water spot may or may not appear, depending on the extentof the leak.

Water and sewage leaks may occur around toilets or kitchen disposal unitsor a cracked concrete slab. Foundation shifts provide a conduit for brokensewage pipe moisture and gases to return to the interior air spaces.

Improperly sealed door and window jambs are typically a means wherebymoisture may enter the indoor air spaces, particularly where there is con-siderable moisture (e.g., excessive rain). Extreme temperature differencesbetween the indoor air and outside air (or indoor air and ground) may resultin moisture intrusion.

Roof leaks are a common source of moisture intrusion as well. These area little more difficult to track. Even if there are water stains on a ceiling,the actual site of a leak may not be easily traced due to extensive migrationwithin the roof space(s).

Concrete foundations require 28 days to cure, but many contractors do notallow more than a couple days for curing. Moisture is created in the cur-ing process, and when resilient floor tiles or vinyl sheeting are laid over theuncured surface, moisture becomes trapped and accumulates. It should alsobe noted that the old asbestos floor tiles permitted moisture to escape, andthe tiles were typically laid down with a solvent-based glue. The nonasbes-tos tiles trap the moisture, and these tiles are typically laid down with awater-based glue. When the water-based glues get wet, the glue begins tofail and the tiles begin to lift. Commercial carpeting may also have been putdown with water-based glues. Thus poor adhesion of floor surface materialsis a good indicator of potential moisture buildup.

Condensation in a commercial air handling system and window air condi-tioners occurs at the cooling coils. In large commercial units, the condensate


is collected in a drip pan where it should drain out of the unit. Often theunit fails to drain the full amount of settled water. Sometimes the drain getsplugged. This condensate buildup in the drip pan is a frequent source ofmoisture for molds to grow. Yet it does not stop here.

The moisture from the coils and drip pan is blown onto the surfaceimmediately after the cooling coils. This surface may or may not be insu-lated. The author has observed molds growing on what would otherwiseappear to be a clean metal surface. More frequently, however, this areaimmediately after the cooling coils is covered with impregnated fiberglassinsulation. A feltlike surface covering may be observed that may later beconfirmed as mold.

Poorly insulated duct or noninsulated spots in walls may also be a source forcondensation buildup, especially where the temperature difference is extremebetween the air in the ducting and outside in an attic space. The conditionof the duct and insulation may be observed, and moisture buildup can beobserved. Sometimes condensation occurs at the air supply registers. Moldsmay be observed growing on the outer edge of the louvers or just inside.

The nutritional source may be glue, paper, decayed organic matter, organicdebris, soil, and human food. Many of these materials are found in housedust that can be found in all areas mentioned above.

Odor Tracking

Odor thresholds for some of those by-products produced by molds are quitelow. For instance, the odor threshold for dimethyl trisulfide has been reportedas low as 10 ppt. For 1,5-octadien-3-ol, the threshold has been published aslow as 1 ppt, and geosmin is noticed at 5 ppt.14,15 For comparison, the verydistinct odor for hydrogen sulfide is noticeable for many at 4.5 ppb, and fora limited number of people, the rotten egg odor is sometimes identified atlevels as low as 70 ppt.

Note that there are no ACGIH or Environmental Protection Agency (EPA)standards for dimethyl trisulfide, 1,5-octadien3-ol, or geosmin, whereas theACGIH TLV-TWA for hydrogen sulfide is 5 ppm. Thus in the case of MVOCs,odor should not be mistaken as an indication of excessively high levels ofMVOCs or health effects.

To overstate the obvious, some people have a greater sense of smell thanothers. Those of such great fortune (or misfortune) who are able to trackodors may go to the source. Sometimes building occupants can direct theinvestigator to a source.

Odors are typically associated with visually observed molds out in clearview, but sometimes odors can be isolated and molds located behind or inhidden spaces. These hidden spaces may include but are not be limited towall spaces (e.g., behind light sockets), around windows, areas under carpet-ing, behind bathroom sinks, and ceiling spaces.


One drawback to tracking odors is that by the time a moldy odor isnoticed, the odor has diffused into the general air space or been mixed withthe air from within the air handling unit. For this reason, if the source is themechanical air ducts, interpretation can be particularly difficult. Odor alonewill rarely isolate the problem. Other methods must be used.

Moisture Testing

Where moisture cannot be observed and is suspect, a moisture detector isquite useful. Without a moisture meter, an investigator may overlook poten-tial areas for mold growth, or suspect areas must be demolished. The laterculminates in poor aesthetics, potential release of enclosed mold spores, andexpensive repairs.

A moisture meter detects moisture through paint, varnish, wallpaper, floortiles, wood, and carpeting. There are two types of meters. Each is useful ina different way. The nonpenetrating moisture meter (e.g., Tramex® MoistureEncounter) is nondestructive, and the penetrating meter (e.g., DelmhorstBD-21) has prongs that must penetrate in to the substrate leaving small holeswhere the substrate was tested.

It should be noted that metal will also defect the meter. If the materialbeing tested has metal composition or structural steel behind the surface, themeter will read high moisture content. Some gypsum board has an alumi-num foil backing to provide thermal insulation where the gypsum board isused along exterior walls. The aluminum foil will deflect the meter full-scale,result in erroneous readings regarding moisture content.

The non-penetrating moisture meter has three scales that are based ondepth of reading and sensitivity, and it has two ranges. The relative range isthat used most frequently, and the percent wood range is for wood only.

• Scale 1, the wood setting, is used to measure from the surface down ½to ¾ inch deep, and the reading is in percent water. Dry wood shouldread less than 12 percent on the % H2O Wood indicator range. Donot expect treated lumber to be dry. The treatment process is a wetprocess and prevents fungal growth.

• Scale 2, the drywall setting, is used to measure from the surfacedown to 1 inch deep, and readings are in relative moisture con-tent. At the setting, the meter may be used to penetrate carpeting,floor tiles, and roofing shingles. Scale 2 may be used to encountermoisture in a second layer of drywall. A fire wall will generallyhave two layers of drywall. It may be used to encounter moisturetrapped below floor tiles. If there is wood flooring, Scale 2 can pene-trate the surface sufficiently to determine moisture that lies beneaththe wood.

• Scale 3, the plaster/brick setting, measures from the surface down¼ to ½ inch deep, and readings are in relative moisture content. Yet


Scale 3 may be used to check depth of moisture the drywall. If thereis little or no reading at ¼ to ½ inch depth, a reading on Scale 2is likely to indicate most of the moisture is deeper. If, however, theScale 3 reading is higher than the Scale 2 reading, the moisture islikely to be closer to or on the surface. For instance, moisture maybe trapped behind vinyl wallpaper or there may be condensation onthe surface.

A penetrating moisture meter is slightly more complicated. One cannot com-pare penetrating meter reading to nonpenetrating readings. This would be liketrying to compare apples to chocolate. Both are good, but they are different!

The penetrating moisture meter reading resistance between two probesthat must penetrate the surface of the substrate to get a reading, and themeter only provide moisture content information between the two probes.Most penetrating moisture meters come with ¼ inch probes. This means thatif there is moisture at a depth greater than ¼ inch, there will be little or noreading. Yet there is a way around this minor problem. Extension probes upto 3 inches in length can be attached to the meter, extending the measur-ing depth considerably. Well, now, we have another problem. The surface ofmost materials (unless drywall is overly wet) is too hard to penetrate withoutpredrilling a couple holes. Whereas the smaller probe leaves small holes, thelarger probe generally leaves unsightly ¼ inch holes.

There are also three scales for the penetrating moisture meter, and all thereadings are in moisture content, not relative moisture.

• Scale 1, the wood setting, is similar to that of the nonpenetratingmoisture meter. In both, red line and buzzer indicate percent mois-ture content in excess of 17. The probe, once again, only reads as deepas the probe will go, whereas the nonpenetrating goes down as far as¾ inch.

• Scale 2, the plaster/concrete setting, will red line and buzz at 95 per-cent moisture content. The red line for plaster on the nonpenetratingis 70 percent relative moisture.

• Scale 3, the drywall setting, will red line and buzz when its readingis greater than 1 percent moisture content. The red line for drywallon the nonpenetrating is 70 percent relative moisture.

The nonpenetrating moisture meter is easier to use and does not turn thewall into a pin cushion. A penetrating meter can be used to test the surfaceof a substrate without penetrating. Given this approach, the investigator candetermine whether there is surface moisture. Otherwise, when the depth ofthe moisture is required or where a depth greater than 1 inch is required, thepenetrating meter shines. Both tools used wisely can provide informationthat would otherwise be incomplete.



When assessing occupied space MVOCs, indoor sample results should becompared to outside samples. Short of concluding that the results outside area given multiple of that indoors, identified MVOCs that have exposure lim-its may be compared wit other standards in a similar fashion to that of thatof VOCs. It is highly unlikely, however, that any known standards will beexceeded. Otherwise, the investigator should seek the assistance of someonewith more experience, expertise.

One laboratory that has considerable experience with MVOC analysis haspublished interpretation tables. If a comparison outdoor has not been taken,the laboratory suggests adding all the identified MVOC results and refer toa table which is based on “experience gained . . . through interactions withmany professionals who are active in mold sampling and remediation.” SeeTable 9.3.

When assessing wall space MVOCs, in-wall sample results should be com-pared to outside samples and possibly samples obtained from wall spacesknown not to have or to be associated with mold growth. Sample resultswill, once again, be relative to known non-problem areas. In this instance,interpretive tables are not likely to be appropriate. Comparison samples area must!

Positive findings upon the visual observation of what appears to be moldshould be confirmed. That which appears to be mold is not always mold. Forinstance, one building owner was prepared to close down a restaurant andspend large sums of money on remediating a black velvet-looking spot inthe kitchen area. Confirmatory sampling disclosed that the mold was indeedgrease with carbon particles from cooking.

TABLE 9.3

MVOC Interpretation in Occupied Indoor Spaces (Where No Outdoor ComparisonSamples Were Taken)

Sum (ng/L) Level Explanation

<8 Minimal Actively growing molds may be present but are at or belowlevels found in most homes of working environments.

30–Aug Low Actively growing molds are present but at levels which,generally, may only affect people very sensitive to molds.

30–150 Moderate Actively growing molds are present, significant allegicreactions are possible.

140–300 Heavy Very significant levels of actively growing molds are present,significant allergic reactions are very probable.

>300 Severe Very high levels of actively growing molds are present,immediate action should be taken.


On the other hand, negative visual observations do not necessarily meanthere are no molds. Moldy, earthy, musty odors may be traced to enclosed,hidden areas, and a moisture meter may identify high moisture areas. Bothscenarious are likely to be associated with molds. In these cases, furtherinvestigation by demolition, surface sampling, and/or mold air sampling isindicated.

Even when MVOC sampling and a building inspection fail to identify anyobservable molds or molds that can be found through demolition, air sam-pling may still indicate a problem. Then, the onus comes back to the inspec-tor. The search is afoot!

Summary

MVOC sampling and building inspections have been added to the investiga-tor’s bag of tricks. MVOC sampling is best utilized to locate mold growth inhidden spaces. Visual observations can be very effective in identifying probablesources of mold growth, and the more knowledge an investigator has regardingbuilding construction technology, the more effective a building investigation.

Characteristic mold odors and MVOCs may be traced to a source or site(s)where there is potential mold growth. A moisture meter may be used tolocate moisture, growth havens for molds. The combined approach for iden-tifying growth sites can be highly effective. Yet a visual inspection of suspectareas may be required for confirmation.

References

1. Air Quality Services. Using Microbial Volatile Organic Compound Analysis toDetect Mold in Buildings. AirfAQS Extra. 5(3).

2. Burge, H.A. Bioaerosols. CRC Press, Boca Raton, Florida. (1995), p. 258.3. Sunesson, A.-L., et al. Identification of Volatile Metabolites from Five Fungal

Species Cultivated on Two Media. Applied and Environmental Microbiol ogy.61(8):2911–18 (1995).

4. Wessen, B., and K. Schoeps. Microbial Volatile Organic Compounds—WhatSubstances Can Be Found in Sick Buildings? Analyst. 121:1203–05 (1996).

5. ACGIH. Bioaerosols: Assessment and Control. ACGIH, Cincinnati, Ohio (1999).pp. 26–1.

6. Aerotech Labs. IAQ Tech Tip #42: MVOCs. http://www.aerotechlabs.com(October 2000).

7. PATI. MoldScan.TM Application Note 523 rev. 1. Prism Analytical Technologies,Inc., Mt. Pleasant, Michigan. (2010).


8. Lewis, R.J. Sax’s Dangerous Properties of Industrial Materials, 10th ed. John Wiley& Sons, Inc. New York (2000).

9. Air Quality Services. Using Microbial Volatile Organic Compound Analysis toDetect Mold in Buildings. AirfAQS Extra. 5(3).

10. Moray, P., A. Worthan, et al. Microbial VOCs in Moisture Damaged Buildings.Healthy Buildings lIAQ 97. Conference Venue. Natcher Conference Center atNational Institutes of Health, Bethesda, Maryland. 1:247 (September 27–October2, 1997).

11. Burge, H.A. Bioaerosols. CRC Press, Boca Raton, Florida (1995), p. 260.12. Ibid., pp. 250, 258.13. PATI. Instructions for Jaking in Samples Using As002 Tubes. Technical Bulletin

502 rev. 9. Prism Analytical Technologies, Inc., Mt. Pleasant, Michigan. (2010).14. Ibid., p. 251.15. Pengfei, G. MVOCs. E-mail from Centers for Disease Control (September 28,

2000).16. PATI. How to interpret MoldScan results. Technical Bulletin 525 Rev 2. Prism

Analytical Technologies, Inc., Mt. Pleasant, Michigan. (2010).

177

10CarbonDioxide

An angry complaint is lodged, “There is no oxygen in the room. Everyoneis passing out!” The comment comes from an office occupant in a buildingwhere this health complaint is unique. The occupant had previously com-plained about the cold air supplied in her office space. Subsequently, her airsupply was turned off, and when accommodating visitors, she closed thedoor to her already stuffy office. The predictable results were elevated levelsof carbon dioxide in a confined space.

Ever-present in our outdoor environment, carbon dioxide levels are nor-mally higher indoors than outside. The elevated levels indoors may be due tocombustion, leaking compressed gases, and animal respiratory by-products.In indoor air quality, carbon dioxide is primarily an indicator gas. It is anindicator of inadequate fresh air or insufficient dilution of air contaminantsgenerated in a building.

The source of complaints may be formaldehyde off-gassing from furniture,but the elevated levels of formaldehyde may be alleviated with an increase infresh air entering the building. The carbon dioxide levels provide informa-tion as to the adequacy of fresh air supplied to the occupied spaces. This isthe first consideration in rectifying an indoor air quality concern.

Occasionally, however, carbon dioxide contributes to health complaints ina subtle fashion. In some cases, indoor air quality investigations have beenassociated elevated carbon dioxide levels with complaints of stuffiness andinadequate air. The sense of inadequate fresh air may be voiced in terms of“can’t breathe” or a “stuffy, suffocating sensation.”

Rarely are the carbon dioxide levels excessive to the point of causing a sig-nificant impact on human health. At levels well in excess of those normallyfound in indoor air quality studies, carbon dioxide is a simple asphyxiant.When levels approach percent of total air, carbon dioxide begins to displacethe much-needed oxygen. The most sensitive sign of reduced oxygen in thebreathing air is a reduced ability to detect slight differences in the brightnessof objects. As the levels increase, the symptoms progress from an increasein heart or respiratory rate to headache and a feeling of fatigue. In extremeintoxication, exposed individuals may experience nausea and vomiting, pro-gressing to collapse and unconsciousness.

As an indicator, carbon dioxide levels are used predominantly to deter-mine adequacy of the air exchange and to isolate stagnant air pockets wherethere is little or no air movement. Although the air exchange in an officebuilding may be adequate, areas may not receive their share of supplied air.


For those rare occasions whereby carbon dioxide levels may become exces-sive, the investigator should be aware of the potential sources. The assess-ment of carbon dioxide levels is a basic tool to be utilized in all indoor airquality investigations.

Occurrence of Carbon Dioxide

Carbon dioxide is a colorless, odorless gas. When mixed with water, it isreferred to as carbonic acid that has a slightly acid taste.

Humans and other animals inhale oxygen and expel carbon dioxide as awaste product. Plants inhale carbon dioxide and expel oxygen. AccordingCharles Keeling, ambient carbon dioxide levels shift hourly, daily, andannually. In the afternoon, levels have been recorded as low as 0.031 percent(i.e., 310 ppm). Annual measurements taken at Mauna Loa Observatory inHawaii (the site of a volcano that erupted as recently as 1984) have recentlybeen recorded, on the island, at 0.0385 percent (i.e., 385 ppm). There areslight variations in these levels, depending on location (e.g., rural farmland),the time of year (e.g., plant uptake of carbon dioxide occurs during growingseason in the summer), weather (e.g., air inversions may trap and result inan increase of all air pollutants), and industrial exhaust (e.g., combustionby-products).

In indoor air quality, the primary source of carbon dioxide is humanexpelled air. The expelled air builds up in airtight buildings, confined airspaces (e.g., enclosed offices with no air supply), overcrowded spaces (e.g.,classrooms), and high activity areas (e.g., health clubs). Thus indoor carbondioxide levels are usually greater inside a building than outside, even inbuildings with no health complaints.

Typically, at the start of an office day, the carbon dioxide levels will bearound that of outside air (e.g., 400 ppm). As the occupancy increases withtime, so do the carbon dioxide levels. The levels increase and decreasewith the fluctuations in occupancy. In an office building, the peak carbondioxide levels tend to occur in mid-afternoon at about 1000 ppm. Wherethere is adequate outside fresh air exchange, the peak may be as low as800 ppm. Where it is inadequate or nonexistent, the levels may exceed1000 ppm.

Other sources of carbon dioxide are by-products of combustion (e.g., automo-tive traffic), sugar fermentation, ammonia production, carbonated beverages,compressed carbon dioxide (e.g., fire extinguishers), dry ice, and aerosol propel-lants. Common indoor sources may also be gas cooking appliances, space heat-ers, wood-burning appliances, and tobacco smoke. Industrial exhausts wherebyburning is involved (e.g., sanitary waste) should not be ruled out. All potentialoutside contributors to the total carbon dioxide levels should be investigated.

CarbonDioxide 179

Outside the building contributors to the total indoor carbon dioxide levels shouldbe assessed—at the HVAC air intake for the building or other areas where theoutside air might conceivably enter the building (e.g., frequently used doors andcarbon dioxide in the proximity of the doors).

A carbon dioxide level in excess of 1000 ppm should be considered an indi-cator of inadequate makeup air in a building. The recommended limit to min-imize health effects according to the American Conference of GovernmentalIndustrial Hygienists (ACGIH) is 5000 ppm.

Sampling Strategy

In offices and conditioned school buildings, the investigator should performair monitoring for carbon dioxide to assess the adequacy of the makeup air.As carbon dioxide levels change over time with occupancy rates, the inves-tigator needs to be aware of the time of day when samples are collected. Inareas where the occupancy and activities are not consistent, the carbon diox-ide levels will fluctuate accordingly.

Consider the conditions, and determine sample locations accordingly. Con-ditions to be considered should include, but not be limited to, the following:

• Different air handling zones• Worst case complaint areas• Noncomplaint areas• Heavily occupied areas during peak occupancy periods• Enclosed office spaces (air supply open or close)• Center of cubicle areas• Occupied and nonoccupied spaces• Different activity areas• Time of day and occupancy

In areas where the occupancy and activities are not consistent, the carbondioxide levels will fluctuate. In an ideal world, the investigator should takethree samples at each location. These samples should be taken at occu-pancy startup, mid-day, and mid-afternoon (e.g., 9 a.m., 12 p.m., and 3 p.m.).Wherever feasible, a data logging monitor may alternatively be placed in oneor two of the more strategic locations for 8- or 24-hour monitoring.

In some instances, the investigator may not have the benefit of an all-dayevaluation. If limited in time, attempt to assess areas around times when lev-els would reasonably be expected to be at their highest (e.g., mid-afternoonin an office building).


The investigator may choose to take numerous samples and contour anarea. This can be informative while providing an easy to review visual ofrecorded numbers and relative references. The number of samples collected,however, may be limited by sampling methodology.

Sampling Methodologies

Air sampling may be performed by direct reading instrument, colorimet-ric detector reading, or evacuated air collection. Whereas a direct readinginstrument and colorimetric detection provide instantaneous data, collect-ing a sample requires laboratory analysis. The approach to each of thesemethods is discussed herein.

Direct Reading Instrumentation

If a large number of data points are required and the equipment is readilyavailable, direct reading instrumentation is the most feasible approach tocarbon dioxide monitoring. Equipment may be purchased or rented.

Carbon dioxide monitoring will generally be part of an indoor air qual-ity monitor that provides continuous real-time data on four parameters—temperature, relative humidity, carbon monoxide, and carbon dioxide.Many of these instruments also record and store the parameters. Theyallow for long-term monitoring in order to track changes in carbon diox-ide levels throughout the day or even for a 24-hour time period. SeeFigure 10.1.

Colorimetric Detectors

If a small number of data points are to be collected and direct reading equip-ment is not readily available, colorimetric detection is the most feasibleapproach. The initial purchase of a pump and detector tubes is relatively lowin cost, and equipment is easy to carry. However, when the sample numbersexceed 10, the cost of the tubes starts to outweigh the cost of direct readingequipment rental.

The term “detector” is an operative term in that colorimetric detectorsdetect levels instead of providing precise data. Yet they are simple, easy touse, and practical for spot checks and collecting limited samples when directreading instrumentation is not available.

Colorimetric detection of chemicals is vintage science that has been avail-able for more than 50 years. Detection is based on a chemical reaction betweenthe specially prepared sample tube and the gas or vapor.

CarbonDioxide 181

Sampling equipment includes a hand held bellows or piston pump and detec-tor tubes, specific for the chemical in question (e.g., carbon dioxide). The pumpand tubes must be from the same manufacturer. Do not mix products (e.g., aDrager tube with an MSA pump). The tubes are chemical specific with differentranges (e.g., 0.01 percent to 0.3 percent by volume, which is 100 to 3000 ppm).

The detection methods have a manufacturer rated accuracy of 15 percent to25 percent, depending on the manufacturer. Some experienced investigators,however, have found variances in the low range that depart from direct readinginstrument data taken at the same location by as much as 50 percent.

When the components within the tube react with the gas or vapor beingsampled, there is a color change (e.g., white to violet). The tube is marked withgeneralized detection levels, and the length of the color change provides infor-mation regarding the detection level at that point in time. See Figure 10.2.

FIGURE 10.1Indoor air quality monitor—KD AirBoxx Monitor (Courtesy of KD Engineering in Bellingham,Washington).


Determine potential interferences or cross-sensitivities. There are no cross-sensitivities listed for Drager® carbon dioxide detector tubes.

The sampling method is summarized as follows:

• Equipment: bellows or piston pump• Sampling medium: carbon dioxide detector tubes in desired range• Procedure: insert tube in pump holder with arrow pointing toward

the pump, squeeze and release the pump for the number of strokesdesigned by the manufacturer (1 to 10 times), allowing the pumpbellows or piston to fill completely between each stroke

• Analysis: read the concentration on the basis of the perceived lengthof the color change

Helpful Hints

Take prolific notes, and record sample locations on a building schematic. Thebest reference is a visual of instantaneous or long-term averaged data. If it isnot possible to record the sample locations on a schematic, record the precisesample location and rationale for sampling at that location (e.g., no air move-ment). Always record the time each data point was collected.

FIGURE 10.2Drager colorimetric detector kit with carbon dioxide sample tubes.

CarbonDioxide 183

Don’t hold or place the monitoring probe or sample inlet close to your face.Breathing into the monitor will result in unreasonably elevated data. Theplacement of a monitor for long-term data logging should also be so placedas to avoid other people from breathing directly into the monitor probe.Upon final analysis, however, a well-planned sample site may culminate in afew surprises (e.g., a small mid-day meeting of people around the vicinity ofthe monitor). Attempt to keep track of activities, and never assume an unat-tended monitor will remain untouched.


Properly ventilated buildings should have carbon dioxide levels between 600and 1000 ppm with a floor or building average of 800 ppm or less.1 The 1000ppm should be used as a guideline only. It is not a strict, not to be exceededlimit. It is only a guide or indicator to adequate fresh air.

Assess the results in terms of occupancy, location, and time of day. Onearea may exceed 1200 ppm while other areas average below 800 ppm. Thereis a reason for this discrepancy. It deserves further investigation. Do notdamn the entire building for the sins of one area! The cause of a single dis-crepancy may be insufficient or no air supply to an area, or it may be due tounusually high traffic on the day of the monitoring (e.g., large meeting in asmall conference room).

If all areas average above 1000 ppm, however, and the outside air is lessthan 400 ppm, the environmental professional should suspect insufficientoutside air. Insufficient outside air means the indoor air contaminants arelikely to be entrained within the HVAC system. Product/building materialemissions and other building activity contaminants will build up over timeand contribute to poor indoor air quality. Thus elevated carbon dioxide lev-els may serve as an indicator or early warning sign of contaminant buildupwithin the occupied area(s).

On the other hand, if the carbon dioxide levels are extreme and the makeupair supplied to the building is open (and confirmed to be adequately open),contaminant buildup may be a red herring. The source of the problem maybe outdoors.

Where the levels exceed the ACGIH recommended limit of 5000 ppmand the outside air is less than 400 ppm, seek other sources besides humanexhaled carbon dioxide inside the building. It may be coming from by-products of combustion from within, and they may yet to be identified.Otherwise, exceeding the limit of 5000 ppm is likely to be associated withoutside sources (e.g., industrial exhausts).


Summary

Carbon dioxide monitoring is primarily a diagnostic approach for determin-ing the adequacy of the fresh air supplied to a building or occupied space.The source of elevated carbon dioxide levels is generally, but not always, anormal human by-product. Other sources are possible, and limits are notprecisely defined. Be open to all possibilities!

185

11CarbonMonoxide

According to the American Medical Association, 1500 people die annuallydue to accidental carbon monoxide exposures. More than 10,000 people seekmedical attention, and there are infinitely more who experience the nonlethalhealth effects and fail to report their mishaps. Medical experts speculatedthe reason for underreporting is that the symptoms of carbon monoxide poi-soning resemble other common ailments and are not recognized as carbonmonoxide poisoning.

Carbon monoxide displaces oxygen in the oxygen-to-blood transfer in thelungs. It has an affinity for the oxygen-carrying sites on the hemoglobin inthe blood of 210 to 240 times greater than oxygen. As it displaces the oxygen,carbon monoxide prevents the distribution of the needed oxygen. The tissuesbecome oxygen starved, and the individual fails to receive adequate oxygensupply. The higher the carbon monoxide levels, the greater displacement ofoxygen occurs, and the more oxygen deficient the individual becomes.

Initial symptoms may be mistaken for the common flu or a cold. Thisincludes shortness of breath on mild exertion, mild headaches, listlessness,and nausea. As exposures increase, the individual may experience severeheadaches, mental confusion, dizziness, nausea, rapid breathing, and faint-ing on mild exertion. In extreme cases, not normally encountered in indoorair quality situations, exposures may result in unconsciousness and death.1

In indoor air quality, the initial symptoms of carbon monoxide poisoningmay be difficult to differentiate from other causes of health complaints. Afterdetermining the occupants have symptoms that may indicate carbon mon-oxide poisoning, the investigator should be prepared to identify potentialsources and perform air monitoring.

Occurrence of Carbon Monoxide

Carbon monoxide is a colorless, odorless gas. It is a flammable, combustionby-product, an important contributor to heat production. Carbon monox-ide provides more than two-thirds the heat value created by carbon-based,combustible materials. In oxygen-rich air, carbon monoxide burns to formcarbon dioxide. When there is insufficient oxygen, however, carbon mon-oxide does not burn completely and becomes one of the many by-productsof combustion.


Incomplete combustion by-products of carbon-based fuels consist ofother contaminants as well. These products often have a color (e.g., rednitrogen dioxide gas) or an odor (e.g., aldehydes and volatile organic com-pounds). Although carbon monoxide is colorless and odorless, other com-bustion by-products may be detected. If one complains of gasoline odors,the presence of volatile organic compounds should set off alarm bells tothe investigator.

Combustible carbon-based materials include wood, charcoal, coal, naturalgas, gasoline, diesel fuel, kerosene, oil, organic waste, and tobacco products.Materials less commonly implicated in indoor air quality studies are build-ing, automotive, furniture, interior, and decorative materials involved infires. Although rare, the latter scenario involving fire damage in or aroundthe complaint area should not be overlooked.

In most instances, sources of elevated levels of carbon monoxide and othercombustion by-products are encountered in one, or a combination of, the fol-lowing scenarios:

• Vehicle exhaust in a building (e.g., air intake to a building located atstreet level in a busy alley or an automobile left running in a garage)

• Poorly vented gas-fired hot water heaters• Air from a leaking exhaust duct or furnace flue• Combustion by-products vented close to an air intake for a building• Poorly sealed wood-burning stoves• An insufficient amount of oxygen supplied to a gas-operated

space heater• Poorly tuned forklift trucks• Poorly vented and insufficient replacement air in a building with

natural gas and wood burning fireplaces (e.g., tight buildings withlittle or no air coming from outside to replace the air dischargedthrough the chimney)

• Gas-fired heaters in air handling units• Industrial combustion gases from an associated building

Exposures may be the result of a complex mixture of multiple sources.Individuals may be exposed at work and in their automobile that has a leakymuffler with the exhaust entering the interior of the car. Cigarette smokersare exposed to carbon monoxide when smoking tobacco products. Activitiesoutside the building or in a separate area of the same building may contrib-ute to carbon monoxide levels in the area under investigation.

Time of exposure can be elusive! Carbon monoxide levels in the bloodhemoglobin have a three- to five-hour half life. This means it takes up to fivehours for half of the carbon monoxide tying up the oxygen receptor sites in

CarbonMonoxide 187

the blood to dissipate. In other words, when an individual departs an areawhere he/she is exposed to a carbon monoxide generating activity, the symp-toms persist. For example, a carbon monoxide emitting gas heater may onlyoperate in the morning and not in the afternoon. The occupants developsymptoms that persist throughout the day, beyond the time of exposure. Theenvironmental professional assesses the area in the afternoon only to findlow or no carbon dioxide exposure.

So, be prepared to investigate any and all possibilities wherein carbonmonoxide poisoning is suspect. A good, solid sampling strategy is a must!

Sampling Strategy

Occupants in an office space complained of severe headaches, nausea, andchronic fatigue that persisted into the weekend. The office space is locatedabove industrial activities where by propane forklift trucks are operatingconstantly. In the morning, diesel trucks back up to loading docks andremain running for the duration of the loading process. The exhaust plumefrom the trucks had been observed blowing toward the building eaves andoccasionally into the air intake for the office spaces.

The evidence was overwhelming that carbon monoxide was the culprit,but air monitoring was met with resistance from the industrial teaser of theoffice space. As the sampling strategy turned into an intense chess game,the investigator should be aware that the obvious may become an unri-valed challenge.

The investigator should perform air monitoring for carbon monoxidewhenever complaints include symptoms of carbon monoxide poisoningand a potential source has been identified. Even if an unidentified or indus-trial exhaust source is merely suspect, the investigator should perform airmonitoring.

When the source has been identified, one worst case sample may be takenfor diagnostic (not exposure) monitoring at the source. Do not take the sam-ple at the breathing zone of the occupant(s) since by the time the carbonmonoxide reaches them, the level of exposure will be considerably dimin-ished and not as easily identified. So, first, attempt to identify the worst casescenario at the source and, second, determine the occupant(s) exposure. Oneoccupant exposure should be minimal.

As the time of occurrence may not be clear, ongoing monitoring should beperformed for the duration of the building occupancy. In an office building,occupancy may occur from 7 a.m. to 6 p.m. In a residence, occupancy mayinclude 24 hours. In long-term sampling, if the monitoring equipment is leftunattended, the investigator should check prior to sampling to determine if


the suspect event is likely to occur and confirm the occurrence of the eventafter sampling. For instance, if the suspect event is early morning dieseltruck traffic and the trucks fail to deliver on a morning when they werescheduled, sampling should be rescheduled for a time to include truckdeliveries.

If attempting to sample in a confined air space (e.g., closed conferenceroom), confirm the doors remained closed during the sampling period. Ifyou place a “do not disturb” sign on the door and on the monitor, do notassume compliance. Some additional measures may be needed to assure thearea is secured.

In urban environments, always take an outside background air sample forcomparison. Where the investigator monitors elevated levels indoors, out-door air sampling should be performed. All contributing outdoor sourcesshould be recorded.


Whereas direct reading instrumentation or colorimetric detectors both pro-vide instantaneous data, the direct reading instrumentation provides ongo-ing data. There are higher initial costs for instrumentation, but detector tubesinvolve a low cost per sample. The desired number of samples and accessibil-ity of equipment are important considerations to choosing the more practicalapproach to air sampling.

Direct Reading Instrumentation

If a large number of data points are to be collected and equipment is read-ily available, direct reading instrumentation is the most feasible approach.They are available both for purchase and for rental. For low usage and mini-mal maintenance situations, rental is the most practical means for accessingequipment.

Carbon monoxide monitoring equipment may be purchased or rentedas dedicated units or part of a four-gas monitor. Most are data logginginstruments that record time-exposure data. Some have a recorder thatprovides ongoing data that is recorded onto a strip chart while otherssimply provide a digital readout of data points that the investigator mustrecord on paper. See Figures 11.1 and 11.2.

Colorimetric Detectors

Colorimetric detection is the most feasible approach wherever a small num-ber of data points are to be collected and direct reading equipment is not

CarbonMonoxide 189

readily available. For up to 10 samples, colorimetric detectors are more eco-nomical than direct reading instrumentation.

Colorimetric detection of carbon monoxide is based on a reaction withchemicals contained within the detector tube. A color change occurs, andthe length of the discoloration (e.g., Drager® white to brownish green) is themeasure of concentration.

Sampling requires a handheld bellows or piston pump and carbon monox-ide detector tubes. The pump and tubes must be made by the same manufac-turer. The tubes are chemical specific with different ranges (e.g., 2 to 60 ppmand 8 to 150 ppm).

As concentration is difficult to read, results may be off by as much as50 percent. Although this method lacks accuracy, the range of ± 50 percenthas minimal impact.

Although there are several potential interferences or cross-sensitivities forcarbon monoxide detector tubes, they may be filtered with a carbon prefil-ter. The potential cross-sensitivity chemicals are petroleum hydrocarbons,

FIGURE 11.1Single gas direct reading data logger—EL-USB-CO meter. (Courtesy of Lascar Electronics).

FIGURE 11.2Multiple gas direct reading data logger with carbon monoxide sensor—MultiRAE® ToxicsMonitor measures carbon monoxide, volatile organic compounds, hydrogen sulfide, and com-bustibles (Courtesy of RAE Systems, San Jose, California).


benzene, halogenated hydrocarbons, and hydrogen sulfide. For example,halogenated hydrocarbons (e.g., trichloroethane) in high concentrations candiscolor the indicating layer to a yellowish brown.

The sampling method is summarized as follows:

• Equipment: bellows or piston pump• Sampling media: carbon monoxide detector tubes in desired range• Procedure: insert tube in pump holder with arrow pointing toward

the pump, squeeze and release the pump for the number of strokesdesigned by the manufacturer (1 to 10 times), allowing the pumpbellows or piston to fill completely between each stroke

• Analysis: read the concentration on the basis of the perceived lengthof the color change

Helpful Hints

Take prolific notes, and record sample locations on a building schematic.There is great truth in the old adage “a picture says a thousand words.”Record the precise sample locations and sample times, and sketch the sam-ple location wherever possible. Also be certain to record the time each datapoint was collected, conditions, and activities that may impact the interpre-tation of results.

Be particularly cautious whenever intending to leave data logging equip-ment unattended for an extended period of time. Murphy’s law may beinstituted during an abbreviated departure from the sample site, particu-larly where another party may benefit by altered conditions. In other words,“Anything that can go wrong, will go wrong.” Count on it!


Enforceable limitsandnonenforceableexposureguidelines forcarbonmonoxideare 9 ppm (Environmental Protection Agency, EPA), 50 ppm (OccupationalSafety and Health Administration, OSHA), 10 ppm (World Health Organization,WHO), 35 ppm (National Institute for Occupational Safety and Health, NIOSH),and 25 ppm (American Conference of Governmental Industrial Hygienists,ACGIH). Whichever standard/guideline was used in the past has changed!

The Leadership in Energy and Environmental Design (LEED) and AmericanSociety of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE)189.1 “maximum concentration limit” for carbon monoxide exposures in

CarbonMonoxide 191

nonoccupatonal, indoor air quality assessments is 9 ppm or not greater than2 ppm above background carbon monoxide levels. Background carbon mon-oxide levels in rural environments are typically zero, but background levelsin a city (e.g., high vehicle traffic) or around industrial environments mayexceed 9 ppm.

The LEED and ASHRAE guidelines for carbon monoxide indoors are inline with the EPA enforceable limits for outside air with but one caveat. Ifthe outside air exceeds 9 ppm, the LEED and ASHRAE guidelines raise thelimit to 2 ppm above the outside carbon monoxide levels. For instance, if theoutside carbon monoxide level is 10 ppm (EPA noncompliance for 8-hourexposures), the indoor air quality limit becomes 12 ppm.

Summary

Carbon monoxide monitoring should be performed whenever carbon mon-oxide poisoning is suspect and where there is a known source in or aroundthe complaint area. The symptoms may be elusive wherein carbon monoxideis slightly elevated, and all sources of carbon monoxide may not be obvious.

If monitored exposures are below the 9 ppm limits and carbon monoxidepoisoning is suspect or confirmed (e.g., blood carboxyhemeglobin testing),ask questions and perform additional sampling. Due to the extensive timerequired for carbon monoxide to dissipate from hemoglobin, an investiga-tion may prove to be very challenging. Long-term data monitoring is ideal!

Reference

1. Proctor, N.H., and J. Hughes. Chemical Hazards of the Workplace. J.B. LippincottCompany, Philadelphia (1978), p.152.

193

12Formaldehyde

As one of the 27 components identified within the Milky Way and with anestimated 21 million tons annually produced worldwide, formaldehyde iseverywhere! It is indoors and outside, naturally occurring and manmade. Itis a by-product of combustion. It is used in the production of home and officeproducts. It is used in cosmetics, and it is in many of our foods both naturallyand as a contaminant.

Due to its ubiquitous nature and extensive use, formaldehyde was origi-nally the target health hazard in indoor air quality investigations from thelate 1970s until just recently. Known health effects due to low-level expo-sures typically found in indoor air quality include irritation of the eyes, nose,and throat. Symptoms may include watery eyes, burning eyes and nose,and coughing. People chronically exposed to low levels may also experi-ence asthma, chronic bronchitis, severe headaches, sleep disorders, chronicfatigue, and nausea.1 In more severe cases, there may be lung irritation andbronchospasm.

More elevated acute exposures may include coughing, wheezing, chestpain and tightness, increased heart rate, and bronchitis. There have also beenreports of asthma attacks, nausea, vomiting, headaches, and nose bleeds.Exposures in excess of that normally found in indoor air quality situations(e.g., industrial exposures) may result in pulmonary edema, pneumonitis,and death.

Dermal exposures may result in skin irritation, contact dermatitis, andallergic sensitization. In some cases, symptoms involve eczema to the eye-lids, face, neck, scrotum, and flexor surfaces of the arms. Sometimes dermalexposures may involve the fingers, back of the hands, wrists, forearms, andparts of the body exposed to friction.

There are several peculiar health effects of low-level formaldehyde expo-sures encountered in indoor air quality complaints that are not commonlyreported in industrial exposures. These include sleeping difficulties, anxiety,fatigue, unusual thirst, dizziness, diarrhea, menstrual cramps, and memoryloss. In one instance, a woman thought low-level exposures in her mobilehome caused her to experience a feeling of persecution. People were alleg-edly following her, and she attacked an unsuspecting passerby and was laterarrested for attempting to strangle the stranger.

According to the American Conference of Governmental IndustrialHygienists (ACGIH), formaldehyde is a suspect human carcinogen.


A sevenfold cancer risk occurred during industrial operations whereexposures were excessive, higher than that of the normal population.2

Although a volatile organic compound, formaldehyde is too volatile andlow in molecular weight to be captured and analyzed by the sampling meth-ods for a broad spectrum of volatile organic compounds. For this reason,formaldehyde is addressed separately herein.

Occurrence of Formaldehyde

In 1994, the U.S. Environmental Protection Agency (EPA) reported ambientexposures in urban outdoor air environments to be 11 to 20 ppb. These expo-sures are in contrast to the more than 2.4 million mobile home dwellers thatare constantly exposed to an average of 400 ppb formaldehyde annually. Therange of reported exposures in homes is 0.10 to 3.68 ppm. See Table 12.1 forformaldehyde exposure levels and associated health effects.

Environmental ambient air exposures are predominantly the result ofcombustion byproducts with significant contributions from motor vehicleexhaust. Other contributors are power plants, manufacturing facilities, andincinerators. Heavy smog due to urban combustion may reach ambient airlevels as high as 0.1 ppm.

Indoors and outside combustion products that contribute to the formalde-hyde levels include the following:

• Gasoline• Wood• Natural gas• Kerosene• Cigarettes

TABLE 12.1

Formaldehyde Exposure Levels and Reported Health Effects

Exposure Level(s) Health Effects

0.05–1.0 ppm pungent odor0.01–2.0 ppm eye irritation1.0–3.0 ppm irritation of eyes, nose, respiratory tract, throat,

and upper respiratory tract4.0–5.0 ppm unable to tolerate prolonged exposures10.0–20.0 ppm severe respiratory symptoms and difficulty

breathing>50 ppm serious injury to the threshold

Formaldehyde 195

These source contributors are rarely considered significant contributors tothe formaldehyde levels indoors.

In office buildings, the most common indoor sources of formaldehydeare off-gassing from building materials and office furnishings. Knownbuilding materials that off-gas formaldehyde are formaldehyde-bondedresin products such as foam insulation, plywood, particleboard, press-board, wall panels, and wood finishes. The most commonly used indoorresin is water soluble urea-formaldehyde. Outdoor resins are phenol- andmelamine-formaldehyde.

Other building materials potentially composed of urea-formaldehyde arefiberglass HVAC duct board, fiberglass insulation, and carpet backings. Newoffice furnishings manufactured with formaldehyde-containing resins (e.g.,veneered particleboard desks) are significant contributors to office formalde-hyde exposures. Whereas formaldehyde off-gassing of furnishings generallytakes place within the first months of purchase, older furniture is rarely acontributor to elevated levels of formaldehyde in the air.

Formaldehyde-containing products may also contribute to office andresidential exposures. These may include but are not limited to paperproducts, deodorants, fabric dyes, inks, disinfectants, deodorizers, airfresheners, cleaners, pesticides, preservatives, paints, and permanentpress clothing.

In residential environments, many of the same building products and fur-nishing found in office buildings are contributors to elevated levels of form-aldehyde. Prior to strict manufacturing specifications and state regulations,the highest residential exposures were associated with mobile homes andconventional residences insulated with urea-formaldehyde foam.

In one report, “green rated” homes in California were found to have higherlevels of formaldehyde than conventionally built homes. The rationale is thatthe green rated home were tighter, more energy efficient that those not rated.They energy efficient home are more airtight and have minimal air infiltra-tion of outside air.3

Beyond the previously mentioned airborne exposures, individuals inadver-tently contribute to their own exposures by applying or using products thatcontain formaldehyde. Formaldehyde is used in cosmetics, shampoos, phar-maceutical products, and permanent press clothing. If the container does notstate the presence of formaldehyde, look for Quaternium. Quaternium 15,a formaldehyde release agent, and similar preservatives (e.g., diazolidinylurea) are found in conditioners, deodorant soaps, hairspray, styling mousse,fluoride toothpaste, mouthwash, mascara, talcum powder, hair coloring, andfingernail polish. These should be considered suspect wherein an individualhas localized dermal complaints.

The National Academy of Science estimates that 10 percent to 20 percent ofthe general population is susceptible to the irritating properties of formalde-hyde at levels below 0.1 ppm.4 In combination with other airborne irritants,formaldehyde may also have an additive or synergistic impact of building


occupants. Be forewarned! Complaints of eye, nose, and respiratory tractirritation may be the result of exposures to formaldehyde and a number ofother airborne contaminants. Low-level formaldehyde exposures may bethe cause of health complaint, but it may contribute to the overall effect. SeeTable 12.1.

Some studies indicate that children exposed to 0.03 ppm had decreasedlung function. When exposed to levels between 0.60 and 0.12 ppm, childrenwere more likely to have asthma or chronic bronchitis.5

Relative humidity, temperature, air movement, and ventilation rates sig-nificantly affect formaldehyde off-gassing and airborne exposure levels.For every 10°F increase in temperature, formaldehyde off-gassing doubles.For an increase in relative humidity from 30 percent to 70 percent, theoff-gassing may increase as much as 40 percent. Increased air movementwill minimize stagnant air pockets and localization of gaseous formalde-hyde at the point of off-gassing. Although ventilation flow rates will dilutecontaminated air, scenarios where the return air is in the immediate vicin-ity of the supply air may result in localized recycling and movement of air.The ideal configuration, rarely encountered, is the return air and supply atremote sites to one another or the air is diluted by outside air taken into theHVAC system.

Sampling Strategy

At a minimum, samples should be taken within the area of greatest com-plaints, a noncomplaint area, and outside. The investigator should identifythese areas and be clear as to the worst case sites based on the complaintsand on odor. As there are no known direct reading instruments capable ofmeasuring formaldehyde at the levels generally found in indoor air qualityinvestigations, instrument screening is out of the question.

For exposure monitoring, samples should be taken within the vicinity ofthe occupants’ breathing zones, not up in the far corner of the ceiling, andall samples should be area samples, not personnel samples. The only occa-sion when sampling at ground level should be considered is when there isconcern regarding exposures to a small child. However, diagnostic samplingis a separate issue.

Diagnostic sampling may be performed for source identification. Thismay be done either during the exposure monitoring or after excessiveexposure levels have been determined. In all cases, several samples takenat the same time will assist the investigator to contour an area regardingrelative concentrations. Whether taken during or after the initial exposuremonitoring, diagnostic samples should also include at least one exposure

Formaldehyde 197

sample taken at the same time. If the initial sample has already been taken,take another at the same location. This will allow for changed conditionsand probable different exposure levels from one sampling period to thenext.

At a minimum, samples should be collected during those times antici-pated to include excessive exposures, and the air handling system shouldbe operating as it generally is during complaint periods. In an officebuilding, if the complaints occur in the evening when the air handler hasbeen minimized, the samples should be taken in the evening with theair handler minimized. Try to sample during those times and conditionssimilar to when complaints occur.

At a minimum, samples should be collected for the length of time that willallow detection to the level(s) targeted for concern. See flow rates, maximumair sample volumes, and lowest detection limit in Table 12.2.

Other important sampling strategies involve anticipated physical state andinterferences. This topic is addressed in the next section.


Most formaldehyde air sampling methodologies collect on the basis ofphysical state. Formaldehyde is a highly water soluble gas that readilymixes with water to form formalin, which is a liquid. Formalin vaporsmay or may not be captured by those methods that are meant only to col-lect the gas phase, and formalin vapors are just as irritating as formalde-hyde gas. Should formalin become adsorbed onto dust particles, the gasphase collection methods prefilter dust particles. Where dust may poten-tially carry formalin that contributes significantly to exposure levels andhealth effects, choice of a gas collection method will result in incompleteinformation.

Most of the air sampling methods (i.e., NIOSH 2016, NIOSH 2541, OSHA52, and EPA IP 6A) will capture formaldehyde in its gaseous phase. They aresimilar in equipment requirement, collection media and flow rate restric-tions. The differences are in the detection limits (which in indoor air qualityare important), sampling duration, laboratory analytical methods, and inter-ferences (or specificity).

Whereas the EPA IP 6A method involves longer sampling periods (up to 50hours), greater detection limits (0.001 ppm), and may involve ozone interfer-ences, Occupational Safety and Health Administration (OSHA) 52 involvesconsiderably less sampling duration, less detection limits (0.25 ppm), with nointerferences, and NIOSH 2016 requires less sampling duration with greater


TAB

LE 1

2.2

Form

alde

hyde

Air

Sam

plin

gM

etho

dolo

gies

Met

hod

Col

lect

ion

Met

hod

Flow

Rat

e(s)

(l

iter

s/m

in)

Max

imu

m A

ir

Sam

ple

Vol

um

e L

owes

t D

etec

tion

Lim

ita

An

alyt

ical

M

eth

ods

Inte

rfer

ence

s

NIO

SH20

16E

PATO

-11

(gas

phas

e)

trea

ted

silic

age

lsor

bent

0.1–

1.5

15lit

ers

0.18

ppm

HPL

C/

UV

ozon

e

NIO

SH25

41(g

asph

ase)

trea

ted

XA

D-2

sorb

ent

01–0

.110

0lit

ers

0.25

ppm

GC

/FI

D–

OSH

A52

(gas

phas

e)tr

eate

dX

AD

-2so

rben

t0.

01–0

.124

liter

s0.

04pp

mG

C/

NPD

–

NIO

SH35

00(a

llph

ases

)2

impi

nger

sin

line

wit

h0.

2–1.

036

liter

s0.

025

ppm

VA

Sph

enol

and

10%

sod

ium

bisu

lfite

oxid

izab

leso

luti

onor

gani

csN

IOSH

5700

(sol

idph

ase)

5-m

icro

nPV

Cfil

ter

210

50lit

ers

0.00

03pp

mH

PLC

/U

V–

EPA

IP-6

A(g

asph

ase)

trea

ted

silic

age

lsor

bent

0.1

300

liter

s0.

001

ppm

HPL

C/

UV

ozon

e

Not

e:H

PLC

/U

V=

high

pres

sure

liqui

dch

rom

atog

raph

y/U

Vd

etec

tor;

GC

/FI

D=

gas

chro

mat

ogra

phy/

flam

eio

niza

tion

det

ecto

r;G

C/

NPD

=ga

sch

rom

atog

raph

y/ni

trog

enph

osph

orou

sd

etec

tor;

VA

S=

visu

alab

sorp

tion

spec

trom

etry

.a

Bas

edon

the

publ

ishe

dra

nge

and

max

imum

air

volu

me.

Formaldehyde 199

detection limits than the OSHA 52 method. Each of the gaseous phase sam-pling methods has a slight variation in capability, and in order to conduct athorough survey, the investigator must consider these differences and weighthem against the sample information sought. For instance, the ASHRAE189.1 limit for formaldehyde is 33 µg/m3 (or 26 ppb) and the LEED limit forformaldehyde is 50ppb (see Chapter 19, “Green Buildings”). Both requireminimum sample duration of 4 hours. When attempting to attain these lim-its, NIOSH 2016 has become the preferred choice.

The NIOSH Method 2016 is the best all-around sampling method for mini-mal sample duration and detection limits. The sampling methodology is asfollows:

• Equipment: air sampling pump• Capture media: silica gel treated with 2,4-dinitrophenylhydrazine

(e.g., SKC 226-119)• Flow rate: 0.1 to 1.5 liters/minute• Air volume limits: 15 liters• Field blanks: minimum of one for up to ten samples in any given

sampling period• Analysis: HPLC-UV detector• Limit of detection: 0.1 µ/sample (6.7 µ/m3 for 15 liter sample)• Special handling and shipping instructions: none

Experience comes knocking. On occasion, formaldehyde adheres to thesurface of dust particles, which are prefiltered prior to the solid sorbent.Only gaseous formaldehyde gets through. NIOSH Method 3500 is a goodall around method for sampling the gaseous, liquid vapor (e.g., formalin),and solid particle (e.g., formalin adsorbed onto the surface) phases of form-aldehyde. Yet sampling is more difficult. The collection medium is a liquidthat is easy to spill (particularly when transferring the liquid into a smallplastic container for shipping) and during shipping, poorly sealed contain-ers can leak. It is not unusual for a sample to arrive at a laboratory withonly a drop of liquid in the bottom of the container. Furthermore, duringextended sampling periods, the collection liquid vaporizes. Although theliquid can be replenished as it vaporizes, the investigator must frequentlycheck the liquid levels during monitoring. This approach also requiresless sampling time while providing a good detection limit. Also, analyti-cal interferences are minimal. In NIOSH 3500, phenol may be a positiveinterference. Although low levels of phenol may contribute a 15 percentbias, phenol is rarely encountered in indoor air quality investigations, andseparate sampling can be performed to rule out phenol. Slight negative


interferences may also result from alcohols, olefins, aromatic hydrocarbons,and cyclohexanone. This method also calls for the use of a 1-micron PTFEmembrane filter prior to the two impingers if the environment is dusty.However, the use of a filter precludes formaldehyde adsorbed into the sur-face of particles. For this reason, an investigator may choose to use NIOSH3500 without the filter particularly where there are no excessive levels ofdust. NIOSH 3500 method is summarized as follows:

• Sampling equipment: air sampling pump and two impingers• Collection medium: 1% solution of sodium bisulfate (20 mL of solu-

tion per impinger)• Flow rate(s): 0.2 to 1 liter/minute• Field blanks: minimum of one for up to ten samples in any given

sampling period• Sample duration: 100 minutes• Detection limit(s): 0.025 ppm• Handling: transfer sampled solution and ship in special 50 mL low-

density polyethylene bottles• Special considerations: most laboratories are no longer set up to ana-

lyze in accordance with NIOSH 3500

NIOSH 5700 was created specifically for sampling wherein formalin carry-ing dust is suspect. In some instances, the investigator may choose to usethis method with a gaseous phase method in order to assure collection of allairborne formaldehyde/formalin. All other methods filter out the dust par-ticles, potentially minimizing the actual airborne formaldehyde exposures.There are no interferences and the detection level is low (e.g., 0.0005 ppm). Asummary of this method follows:

• Sampling equipment: air sampling pump and inhalable dust sampler• Collection media: 25 mm PVC filter• Flow rate(s): 2 liters/minute• Field blanks: minimum of one for up to ten samples in any given

sampling period• Sample duration: 36 to 180 minutes• Detection limit(s): 0.025 ppm• Handling: transfer sampled filter and ship in special 30 mL low-

density polyethylene bottles

See Table 12.3 for a recap of the different methodologies.

Formaldehyde 201

Analytical Methodologies

In NIOSH 2016, EPA TO 11, and EPA IP 6A, where the collection mediumis silica gel treated with 2,4 dinitrophenylhydrazine (DNPH), formaldehydecombines with the DNPH on the silica gel to form a 2,4 dinitrophenylhydra-zone derivative. The derivative is analyzed by high-pressure liquid chroma-tography with an ultraviolet light detector. Ozone may consume the DNPHand interfere with the conversion of formaldehyde to the oxazolidine analyte.Thus where elevated ozone levels are anticipated or known, these methodsmay not be the best choice for sampling.

Where the collection medium is specially treated XAD 2, formaldehydecombines with the 10% (2 hydroxymethyl) piperidine to form an oxazolidinederivative. The derivative is analyzed by gas chromatography with a flame ion-ization detector. NIOSH 2541 calls for nitrogen phosphorous detector (NPD) inorder to increase the analytical sensitivity, and OSHA 52 specifically directs itsuse. Although there are no observed interferences with either of these meth-ods, acid mists may inactivate the sorbent, leading to inefficient collection offormaldehyde. Thus where acid mists are anticipated or known, NIOSH 2541and OSHA 52 may not be good choices of sampling methods.

In NIOSH 3500, also referred to as the “chromotropic acid method,”formaldehyde, not a derivative of formaldehyde, is the actual analyte.During sampling, the formaldehyde is settled out by the sodium bisulfitesolution. At the laboratory, it is mixed with chromotrophic acid and sul-furic acid. A color develops, and analysis is performed by visible absorp-tion spectrometry. If there is interference by other aldehydes, the effectis minimal.

In NIOSH 5700, the collected dust is extracted with distilled water andmixed with 2,4 dinitrophenylhydrazine/acetonitrile (DNPH/ACN). The deriv-ative is then analyzed by high-pressure liquid chromatography with anultraviolet light detector. This is similar to NIOSH 2016, EPA TO 11, and EPAIP 6A and has the same ozone interference.

TABLE 12.3

Formaldehyde Solid Sorbent Tubes

Method Type of Sorbent

NIOSH 2016/EPA TO-11 Silica gel treated with2,4-dinitrophenylhydrazine (DNPH)

NIOSH 2541/OSHA 52 XAD-2 treated with10% (2-hydroxymethyl) piperidine


Helpful Hints

When performing NIOSH 3500, check frequently for retention of solutionand attempt to maintain the level up to 20 milliliters with fresh solution.Upon sample completion, transfer each sampled solution to a separate prop-erly labeled plastic bottle, clean, and add the extra to solution for transportto the laboratory. Seal each bottle with a stretch tape (e.g., electrician’s tape)and pull around the seam in the direction that the cap turns to allow for amore airtight fit. Record the level of solution in the container prior to ship-ping and report it with the air volume for Impinger I (first impinger) andImpinger II (backup).

Given a low flow rate and backup section or solutions, the investigatormay sample for a longer duration, sample greater air volumes, and get bet-ter detection limits with reliable results. For instance, if the investigatorsamples for 5 hours instead of 2½ hours at a flow rate of 0.1 liters per minuteusing NIOSH 2016, detection levels can be improved from 0.18 to 0.09 ppm.Most experienced industrial hygienists will not push the envelope. If youdo, however, do it with a backup to confirm completeness and reliability ofthe sample(s).


The American Society of Heating, Refrigerating and Air ConditioningEngineers (ASHRAE) 189.1 “maximum concentration limit” for formaldehydeexposures in nonoccupatonal, indoor air quality assessments is 33 µg/m3

(or 27 ppm). The Leadership in Energy and Environmental Design (LEED)limit is 50 ppm, twice that of ASHRAE 189.1.

Enforceable limits and nonenforceable exposure guidelines, referencedin previous indoor air quality assessments, were 750 ppb (OSHA), 100 ppb(WHO), 16 ppb (NIOSH), and 300 ppb (ACGIH). Formaldehyde is knownto cause eye irritation at 10 ppb, and the outdoor ambient levels have, insome studies, been recorded as high as 100 ppb. There are no outdoor EPAlimits for formaldehyde, and the 100 ppb limit covers most, not all, healthconcerns.

The maximum limits of 27 ppm, as set by ASHRAE 189.1, may not be attain-able in all cases due to outdoor levels. In these rare circumstances, comparethe indoor with outdoor air samples. The ASHRAE guideline will be verydifficult to attain in indoor air quality. The environmental professional willbe required to make his or her own judgment!

Formaldehyde 203

Summary

There are pitfalls with each of the sampling techniques. The investigatormay use one or a combination of these methods, depending on the situation.Consider the physical characteristics (e.g., gas versus carried by a solid), detec-tion limits (0.0003 to 0.25 ppm), interferences (e.g., ozone), sampling duration(2 to 50 hours), and ease of sample management. Sampling requirements willvary, depending on each separate circumstance.

An action level for indoor air quality exposures is precarious and rela-tive to other environments. The most commonly accepted limit of 0.1 ppmhas boundaries and exceptions as well. With each new case, the investigatorplays a new deck of cards!

References

1. Kincaid, L., and B. Offerman. Unintended Consequences: FormaldehydeExposures in Green Homes. The Synergist (February 2010), p. 31.

2. National Cancer Institute. Cancer Facts/Risk Factors. http://cancemet.nci.nih.gov/clinpdq/risk/Formaldehyde.html (December 22, 2000).


4. Formaldehyde Alert! http://members.tripod.com/gentlesurvivalistformaldehyde.html (December 22, 2000).


205

13ProductEmissions

Indoor exposures to organic compounds are typically two to five timeshigher than those found outdoors. This is primarily attributed to emis-sions from construction materials, furnishings, office supplies/equip-ment, fixtures, and maintenance/cleaning products. Other contributingsources include individual use products (e.g., perfumes and lighters) andoutdoor air pollutants. Indoor air pollutants are truly a wonderland ofsurprises!

Then, indoor industrial exposures to toxic substances are generally10 to 100 times those found in nonindustrial environments. This extremedifference raises a skeptical eyebrow whenever environmental profes-sionals respond to office building complaints. Exposures are muchlower in nonindustrial environments while complaints are greater. Whyare the health complaints in office buildings disproportionate to thosein industry?

Some feel the discrepancies lie in the complex array of chemical expo-sures in offices and other nonindustrial environments. Furthermore, nonin-dustrial environments are generally exposed to low levels of more than 300chemicals—an amalgam that may exceed high industrial exposure levels toa limited number of chemicals. The combination of overwhelming numbersand the synergistic irritant/health effects of indoor air contaminants set thestage for occupant health complaints. This scenario is exacerbated by typeof containment(s) and level of buildup.

Due to increased energy efficiency needs and reduced makeup air, indoorair is ripe for the buildup of airborne contaminants. Whereas in industrialenvironments chemicals are removed by local exhaust and dilution ventila-tion, energy efficient, tight buildings retain most air contaminants. Trappedchemicals do not a good bedfellow make!

From whence do the chemicals come? They come from components offurnishings, equipment, fixtures, flooring, and cleaning products, a medleyof trapped chemicals. In new buildings, construction materials and prod-ucts contribute significantly as well. The pressure cooker builds! There is noplace for chemicals to escape. Subsequently, product emissions in confined,occupied spaces have become the bane of “sick building syndrome.” Whatto do?


Global Response and Product Labeling

As early as 1978, the Germans introduced the “Blue Angel.” This was, and stillis, a certification program for environmentally “friendly” products and services.Other countries began to mimic the Germans and began developing their own.Out of this arose the Nordic Swan, Canadian Environmental Choice, U.S. GreenSeal, and others—all eventually becoming part of an international cooperative.

In 1994, Global Ecolabelling Network (GEN) was formed to put a globalface on labeling. Its express purpose was to “improve, promote, and developthe ‘ecolabelling’ of products and services.” By 2007, membership had grownto include 26 nations and multinational organizations (see Table 13.1).

TABLE 13.1

Global Ecolabelling Network Members

Australia Good Environmental Choice Australia Ltd.Brazil Associacae Brasileira de Normas Tecnicas (ABNT)China China Environmental United Certification CenterCroatia Ministry of Environmental Protection and Physical PlanningCzech Republic Ministry of the EnvironmentEU European Commission–DG Environment (G2)Germany Federal Environmental Agency (FEA)Hong Kong (GC) Green CouncilHong Kong (HKFEP) Hong Kong Federation of Environmental Protection (HKFEP)

LimitedIndia Central Pollution Control Board (CPCB)Indonesia Ministry of EnvironmentJapan Japan Environment Association (JEA)Korea Korea Eco-Products Institute (KOECO)New Zealand Environmental Choice New ZealandNordic Five Countries Nordic Ecolabelling BoardNorth America (Canada) Terra Choice Group Inc./Terra Choice Environmental

Marketing, Inc. (for Environment Canada)North America (USA) Green SealPhilippines Clean & Philippine Center for Environmental Protection and

Sustainable Development, Inc. (PCEPSDI)Russia Saint-Petersburg Ecological UnionChinese Taipei Environment and Development Foundation (EDF)Singapore Singapore Environment CouncilSweden (SSNC) Swedish Society for Nature Conservation (SSNC)Sweden (TCO) TCO DevelopmentThailand Thailand Environment Institute (TEI)Ukraine Living PlanetUnited Kingdom Department for Environment, Food and

Rural Affairs (DEFRA)

ProductEmissions 207

Ecolabeling is a voluntary method of environmental performance certi-fication and labeling that is practiced around the world. An “ecolabel” is alabel that identifies overall environmental preference of a product or ser-vice within a specific product/service category based on “life cycle consid-erations.” In contrast to “green” symbols or claim statements developed bymanufacturers and service providers, an ecolabel is awarded by an impartialthird party in relation to products or services that are independently deter-mined to meet environmental leadership criteria.1

Standards of Green Seal, a U.S. component of GEN, meets criteria as setforth in: (1) ISO 14020 and 14024, the standards for ecolabeling; and (2) theU.S. Environmental Protection Agency (EPA). Currently, the Green Seal labelis limited to industrial/institutional cleaners and paints.

Although not in the Global Ecolabelling Network, Green Label is anindustry-monitored, third-party certification for carpets and carpet padsthat is managed by the Carpet and Rug Institute (CRI). The Green Label andGreen Label Plus programs certify the “lowest” emitting carpet, backing-adhesive, and cushion products on the market.

In 2001, a U.S. based emissions testing laboratory established theGREENGUARD Environmental Institute (“GREENGUARD”) to test andcertify indoor air emissions from office furniture and office equipment.GREENGUARD, which is the only ISO 65 accredited certification programin the United States, developed the initial testing methodology for officefurniture through EPA’s Environmental Technology Verification Program.GREENGUARD had previously been accredited by Germany’s FederalInstitute for Materials Research and Testing for providing acceptabledata for the Blue Angel Eco Label Program. Today, it has developed test-ing methodologies that not only evaluate office equipment and furniturebut much more. It performs third-party testing and certification for thefollowing:

• Cleaners and cleaning maintenance products• Office, institutional, and residential furniture• Office equipment (e.g., printers, multifunction machines, fax machines,

and copiers)• Building materials, finishes, and indoor furnishings• Electronic equipment (e.g., computers, video monitors, and televisions)

As public concerns escalate, manufacturers and builders seek to producelow-emission products. The downside is cost. It is speculated that the cost forgoing “green” increases product costs 20 percent or more. The cost differencemay change as the market adapts, but for now, end user “suspect” productemissions testing is a viable alternative!


Product Emissions Awareness

Product emissions testing had been the wave of the future, and the future isupon us. Testing is with greater frequency becoming a mandate. The manu-facturers who seek Global Ecolabelling Network certification are limited asto what can be certified. Building owners request environmentally friendlyor “green” products and request information to this effect from the manu-facturers and suppliers. If the products are not labeled, and most aren’t, thesalesperson may say, “Trust me! My product has no emissions” or, “We havenever had any complaints.” They are likely, however, to seek validation fromthe manufacturer who also wants to make a sell.

Most products are a composite of multiple intermediate products. Forinstance, the components that make up a desk include plywood, laminateadhesives, glues, stains, varnishes, and shellac. Hence, a manufacturer whohas a genuine desire to provide information often finds the task of compilingall the data (e.g., MSDS) can be overwhelming. Emissions testing is expen-sive and time-consuming. The price tag of furniture that has already beentested may override the cost of purchasing a pig in a poke and testing later.

Many facility managers require prefurnishing and postfurnishing airmonitoring prior to occupying a new office building. Postoccupancy airmonitoring is generally, not always, complaint driven. Wherein air monitor-ing demonstrates chemical levels of concern, the environmental professionalmay seek to identify suspect products for testing. Identifying the culprit(s)requires product emissions awareness!

In indoor air quality, air contaminants most frequently encountered arevolatile organic compounds (VOCs) and formaldehyde (see Table 13.2). VOCexposures are chemical specific. Formaldehyde, an organic compound, cancause eye irritation (inflammation, redness, itching, and watery) and is listedas a suspect human carcinogen by the American Conference of GovernmentalIndustrial Hygienists (ACGIH).

Carpet and carpet backing off-gas both VOCs and formaldehyde. Of the manyidentified VOCs, 4-phenylcyclohexene (4-PCH) is the target component that hasreceived the most attention. Generally associated with wall-to-wall, rubber-backed carpeting, 4-PCH gives off a distinctive “new carpet” odor and causesnose and upper respiratory tract irritation. 4-PCH is a “by-product” of the copo-lymerization of styrene-butadiene when the conditions are not optimal. In oneheadspace emissions study, 4-PCH was the most abundant of 10 VOCs foundin carpet made with laminated fabric backing. Air concentrations measured inbuildings after installation of new carpet has been reported at 0.3 to 2.6 ppb.3

Carpet component 4phenylcyclohexeneRecommended exposure limit—noneOdor threshold—0.3 ppb (2 µg/m3)


In a German study, 4-PCH was rated as “odor active” and contributed topoorly perceived indoor air quality.”4 They reported that low-level exposuresof 4-PCH and other VOCs were associated with headaches, eye irritation,and nausea.5

In 1989, the Consumer Product Safety Commission and the EPA performed astudy of new carpet emissions and the adverse effect on human health. Therewere 206 households involved in new carpet installations and no controls.Relative incidences were not reported either. So the reported symptoms are acomposite, not related to frequency. The symptoms began either immediatelyor within several days of newly installed carpet. Reporting included upperrespiratory tract problems; eye irritation; headaches; rashes; fatigue; difficultyin concentration; headaches; nausea; excessive thirst; dry mouth; burning ofthe eyes, nose, and sinuses; incoherent speech; depression; sore throat; itchyskin; burning feet and legs; chronic rhinitis; and dry, puffy, irritated lips.

The CRI Green Label Plus only assures the customer of “very low” VOCemissions. The label is no assurance that the carpet is free of VOCs. Underthe program, all carpet products are tested by an independent laboratory.Thirteen chemicals that have been identified with carpet are:

• Acetaldehyde• Benzene

TABLE 13.2

Products That Result in VOC and Formaldehyde Emissions2

Volatile Organic Compound Emissions Formaldehyde Emissions

Paints ParticleboardFabrics and fabric treatments PlywoodCushions (polyurethane/polystyrene foamand polyester stuffing)

PressboardPaneling

Plastics (various plasticizers) CabinetryAdhesives Carpet/carpet backingsCleaning solvents DyesCarpet and other flooring Household cleaners

Wrinkle-resistant fabrics

GluesResinsInsulationFoamLaminatesPlastics/moldingsStiffenersWater repellents


• Caprolactam• 2-Ethyhexanoic acid• Formaldehyde• 1-Methyl-2-Pyrrolidinone• Naphthalene• Nonanal• Octanal• 4-PCH• Styrene• Toluene• Vinyl acetate

Carpet adhesives are tested separately. Fifteen identified chemicals are:

• Acetaldehyde• Benzothiazole• 2-Ethyl-1-hexanol• Formaldehyde• Isooctyacrylate• Methylbiphenyl• 1-Methyl-2-Pyrrolidinone• Naphthalene• Phenol• 4-PCH• Styrene• Toluene• Vinyl acetate• Vinyl cyclohexene• Xylenes (m,o,p)

Furniture also off-gasses volatile organic compounds and formaldehyde.Wood furniture is frequently made of plywood and particleboard made withurea-formaldehyde glue that emits high levels of formaldehyde when new.Phenol-formaldehyde and resorcinol are low emitters of formaldehyde. Solidwood is a nonemitter.

Polyurethane foam (e.g., seat cushions) is blown in by hydrofluorocar-bons that are being phased out. Alternative agents are isoproprene, acetone,


pentane, and carbon dioxide with limonene and terpene. Polyurethane is alsotreated with polybrominated diphenyl ethers (PBDEs)—a flame retardant.

Lamination requires solvent-based adhesives with high VOC emitters.Paints, stains, varnishes, shellacs, and lacquers emit VOCs. Allegedly, mostmanufacturers have converted to low emitter or no emissions paints and lac-quers. Oil-based paints, varnishes, shellacs, and lacquers are all high emit-ters of a barrage of VOC including methanol.

Sensory Irritation Testing in Environmental Chambers

Toxicological testing that is based on environmental chamber technol-ogy and animal inhalation studies are performed to address sensory irri-tation caused by airborne chemicals. Product emissions are introducedin a chamber housing laboratory animals. The breathing patterns andother clinical responses are then monitored. Challenges are singular ormultiple.

There have been isolated instances of human irritation testing using envi-ronmental chambers. For example, a researcher who has received consider-able attention internationally used chamber challenge testing to develop adose response relationship for discomfort due to volatile organic compounds.See Table 13.3 for a summary of his findings.

There have been attempts by some researchers to perform challenge test-ing without the benefit of a chamber or known, monitored levels of expo-sure. Yet as the chemical exposure levels are poorly controlled, the resultsare questionable. There is also concern for life-threatening patient reactionsthat could result in medical emergencies. For these reasons, human chal-lenge testing is rare in the United States.

TABLE 13.3

Summary of Research Findings on Effectsof Total Volatile Organic Compound(TVOC) Mixtures6

TVOC (mg/m3) Health Effects/Irritancy Response

<0.20 No response0.20–3.0 Irritation and discomfort3.0-25 Discomfort (probable headache)>25 Neurotoxic/health effects


Product Collection

In the United States, there are no hard, fast mandates for product emissionssampling. Green Seal covers cleaning fluids. Green Label covers carpets andcarpet pads. The GREENGUARD Environmental Institute, an AmericanNational Standards Institute (ANSI) accredited standards developer, pub-lished its standards and testing methodologies in 2002 for a variety of con-struction materials and furnishings. In 2010, the GREEN Building Initiative(GREEN Globes) published the first ANSI accredited green building ratingsystem with established emissions testing protocols. ANSI/American Societyof Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) 189.1,“Standard for the Design of High Performance Green Buildings” (ASHRAEStandard) was published in 2010, covering products and air emissions inoffice buildings and institutions. The GREEN Building Standard as pub-lished by the National Home Builders Association covers standards for resi-dential construction.

Within the ASHRAE Standard, the project committee defered to CaliforniaSpecification 01350 (“Specification”) for protocols to perform materials emis-sions testing of building components and contents. The Specification istitled “Standard Practice for the Testing of Volatile Organic Emissions fromVarious Sources Using Small-Scale Environmental Chambers,” and theSpecification is “generally consistent with the (2002) European Committeefor Standardizations PrEN13419-3.”7 Introductory comments in the SampleCollection Section include the following:8

• If the sampling is done improperly, the sample is in error and anysubsequent analysis is invalid.

• Samples shall be representative of the product manufactured andproduced under typical operating conditions.

• Special care shall be taken to prevent contamination of the prod-uct sample from any external sources (e.g., solvent-containingproducts such as stored paint) prior to, during, and after samplecollection.

• Samples must be stored immediately after collection in airtight,moisture-proof containers/packaging to prevent contamination andto preserve their chemical integrity by preventing subsequent VOCemission losses.

• Sampling location/site shall be selected to allow for reproducible,easy access to representative cross-sections of the product category.

With the exception of containerized products, samples shall be collected andshipped from the manufacturing facility within one week of the actual pro-duction completion date.


The California Specification is for collection and analysis of newly manufac-tured building materials only (see Table 13.4) and not entire components (e.g.,office partitions and desks). There are also limited laboratories in the UnitedStates that have environmental chambers for emissions testing on larger items.

GREENGUARD Environmental Institute is one such laboratory—withconsiderable expertise in certifying manufacturer products and in testinglarge item single- or multiple-purchase consumer products. Their samplecollection procedures are similar to those of the California Specificationswith but a few additions—items that are not otherwise included. Thus thesample collection approach for the office equipment, large furnishings, andelectronic equipment is expanded upon in Table 13.5.

TABLE 13.4

Sample Collection Procedures as Recommended by California Specification 01250

Group Material Type Sample Collection Procedure

Tile, strip, panel, and plank VCT, resilient floor tile, linoleum tile, wood floor strips,(less than 2 feet wide) parquet flooring, laminated flooring, modular carpet tile

1. Collected directly off the packing line2. Minimum of four representative tiles, strips, or planks—

minimum 64 square inch total (e.g., four 4 inch × 4 inchpieces)

3. Stack and pack in two layers of heavy-duty aluminum foil(seal with clear packaging tape)

4. Label and place foil wrapped samples in polyethylene orMylar bag

5. Seal bag with tie wrap6. No more than 1 hour between collection and packing

Sheet and roll goods broadloom carpet, sheet vinyl, sheet linoleum, carpet cushion,(greater than 2 feet wide) wall coverings, other fabric

1. Collected within 24 hours of productions directly from endof the product roll.

2. Minimum of 2 yards or two full circumferences from the endof the roll

3. A 1 foot wide strip of material shall be cut across the widthof the roll, at least 1 foot discarded from each end of thestrip—minimum of four 1 foot × 1 foot squares

4. Wall coverings and other fabrics may be collected as a full orpartial production roll with minimum of 10 layers of wrap

5. Stack and pack in two layers of heavy-duty aluminum foil(seal with clear packaging tape)

6. Label and place foil wrapped samples in polyethylene orMylar bag

7. Seal bag with tie wrap8. No more than 1 hour between collection and packing

(continued)


Beyond “dynamic environmental chamber” emissions testing, many ofthe larger environmental/industrial hygiene laboratories perform smallscale, headspace sampling of some of the smaller building components.As laboratories may vary from the California Specifications and GreenEnvironmental Institute Procedures in their headspace protocols, consult

TABLE 13.4 (CONTINUED)

Sample Collection Procedures as Recommended by California Specification 01250


Rigid panel products(greater than 2 feet wide)

gypsum board, other wall paneling, insulation board, orientedstrand board (OSB), medium density fiberboard (MDF),plywood, particleboard, etc.1. Collected within 24 hours of productions directly from end

of the product roll2. Select a panel at least 3 panels down from the top of the stack

3. For large panel products, the sample shall be taken at least6 inches away from all edges of a panel.

4. Cut panel into four 1 foot × 1 foot pieces5. Stack and pack in two layers of heavy-duty aluminum foil

(seal with clear packaging tape)6. Label and place foil wrapped samples in polyethylene or

Mylar bag7. Seal bag with tie wrap8. No more than 1 hour between collection and packing

Fiberglass insulation battproducts

1. Collected directly off the packing line2. Cut four 2 foot long sections across the width of the batt3. Stack, compress, and pack in two layers of heavy-duty

aluminum foil (seal with clear packaging tape)4. Label and place foil wrapped samples in polyethylene or Mylar

bag5. Seal bag with tie wrap6. No more than 1 hour between collection and packing

Containerized products adhesives, sealants, paints, other coatings, primers, and other“wet” products1. Paints, other coatings and primers can be supplied in

original, standard, 1-quart or 1-gallon consumer containers2. If less than 1 gallon consumer packaging, adhesives can be

supplied in their consumer containers (e.g., applicator tubeor can)

3. If greater than 1 gallon packaging, adhesives can becollected in clean, unused paint 1-pint or 1-quart size cans.They should be filled to eliminate headspace, and thecollection method should be documented

4. Affix MSDS, specification sheet for the product, sample labelwith manufacturer and sample ID, date and time of samplecollection


TABLE 13.5

Sample Collection Procedures as Recommended by GREENGUARDEnvironmental Institute


Tile, strip, panel, and plank Similar to Table 13.4Sheet and roll goods Similar to Table 13.4Rigid panel products Similar to Table 13.4Hardcopy devices printers, multifunctional machines, fax machines, and copiers

1. Select products representative of similar products by themanufacturer

2. The product shall not be treated differently from others3. The product may be a prototype—identical to the latter

serial product4. Product shall be packaged using the manufacturer’s

standard packing5. Enclose sample details—sample ID, manufacturer, machine

name, machine type, test mode(s), filter, device number(Serial #), toner/cartridge numbers, paper used (type andsize), date manufactured

6. If not from factory, consult with testing laboratory7. Fill out laboratory chain of custody

Containerized products Similar to Table 13.4Insulation fiberglass batting, board and rigid foam, blowing wools and

loose fill, spray foam insulation1. Fiberglass batting collection similar to that of Table 13.42. Boards and rigid foam boxed at the factory should be

allowed to condition for 15 minutes. Manufacturers whowish to provide Greenguard Certified products for furniturepanel applications will be expected to deliver product forthe purposes of emissions testing in the same fashion asstandard board products (more details available byGREENGUARD laboratory)

3. Blowing wools and loose fill should be collected from thecompressed or evacuated product package 15 minutesfollowing packaging. Loose fill insulation shall be placed ina specialized packaging bag, fill about 66% to 75% of the bag

4. Spray foam insulation (closed cell foam)—spray 1 foot × 1foot sample thickness, based on stud size (e.g., 3.5 inch or5.5 inch) with one or two passes, 1.5 to 2 inch thick. Wait1 hour and place in Mylar bag

5. Spray foam insulation (open cell foam)—spray 1 foot × 1foot sample to thickness of 3.5 feet to 4 inches for walls and6 inches for attics. Scarf the sample of excess foam. Wait 24hours and place in Mylar bag

Furniture and other largeproducts

1. Furniture and other large products shall be collectedimmediately following manufacturing and packed inaccordance with manufacturer’s standard packing practices(e.g., shrink wrap and cardboard box). For more details,consult with testing laboratory


with the laboratory of choice as to their recommended practices for sam-ple collection.

Environmental Chamber and Analytical Methodology9,10,11,12,13

Environmental chamber testing is quantitative and qualitative for project-ing product emissions in indoor environments. In the United States, themost frequently referenced protocols for chamber testing are the AmericanSociety for Testing and Materials (ASTM) published “Standard Guide forSmall-Scale Environmental Chamber Determinations of Organic Emissionsfrom Indoor Materials” (ASTM D5116) and “Standard Practices for Full-Scale Chamber Determination of Volatile Organic Emissions from IndoorMaterials/Products” (ASTM D6670). The most comprehensive testing meth-odology incorporating these principles for small and large scale chambersis available from the GREENGUARD Environmental Institute, “StandardMethod for Measuring and Evaluating Chemical Emissions from BuildingMaterials, Finishes and Furnishings Using Dynamic EnvironmentalChambers.” This methodology incorporates the principles of CaliforniaSpecification 1350 but is extended to additional products including officefurniture. Chamber designs simulate indoor environments by artificiallycontrolling temperature, humidity, and air flow. The incoming air isstripped and cleaned of contaminants and air exchange rates established(e.g., two room changes per hour) in accordance with ASHRAE Standard 62.1recommendations.

After a defined preconditioning period (outside the chamber), materials/products (e.g., small samples or whole furnishing modules) are placed in ormaterial (e.g., paint) applied onto a surface inside a chamber. The chamberis closed, and the humidity, temperature, chamber air exchange rates, andair movement are maintained at a constant setting until such time as theassigned enclosure time has lapsed and all chamber air testing has beencompleted.

The prescribed period of time for material/product confinement is basedof product size and number of air samples required. Smaller, single sampleproducts may be completed within 24-hours (i.e., one day). Large, multiplesample products may take up 720 hours (i.e., one month). Thus the timerequired to complete an analysis (i.e., precondition time and chamber test-ing time) is one day to more than a month.

After background air testing and product loading, chamber air samples arecollected at intervals determined by the laboratory and product type beingtested. For example, initial, unspecified Greenguard Certification cham-ber air testing is performed 6 hours, 24 hours, 48 hours, 72 hours, 96 hours(or 120 hours), and 168 hours (i.e., one week). Electronic product chamber


testing is done within 30 minutes of loading and taken at 1.5 hours, 2.5 hours,4 hours, and 8 hours.

At the predesignated sample intervals, air samples are extracted directlyfrom the multiple ports in chamber exhaust. Chamber emissions air samplemedia and analytical methods are as follows:

• Total and identified volatile organic compounds—thermally des-orbed, solid-phase sorption tubes analyzed by TO-1 and TO-17

• Formaldehyde and other low molecular weight aldehydes—solidsorbent (e.g., silica gel) treated with an acid solution of 2,4-dini-trophenylhydrazine (DNPH) analyzed by high pressure liquidChromatography (HPLC)

• Phthalates—OVS Tenax analyzed by gas chromatography flameionization detector (GC/FID)

FIGURE 13.1Large scale emissions testing chamber—greater than 25 m3 volume, used for large products.(Courtesy of Air Quality Sciences, Inc., Marietta, Georgia)


• Ozone—direct reading UV absorbance based ozone analyzer• Dust—47 mm GF-50 glass filter analyzed by gravimetric

measurement• Respirable particles (P10)—direct reading laser photometer aerosol

monitor with less than 10 micron setting

The emissions air sample results (i.e., concentration in chamber), chamberair exchange rate, and ratio of product to chamber air volume (i.e., productloading) are used to calculate the emission factor—at any given point intime. For example, annual Greenguard Certification testing requires emis-sion factor determination at the end of 168 hours chamber time.

The emission factor is used to compare emission levels among products ata specific exposure time—in the chamber. The formula is as follows:

EF CNL

= ×

EF = Emission factor in µg/m2 • hour (surface area) or µg/unit • hour(product)

C = Concentration in chamber in µg/m3

N = Chamber air exchange rate (e.g., number of room changes/hour)L = Product loading in m2/m3 (surface area) or unit/m3 (product)

The concentrations in the chambers are neither a reflection nor a prediction ofanticipated exposure concentrations in indoor air environments. The “emissionrate” is calculated to predict exposure concentrations in buildings. Factors arecalculations based on chambers, and rates are calculations based on buildingenvironmental parameters.13 The preceding parameters include air movement,amount of makeup air, air volume of room(s), and level of occupant activity.

Where not performing annual Certification renewals (e.g., at the endof 168 days) or special single test requests after a given time period (e.g.,five-day special request), chamber air sampling has been performed initially,at intervals, and at the end of the chamber testing. The emission rates for

TABLE 13.6

Building Parameters for Office Buildings14

Parameter GG Office Model

Room length 10 ftRoom width 14 ftRoom height 8 ftRoom volume 32 m3

Air exchange rate 0.72 hr-1Number of units 1


each of the chemicals (sampled at various intervals) are compiled, and thechamber data for those products that do not have constant emission factorsis feed to a computer. “Predicted air concentrations” for specified indoor airenvironments (e.g., offices) are thus determined by computer modeling.

Measurements of Product Emission Factors

Emissions from a product are measured in terms micrograms (µg) of chemi-cal off-gassed from a solid product (e.g., foam), liquid (e.g., paint), or a com-posite unit (e.g., chair). Solid product emission factors/rates are based onexposed surface area(s) per hour [i.e., micrograms per square meters-hour(µg/m2-hour)]. Liquid is based on relative mass in an hour [i.e., microgramsper gram-hour (µg/g-hour)], and composite units are based on units in anhour [micrograms per composite-hour (µg/unit-hour)].

One study compares emission factors from office furnishings—chamberemissions. Findings were as follows:2

• Modular desks• Volatile organic compounds–160 to 45,000 mg/workstation-hour• Formaldehyde–802 to 3780 mg/workstation-hour

Chairs

• Volatile organic compounds–159 to 450 mg/chair-hour• Formaldehyde–no detection to 1670 mg/chair-hour

Tackable acoustical partitions (with phenol-formaldehyde treated fiber-glass insulation)

• Volatile organic compounds–0.006 to 0.074 mg/m2-hour• Formaldehyde–0.158 to 0.37 mg/m2-hour

In the above study, modular desks are the highest emitters of both VOCsand formaldehyde. Also of particular interest, acoustical partitions that weretreated with phenol-formaldehyde resins off-gassed considerably less form-aldehyde than urea-formaldehyde products (e.g., desks and chairs).

Another brief study reported emission factors for products used to buildfurniture. See Table 13.7. The chamber comparison of product emissions isinteresting in that even water-based adhesives off-gassed high levels of VOCs.Wood stains off-gassed more VOCs than polyurethane lacquer. Textiles mayoff-gas more formaldehyde than some wood products, and insulation did, atthe time of the study, off-gas formaldehyde.


A study involving formaldehyde emissions from finished wood productharbors a different focus, a different enlightenment in the world of strange,unforeseen consequences following water damage and finished/unfinishedwood products (see Table 13.8). Water damaged chipboard off-gases fourtimes more formaldehyde than nonwater damaged chipboard. Unfinishedwood products off-gas more formaldehyde than finished boards.


In the absence of U.S. federal standards for indoor air quality pollutants orproduct emissions limits, several programs are recognized as providingvoluntary guidelines and recommendations. These include the U.S. GreenBuilding Council’s LEED programs where office furniture is required to meetthe GREENGUARD criteria for office furniture as noted in Table 13.9, andall other products must meet the testing and chemical criteria as prescribed

TABLE 13.7

Reported Highest Emissions from ProductsUsed to Build Furniture2,15

ProductEmission Factor

(µg/m2-hour)

Volatile Organic Compounds

Solvent-based adhesives 17,000,000Water-based adhesives 2,100,000Furniture spray polish 300,000Wood stain 17,000Polyurethane lacquer 6,000Plywood 2,400Polystyrene foam 1,400Particleboard–fiberboard 150Hardboard 30Medium density fiberboard 40

FormaldehydeWood products 170–900Insulation 16–26Wall coverings 20–600Textiles 0–3,000

Note: Study is limited in scope therefore not to be con-sidered conclusive or all encompassing regard-ing all products. Variations will occur betweenproduct types, manufacturers, formulations, andproduction processes.


in California Specification 1350. The recent ANSI/ASHRAE 189.1 Standard,“Standard for the Design of High-Performance, Green Buildings—Except Low-Rise Residential Buildings,” provides a “limited list of acceptable emissions fac-tors” for office furniture systems and furniture components. The Standard onlyaddresses total VOCs, formaldehyde, total aldehydes, 4-PCH as in the LEEDprogram, but it has added 31 additional VOCs that are primarily VOCs withestablished California Chronic Reference Exposure Limits (CREL). This stan-dard is limited to high-performance (e.g., large office buildings). This is not tosay that the Standard cannot be applied to other situations, but, once again, it islimited. See Tables 13.9 and 13.10.

The ANSI/ASHRAE Standard frequently defers to the California “StandardPractice for Testing Volatile Organic Emissions from Various Sources UsingSmall-Scale Environmental Chambers.” The California limits are moreextensive and focused on the entire environment and maximum exposurelimits to building occupants in terms of Chronic Relative Exposure Limits(i.e., Chronic REL, CREL) as well as carpet emissions, based on the predictedair concentrations for each given chemical for a given environment (e.g., 2200square foot residence). Each product must not exceed 50 percent of the CRELfor each chemical listed, and the composite of all products in a given indoorenvironment must not exceed the actual CREL.

TABLE 13.8

Highest Formaldehyde Emissions from FinishedWood Products2

MaterialConcentrations

(µg/m3)

Unfinished medium density fiberboard (MDF) 970Unfinished particleboard 809Finished particleboard 719Finished MDF 246Water-damaged chipboard 48Nonwater damaged chipboard 10

TABLE 13.9

Workstation Systems and Seating Office EmissionsConcentration Limits

Chemical Contaminant

Workstation Emission Limits

Seating Emission Limits

TVOC 0.5 µg/m3 0.25 µg/m3

Formaldehyde 50 ppb 25 ppbTotal aldehydes 100 ppb 50 ppb4-PCH 0.0065 mg/m3 0.00325 mg/m3


TABLE 13.10

Individual VOC Allowable Concentrations/Emission Factors for OfficeFurniture Systems

Chemical

Workstation Maximum Allowable

Concentration µg/m3

Seating Maximum Allowable

Concentration µg/m3

Open Plan Maximum Allowable Emission

Factor µg/m2-h

Private Office

Maximum Allowable Emission

Factor µg/m2-h

California CREL µg/m3

1,1,1-trichloromethane(methyl chloroform)

500 250 345 696 1000

1,4-dichlorobenzene 400 200 278 557 8001,4-dioxane 1500 750 1034 2,089 30001-methoxy-2-propanol(propylene glycolmonoethyl ether)

3500 1750 2413 4874 7000

1-methyl-2-pyrrolidinone 160 80 110 223 –2-ethoxyethanol 35 17.5 24 4.9 702-ethoxyethyl acetate 150 75 103 209 3002-methoxyethanol 30 15 21 42 90acetaldehyde 9 4.5 6 13 140benzene 30 15 21 42 60carbon dixulfide 400 200 276 557 800chlorinated dioxins &dibenzofurans

– – – – 0.0004

chlorobenzene 500 250 345 696 1000chloroform 150 75 103 209 300dimethyl formamide, N,N- 40 20 28 56 80epichlorohydrin 1.5 0.75 1 2.1 3ethylbenzene 1000 500 689 1392 2000ethylene glycol 200 100 138 278 400formaldehyde 16.5 8.25 11 23 9gluteraldehyde – – – – 0.08hexane (n-) 3500 1750 2413 4874 7000isopropanol 3500 1750 2413 4874 7000methylene chloride 200 100 138 278 400monomethyl ether acetate 45 22.5 31 63 60naphthalene 4.5 2.25 3 6 9phenol 100 50 68.9 139 200styrene 450 225 320 627 900tetrachloroethylene 17.5 8.75 12.1 24.4 35toluene 150 75 103 209 300trichloroethylene 300 150 207 418 600vinyl acetate 100 50 68.9 139 200xylene (m,o,p) 350 175 241 487 700


The Chronic REL is intended to protect those who are both healthy andthose who are environmentally sensitive to chemicals 24 hours a day formore than 10 years. A few of the more than 90 substances with assignedChronic RELs can be found on Table 13.11 in association with the 31 chemicalslisted by the ANSI/ASHRAE Standard. This approach addresses residentialbuildings, small businesses, and schools as well as all office buildings. Asfor off-gassing chemicals from carpeting, California has set forth limits thatallegedly exceed that of the Green Label Plus limits. See Table 13.11.

GREENGUARD Environmental Institute has taken the California proto-cols and limits and expanded on them. GREENGUARD has deferred to theCalifornia CRELs and included all the more than 400 substances listed onthe ACGIH list of toxic chemicals. For substances not listed with a CREL,GREENGUARD guidelines uses 1/100th the ACGIH occupational exposurestandards as limits in the predicted air concentrations for the designatedindoor air environment.

However, GREENGUARD varies slightly from the others in providingmaximum allowable “long-term” emissions limits for phthalates, respirableparticles, and ozone (see Table 13.12).

GREENGUARD certifies Green Label carpeting/pads and Blue Angel elec-tronics equipment and copy/printer machines.

Summary

Going green is going lean! As man spends 90 percent or more of his timeindoors and buildings become more energy efficient, humanity is underassault from a multitude of chemicals. The response is to minimize expo-sures by the proactive approach of product emissions testing. Chamber

TABLE 13.11

California Chamber Emissions Testing Limits for Carpeting

Full 14-Day Emissions Chamber Test Additional 24 Hours and Annually

caprolactam—100 µg/m3 caprolactam—70 µg/m3

2-ethylhexoic acid—25 µg/m3 2-ethylhexoic acid—25 µg/m3

1-methyl-2-pyrrolidinone—160 µg/m3 1-methyl-2-pyrrolidinone—NA

nonanal—13 µg/m3 nonanal—13 µg/m3

octanal—7.2 µg/m3 octanal—7.2 µg/m3

3-phenylcyclohexene—2.5 µg/m3 3-phenylcyclohexene—2.5 µg/m3

styrene—220 µg/m3 styrene—220 µg/m3

acetaldehyde—4.5 µg/m3

benzene—30 µg/m3

formaldehyde—16 µg/m3

toluene—150 µg/m3

224 IndoorAirQuality:TheLatestSamplingofAnalyticalMethodsTA

BLE

13.

12

Gre

engu

ard

Max

imu

mA

llow

able

Em

issi

ons

Tota

l V

OC

a (µ

g/m

3 )

Ind

ivid

ual

V

OC

TLV

(mg/

m3 )

Form

ald

ehyd

eTo

tal

Ald

ehyd

esTo

tal

Ph

thal

ates

Par

ticu

late

s m

g/m

3

Ozo

ne

(pp

m)

Bui

ldin

gM

ater

ials

,Fur

nish

ings

,an

d F

inis

hes

Gre

engu

ard

Cer

tific

atio

nSc

hool

s:G

reen

guar

dan

dC

alif

orni

a–5

001/

100

TLV

25pp

b50

ppb

resp

irab

le—

0.05

Stan

dar

d–

½C

AC

hron

ic R

EL13

.5pp

bb–

––

–Sc

hool

s:G

reen

guar

dO

nly

250

1/10

0T

LV13

.5pp

b43

ppb

0.01

mg/

m3

resp

irab

le—

0.02

–E

lect

roni

csG

reen

guar

dsh

ortt

erm

(acu

te)

51/

10ST

EL

/C

c0.

04pp

m–

––

–lo

ngte

rm(c

hron

ic)

0.22

1/10

0T

LVd

0.01

3pp

m–

0.01

mg/

m3

resp

irab

le—

0.03

50.

05O

ffice

Equ

ipm

ent

Gre

engu

ard

and

Blu

eA

ngel

Mon

ochr

ome

0.4

Ben

zene

—0.

002

––

–to

tal—

0.16

0.03

Styr

ene—

0.04

Col

or0.

22B

enze

ne—

0.00

2–

––

tota

l—0.

160.

03pp

mSt

yren

e—0.

08G

reen

guar

dO

nly

Mon

ochr

ome

0.4

Ben

zene

—0.

002

0.05

mg/

m3

––

tota

l—0.

160.

03pp

mSt

yren

e—0.

04re

spir

able

—0.

015

1/10

TLV

Col

or0.

22B

enze

ne—

0.00

20.

05m

g/m

3–

–to

tal—

0.16

0.03

ppm

Styr

ene—

0.08

resp

irab

le—

0.01

51/

10T

LV

Not

e:R

espi

rabl

e=

PM10

;min

imum

seve

nd

ays

wit

hno

prec

ond

itio

ning

.a

Defi

ned

tobe

the

tota

lres

pons

eof

mea

sure

dV

OC

sfa

lling

wit

hin

the

C5–

C18

rang

e,w

ith

resp

onse

sca

libra

ted

toa

tolu

ene

surr

ogat

e.b

The

Cal

ifor

nia

Chr

onic

RE

Lfo

rfo

rmal

deh

yde

is9

ppb.

cL

ess

than

1/10

STE

L/

Cco

rres

pond

ing

toth

eA

CG

IHT

LVan

dA

IHA

WE

EL

(or

less

than

the

TW

Aif

noST

EL

/C

).d

Les

sth

an1/

100

the

TW

Aco

rres

pond

ing

toth

eA

CG

IHT

LVan

dA

IHA

WE

EL

.


testing methods are being refined, and the maximum acceptable limits seemto be in a constant state of motion.

The end game is, through computer modeling, to predict exposures toindoor air environments, whereby many of the “sick building syndrome”complaints can be better managed upfront. The cost can be hefty for the cer-tifications and special emissions chamber testing of furnishings, but the costat the other end can be occupant dissatisfaction, extensive environmentalconsultant costs, and low morale.

Predicted air concentrations are based on ideal air movement and exchangerates in office environments. Ideal is often disconnected from reality. Proceedwith a healthy dose of reserved skepticism!

References

1. Global Ecolabelling Network. What is Ecolabelling? (2008). Viewed on March 26,2010, at http://www.globallabelling.net/whatis.html

2. Franke, D., et al. Furnishings and the Indoor Environment. Air Quality Sciences,Inc., Atlanta, Georgia (1995).

3. Haneke, K.E. Review of Toxicological Literature—4Phenylcyclohexene. ResearchTriangle Park, North Carolina (July 2002).

4. Schleibinger, H., K. Fitzner, et al. Chemical analysis and sensory evaluationof indoor air by a thermal desportion/GC/FID/sniffer method. Gefahrstoffe Reinhalt Luft. 61:11–12 (2001), pp. 528–531.

5. Schleibinger, H., K. Fitzner, et al. VOC-concentrations in Berlin indoor envi-ronments between 1988 and 1999. Gefahrstoffe Reinhalt Luft. 61:1–2 (2001), pp.26–38.

6. Molhave, L. Irritancy of Volatile Organic Compounds in Indoor Air Quality. Paperpresented at the Fifth International Conference on Indoor Air Quality andClimate in Toronto, Canada (1990).

7. California Department of Health Services. Standard Practice for the Testing ofVolatileOrganicEmissionsfromVariousSourcesUsingSmall-ScaleEnvironmentalChambers (July 15, 2004).

8. Ibid., p. 14.9. American Standard and Testing Materials. Standard Guide for SmallScale

Environmental Chamber Determinations of Organic Emissions from Indoor Materials/Products. ASTM D5116-90 (1990).

10. Air Quality Sciences. Standard Method for Measuring and Evaluating Chemical Emissions from Building Materials, Finishes and Furnishings Using Dynamic Environmental Chambers. GREENGUARD Environmental Institute, Marietta,Georgia (2008).

11. Air Quality Sciences. Standard Method for Measuring and Evaluating Chemical and Particle Emissions from Office Equipment (Hardcopy Devices) Using Dynamic Environmental Chambers. GREENGUARD Environmental Institute, Marietta,Georgia (2009).


12. Air Quality Sciences. Standard Method for Measuring and Evaluating Chemical and Particle Emissions from Electronic Equipment Using Dynamic Environmental Chambers. GREENGUARD Environmental Institute, Marietta, Georgia (2009).

13. Air Quality Sciences. Defining Product Emission Measurements (Bulletin). AirQuality Sciences, Inc., Atlanta, Georgia (1995).

14. Air Quality Sciences. Standard Method for Measuring and Evaluating Chemical Emissions from Building Materials, Finishes and Furnishings Using Dynamic Environmental Chambers—Table 6.4 Parameters to Be Used for Calculation of VOC Concentrations. GREENGUARD Environmental Institute, Marietta, Georgia(2008), p. 48.

15. Black, M., D. Franke, and C. Northeim. Furnishings and the Indoor Environment.Journal of the Textile Institute (1994), pp. 496–504.

Section IV

Identification of Dusts

229

14ForensicsofDust

Since as early as the late 1800s, scientists have used forensic nucroscopyin crime detection. Pollen typing has been used to determine the sourceareas for illegal shipments of marijuana. Crime scene soil samples havebeen used to locate the source of the material. Clothing fibers are traced byfiber type and special dyes. Hair can be differentiated as to species (e.g.,human, dog, or cat) and distinct color, texture, and thickness. Dust found ata crime scene sometimes contains evidence as to an association with certainindustrial activities.

Only recently has forensic microscopy been recognized as a tool in indoorair quality investigations. Without forensic microscopy, identification ofunknowns was limited. The investigator would develop a theory as to thedust component that caused health problems and test the theory. Not onlywas this time-consuming and expensive, but the actual causative agent wasoften overlooked.

If building occupants complained of allergy symptoms, an investigatorautomatically assumed the problem was molds. Even when sample resultsdid not support the theory, the investigator may persist and state that thesampling methods are faulty. This scenario often culminates in an exten-sive search for the ubiquitous mold and, in many cases, destruction of wallsand flooring in the frantic search for the hidden demon. If one looks hardenough, behind enough walls and enclosures, an investigator will eventu-ally locate molds.

With forensic microscopy, the allergenic dust in an occupied space can becharacterized. Not only can pollen, mold spores, algae, and insect parts beidentified, but an experienced microscopist can characterize rodent, bat, cat,and dog hairs as well. The microscopist can also quantify the populationdensity as normal or excessive. For instance, the microscopist may identifyexcessive amounts of rodent hairs. When pressed for more information, themicroscopist may come back with, “More than normally observed in occu-pied spaces, typical of rodent infested barns.”

Forensic microscopy has also been used to identify other components ofdust that may cause nonallergy health problems. For instance, chemicalsadsorbed onto the surface of particles may be identified (e.g., formaldehydeon dust particles). Pharmaceutical dust can be identified from previousmanufacturing facilities (e.g., amphetamines). Fibers that may cause lungirritation (e.g., treated glass fibers) or long-term health effects (e.g., asbestos)


can be identified. Toxic minerals (e.g., silica) and paint components (e.g., leadchromate and fungicides) can be identified.

Suspect materials may be either confirmed or denied. For instance, in onecase, white spots on surfaces implicated paint as the source of indoor airquality, yet the spots were silicon.

Forensic microscopy can be used as a tool in identifying particles andchemicals. The list goes on!

Occurrences of Forensic Dust

In 1972, The McCrone Institute performed a study to determine settling ratesof dust on surfaces. They found that nearly 1,000 particles per one squarecentimeter settled hourly. The particles were all in excess of 5 microns in size.The calculated settling rate for dust was thus found to be 24,000 particles persquare centimeter per day. Typical dust in indoor air quality was also foundto consist of human epidermal cells, plant pollen, human/animal hairs,textile fibers, paper fibers, minerals (from outdoor soils and dust broughtindoors), and a host of other materials that may typify a given environment(e.g., fly ash from the gas burning furnace in the building).1

A study by Cornell University suggested that indoor air quality problemswere caused by glass fibers.2 Possible sources of airborne glass fiber expo-sures include, but are not limited to, fireproofing in air plenums, ceiling tiles,duct board, and furnace filter material. For a few photographic examples ofdifferent source glass fibers, see Figure 14.1.

One example of glass fibers in indoor air quality involves a residential occu-pant. A woman complained of a home-related itch. Her doctor speculatedthe probable cause was glass fibers. Subsequently, settled dust samples werecollected from various areas around the house, and bulk samples were takenof various building/furnishing materials known to have fibers. Each of thesettled dust samples was found to contain large amounts of glass fibers thatwere impregnated and covered with globules of a pink resin. None of the bulkglass fiber samples matched. The investigator returned for additional samplesand tracked down insulation (e.g., batting) in the enclosed wall spaces thathad the same appearance as the settled fibers in the dust. Thus, the insulationwas the confirmed culprit. Upon further investigation, the means by whichthe enclosed insulation entered into the occupied space was determined. Theair movement caused by leaking air ducts disturbed the surface of the inte-rior insulation and picked up the fibers, distributing them throughout theresidence through the air supply vents.

Some people say they are allergic to dust, but dust varies in composition.There is a considerable difference between barnyard dust verses dust in aconditioned building. It is the composition that causes health problems, not

ForensicsofDust 231

the dust itself. For a generalized listing of dust components and some repre-sentative photomicrographs, see Table 14.1 and Figure 14.2.

It should also be noted that dust composition is in a constant state of flux,even in conditioned office spaces where there are no internal sources ofdust (e.g., molds growing, cockroaches, and rodents). People bring in dust

FIGURE 14.1Photomicrographs of glass fibers from different sources, magnified 400x. They include: (topleft) untreated fiberglass; (top right) duct board; (bottom left) duct board with coating materialtreated using xylene and sulfuric acid to affect a color change that tags free aldehydes; and(bottom right) thermal insulation with asphalt impregnated binder.


on their clothing, shoes, and body surfaces. They bring components of dustfrom the environments they live, shop, and play in. Yet it is unreasonablenot to anticipate internal sources as well. With consideration for all possiblesources, one dust sample may have several allergens and other componentsthat may cause nonallergen health problems. Thus an investigator should beopen to all possibilities.

Sampling Methodologies5, 6

Although there are a few published approaches, most procedures shouldbe worked out between the analytical laboratory and the indoor air qualityinvestigator. Yet keep in mind, methods appear simple but if not completely

TABLE 14.1

Characterization of Dust Components in IndoorEnvironments

Biological

PollenFungal and bacterial sporesAlgaeInsect partsSkin cells

Fibers

Hair (e.g., human, cat, or dog hair)Clothes fibersPaper fibersSpun fibers (e.g., glass fibers)Mineral fibers (e.g., asbestos)Wood (hardwood versus soft wood)Plant fibers (e.g., seed hairs, blast/leaf/grass fibers)Miscellaneous (e.g., carbon fibers, feathers, spider webs, etc.)

Minerals

SoilsAmorphous versus crystalline

Others

Soot and ashMetal fumesPaintExplosivesPharmaceuticalsDrugs

Source: Excerpted from Forensic Microscopy4

ForensicsofDust 233

thought out, these simple methodologies can be misconstrued or misinter-pretation. Plan a strategy and stick to it. If disallowed access, don’t take asample just to take a sample.

For example, an investigator was attempting to recreate dust exposuresthat occurred two years prior to sample collection. This was a litigious casewhereby the defense attorneys would only allow the investigator to take

FIGURE 14.2Photomicrographs of identified dust component, magnified 400x. They are epithelial cells (topleft), an insect leg (top right), hair fibers (middle left), clothing fibers (middle right), crystallinemineral formations (bottom left), and a general overview of environmental dust (bottom right).The latter shows minerals, spores, wood fibers, pollen, and plant hair.


carpet and dust samples from under old filing cabinets. The defense attor-neys refused to permit dust collection from above ceiling tiles. So the inves-tigator took samples from locations where he was permitted to sample (e.g.,under the filing cabinet). The forensic samples predictably disclosed mini-mal dust. In this situation, the investigator wasted time and money samplingonly where he was permitted access, not where good judgment dictated thatthe sample be taken.

Consider when and where the sample should be taken. For historic sur-face dust that has settled over an extended period of time, the investigatorshould consider areas that frequently get overlooked during cleaning (e.g.,ledges above doors, window frames, picture frames, above ceiling tiles, andair supply/return vents). Carpets and upholstery generally retain dust overthe passage of years, and if a picture of the past is required, such as in litiga-tion, dust from under the carpet (e.g., bulk sample) or within the upholstery(e.g., micro-vacuum sample) should be collected.

For a more recent settled dust sample, the investigator may want to deter-mine the last time an area was cleaned, record the date/time, and take asample in an area that has been cleaned. If an area has not been confirmed ashaving been cleaned, assume it has not. Areas that typically get missed aretops of computers, bookshelves, lamps, and memorabilia.

For airborne dust, the investigator has several means for taking air sam-ples. Air samples would represent dust components and levels that the occu-pant was breathing during the sampling period.

Methods herein are provided for settled surface dust sampling, airbornedust sampling, bulk sampling, and textile/carpet sampling. Choose themethod that is most appropriate to a given situation.

Settled Surface Dust Sampling

Settled dust may be collected from smooth surfaces (e.g., desktops) andrough surfaces (e.g., carpeting) by any number of techniques. Some requirespecialty supplies. Others require the use of that which is readily availableat a local retail store.

Specialty Tape

Specialty tape may be purchased from microscope supply venders. Thetacky material is minimal and does not hold the collected material such thatit becomes difficult or impossible to remove. The taped material is retainedby affixing the tacky surface to a clean surface and placing it into a fiber freeenvelope/plastic bag for transport to the laboratory. At the laboratory, themicroscopist will “pluck” the material from the surface of the tape by usinga special micromanipulation device (e.g., fine tungsten needles with a tipmeasuring 1 to 10 microns in diameter). With this technique, the dust com-ponents may be isolated and identified individually.

ForensicsofDust 235

Clear Tape

A clear tape (e.g., 3M Crystal Clear) is available in some office supply stores.This tape is not the usual tape that one can see through when it is affixedto paper. It is a clear tape where the writing on the carrier is readable. Thetape is touched to a surface, and dust particles adhere to the sticky portionof the tape. This is then placed immediately onto a microscope slide with orwithout a stain.

The drawback to this method is that once affixed to the slide, the collectedsample cannot be further manipulated and stained without great difficulty(e.g., treating the surface of the tape with a solvent). Then, too, if there isexcessive material on the tape to reasonably distinguish individual particles,the sample may again require special processing. With these limitations inmind, the environmental professional may choose to use this technique onlyfor screening and gross examination of material or for confirming the pres-ence of a suspect material for which the microscope slide has already beentreated with the appropriate stain.

However, if the investigator should choose to use the clear tape, there aremeans available to manage the otherwise irretrievable sample. The particlesthat have adhered to the tape may be removed by lifting the tape, applyinga small drop of benzene, and using a fine needle to make a small ball ofthe adhesive trapped particle(s).6 The trapped material can be withdrawnand the ball of adhesive removed chemically. This process is tedious andchoice of a more easily manipulated collection media is desired wheneverfeasible.

Post-it Paper7

Post-it paper is excellent for sample collection as it is easily obtained andinexpensive. The sticky surface of a Post-it is pressed onto the settled dust,the paper folded into itself (with the sticky portion inside), and shipped tothe laboratory of choice in a plastic zip-lock bag. Analysis may be performedby particle picking material from the sticky surface or by scanning electronmicroscope while the particles are still on the paper.

Micro-vacuuming8

Micro-vacuuming has been receiving a considerable amount of attention,particularly for asbestos contaminated settled dust. A vacuum pump is usedto collect dust particulate within a 100 square centimeter surface at a recom-mended flow rate of 2.0 liters per minute. This method is particularly usefulin dust collection from irregular surfaces (e.g., carpeting).

The detection limit of this methodology is 150,000 structures per squarefoot [or 161 structures per square centimeter (structures/sq cm)] as deter-mined by transmission electron microscopy (TEM). Concentrations over


1,000 structures/sq cm are considered elevated, while levels over 100,000were used to indicate an abatement project barrier has been breached. Thereare no regulations that provide acceptable/nonacceptable limits.

Airborne Dust Sampling

Airborne dust capture may be preferred over settled dust collection in order todetermine the existing suspended particulates (not the existing and previouslydeposited) and to collect some of the smaller particles that may not have settleddue to the size or shape. For example, particles less than 2.5 microns (e.g., PM 2.5)would tend not to settle and would best be collected through air sampling.

Spore Trap

A spore trap consists of a treated microscope slide that is contained within acassette. The slide is treated with a sticky substance onto which mold spores,pollen, insect parts and pieces, skin fragments, hairs, and fibers will adhereupon impaction onto its surface. Its most common use has been sampling fornonviable mold spores, mold fragments, and pollen.

The end seals on the cassette are removed, and the cassette is connectedby flexible tubing and a 1/2-inch to 1/4-inch converter to an air samplingpump. The pump flow rate is calibrated. Air is sampled for an abbreviatedperiod of time, cassettes are resealed, and samples are sent to a laboratoryfor analysis.

A summary approach is as follows:

• Equipment: air sampling pump• Collection medium: Air-O-Cell cassette• Flow rate: 15 liters/minute• Recommended sample duration: 1 to 10 minutes, based on antici-

pated loading

Collection medium loading is based on perceived environmental conditionsand anticipated airborne spores, based on professional experience. Whereexcessive loading occurs on the slide, enumeration becomes difficult if notimpossible. In the latter case, samples may be significantly underestimatedand difficult to identify.

In clean office environments and outside where there is very little dustanticipated, sampling should be performed for 10 minutes. In dusty areasand areas where there is considerable renovation, a 1 minute sampleshould be considered. Indoor air environments where there is moder-ate dust or where considerable levels of mold spores (e.g., greater than500 spores) are anticipated, the sampling duration should be reduced

ForensicsofDust 237

accordingly (e.g., 6 to 8 minutes). Experience will be the investigators bestguide.

Membrane Filters

Air sampling may be performed for suspended dust by using a membranefilter that is contained within a cassette and an air sampling pump. This isa dry sampling method and will desiccate, damage the more fragile compo-nents in dust.


• Equipment: air sampling pump• Collection media: cassette containing a filter• Flow rate: 1 to 15 liters/minute• Recommended sample duration: 100 minutes (i.e., fragile biologicals),

135 minutes (i.e., high flow rate collection of nonfragile material) to2000 minutes (i.e., low flow rate of nonfragile material)

• Recommended air volume: 100 to 2000 liters

Recommended filter types include, but are not limited to, the following:

• Polycarbonate filter—Using a stereomicroscope, the microscopistmay selectively isolate and pluck material from the surface of thefilter.

• Fiberglass filter—The microscopist may slice the filter and look atthe material through an unspecialized microscope (e.g., not a phasecontrast microscope) that will allow a view of the material on thesurface of the fiberglass while the light passes through the thinned-out fibrous backing.

• Mixed cellulose ester filter—The microscopist may melt the filter(in a procedure similar to that of asbestos air sample filter analysis)using vaporized acetone. This method is not recommended in mostcases where desiccation or destruction of the sought after materialmay occur. If the material is an unknown, this approach will disal-low identification of content.

Keep in mind that each of the above filters has different pore sizes, depend-ing upon the manufacturer and the various specifications. One filter typemay come with several choices as to pore size or particle retention capa-bilities. The smaller the pore size, the more expensive the filter. Be certainto obtain one that will capture particulates down to 1 micron in diameter orbetter. All of the above-mentioned filters can be purchased with a minimumof 1 micron and down to better than 0.025 microns.8 If electron microscopy isto be performed, the latter is unnecessary.


The air sampling flow rate should be adjusted to produce as large a samplevolume as possible within the time period desired while keeping the upperlimit within a flow that will not cause damage to the filter or desiccate bio-logical material (e.g., mold spores and bacteria). Although 15 liters per min-ute will not damage most filters, a flow rate of 1 liter per minute or less is notlikely to dry biological components in airborne dust.

Larger air volumes provide more representative samples. Although totalsampled air volumes have been as low as 100 liters, a collection of 2000 litersmay prove more valuable. Then, too, the biological material stands a greaterchance of being damaged with longer sample durations. So the environ-mental professional may choose to take a minimum of two samples persite where he/she suspects airborne biological dust. A low flow, low samplevolume will allow collection of the more fragile biological components, anda high flow, high volume will permit greater detection. If components of thehigh volume sample fail to reflect biological components of the low volumesample, the high flow, high volume sample is likely to have caused dam-age to the more fragile biological component. Otherwise, a high flow, highvolume sample provides more sample material. A dump truck of sample isbetter than a thimble!

Even if the microscopist is not intending to quantify the results in particleper cubic meter, air volumes should be recorded in the off-chance that thevolume may be used later (e.g., where asbestos fibers are identified, the air-borne fiber counts may be determined). The air volume, however, will rarelybe relevant to the forensic microscopist.

Cascade Impactors

An adhesive film may be placed on the surface of each stage of an impactor,and the sample collection time may be limited while separating the collectedmaterial by size. As the particles tend to impact singularly, the microsco-pist may analyze each adhesive film directly. Separation and isolation arealready completed by this sampling method.


• Equipment: air sampling pump• Collection media: cascade impactor with special adhesive film• Flow rate: 28.4 liters/minute• Recommended sample duration: 5 to 10 minutes

Other Methods

Other air sampling techniques that have been used include impingers andcyclones.Processingthesesamplesmaybemore involved(e.g., time-consumingand expensive), yet impinger and cyclone samples allow for dilution and

ForensicsofDust 239

separation of the collected material. They are, however, limited in their abilityto collect only certain particle sizes. The impinger collects particles greaterthan 1 micron in diameter, those that are visible under the light microscope.On the other hand, the cyclone collects nonfibrous particles of less than5 microns. Anything greater than 5 microns or fibrous in nature is likely to beoverlooked.

Bulk Sampling

An alternative to the specialty tape and problems associated with the cleartape is “bulk dust” sampling. When dealing with large deposits of dust (ordirt), bulk sampling becomes the most feasible approach. Define an areawhere the collection is indicated and scoop/scrape the dust from the surface,using a fiber-free (e.g., a cellophane envelope), contaminant-free scraper (e.g.,a stainless-steel spatula). At the laboratory, large samples are homogenized,and a representative sampling of the entire mix will be extracted. So whendeciding how much to collect, the environmental professional may wish torestrict sample sites and limit collection to clearly defined, distinct areas.For instance, a specific air supply louver in a complaint area and settled dustfrom a recently cleaned table surface are clearly defined, delineated samplelocations.

Then, too, a building material or structural component may appear to becontaminated with an unidentified substance that has become part of its sub-strate. For instance, a weakened spot on a steel beam may be associated withan unidentified material, or gypsum board may have what appears to be amicrobial growth. If possible, collect a piece (e.g., at least a 4-inch square sur-face) of the substrate. Place it in a plastic baggie and ship with instructions tothe lab that you wish to know what the associated material is and describe itsphysical appearance as best you can. If the instructions are incomplete, thelaboratory might just miss the point of the request. Be clear and concise inyour instructions!

Textile/Carpet Sampling9

Micro-vacuuming of textiles and carpeting has proven inferior to directextraction and sonication of textiles and carpeting. A comparative study wasperformed of asbestos contamination of carpets that demonstrated the dif-ference between the two methods. See Table 14.2.

Textile/carpet sampling involves cutting a piece from the textile/carpeta minimum of 100 square centimeters in size. This is placed in a wide-mouth polyethylene jar or zip-lock bag. At the laboratory, the sought aftersubstance is extracted, suspended in water, and filtered through a polycar-bonate filter or cellulose ester filter for analysis by transmission electronmicroscopy. This method is primarily used for asbestos analysis in carpetsamples.



Depending on experience and equipment, the microscopist has the abil-ity to detect, identify, and measure trace quantities of a substance downto the elemental composition and structural configuration of molecules.Most particles larger than 1 micron in size can be identified by visiblelight microscope analysis. On the low end of sizing are some bacteria(e.g., 1 micron), many molds (e.g., 1 to 10 microns), and actinomycetes (e.g.,1 to 5 microns). On the high end are some molds (e.g., up to 50 microns insize), fibers (e.g., in excess of 100 microns in length), and hair (e.g., 10 to inexcess of 100 microns in length). Then, too, particles may carry chemicalson their surfaces (e.g., formaldehyde adsorbed onto the surface of dust).These, too, may be identified.

Particles that are 1 micron or less are more difficult, if not impossible, to seeby visible light microscope analyses. Under these conditions, special micro-analytical procedures may solve the dilemma and confirm suspect materi-als. Forensic microscopy is only limited by the skills and experience of themicroscopist. Some of the methods used are mentioned herein.

Visible Light Microscopy

An experienced microscopist may identify most, not all, sample particu-lates (greater than 1 micron in size) in a few seconds, if not immediately,without altering the chemical and physical properties of the material. Likedifferentiating a tree from a light post, when seen and identified on a fre-quent basis, most microscopic material is easily identified.

TABLE 14.2

Comparative Sampling Approaches for Asbestos-ContaminatedCarpet Analyses

Sample Number Carpet Piece Microvac

1 4,800,000 21,0002 3,300,000 30,0003 <5,400 <3504 3,800,000 74,0005 3,000,000 50,0006 2,500,000 95,0007 3,600,000 18,0008 4,700,000 35,000

Source: Millette, J.R., et al. Environmental Choices Technical Supplement (March/April 1993).

Note: < = Indicates the limit of detection for the method used.

ForensicsofDust 241

Visible Light Microscopy: Identification of particlesgreater than 1 micron in size

Parameters that are used in the microscopic analyses include, but are notlimited to, the following:

• Size• Shape• Color• Homogeneity• Transparency• Magnetic qualities• Elasticity• Specific gravity• Refractive indices• Birefringence• Extinction• Dispersion staining

Sample particles (larger than 1 micron in size) are identified with minimaleffort by visible light microscopy. This is done through differences in size,shape, homogeneity, color, transparency, magnetic qualities, and specificgravity. Again, on occasion, additional information is necessary for positiveidentification of suspect material or for identification of a substance that isunfamiliar to the microscopist.

The remaining parameters are ascertained through the use of polarizedlight microscopy, which greatly increases particle characterization and com-petence. It also ensures positive identification of types of fibers, minerals,and some industrial pollutants.

Specialized Microscopic Techniques

Specialized techniques are available for use when the particle size is lessthan 1 micron, when the price is not a consideration, or for confirmation inlitigation or high visibility cases. Occasionally, other techniques become nec-essary when dealing with extremely small particles or exotic mixtures.

X-Ray Diffraction11

Other than visible light microscopy, x-ray diffraction is the only other tech-nique available that permits identification and differentiation of crystals.


Where there are three different forms of silica (i.e., quartz, tridymite, andcristobalite), chemical analysis may confirm the presence of silica but not beable to differentiate the type.

The sensitivity is down to approximately 10–2 nanograms, and the pro-cedure is nondestructive of the sample. Although it may be as small as oneparticle, measuring 5 microns in diameter, the ideal sample size is 40 to50 microns. The smaller particles require more extensive manipulation (e.g.,removal of air from within the camera), so the cost for analysis may increasewith smaller particle sizes.

X-ray diffraction measures the interplanar spacing of atoms in a crystal.Spacing is unique for every compound, and each is identified by comparisonwith known compounds. This comparison is performed with the assistance of acomputer file that has well over 20,000 substances in its data bank. The data fileis constantly being expanded. If a sample is suspect of containing a specific sub-stance that is not on file, the known substance (in its pure form) may be scannedand entered into the data banks to be used as a reference for the unknown.

Scanning Electron Microscope12

Scanning electron microscopy (SEM) comes into play where a sample sizeis too small to be observed by visible light microscopy (equal to or less than1 micron in diameter) or where greater resolution and depth of field of largerparticles (from 1 to 100 microns in diameter) is required. It operates in asimilar fashion to that of the stereo binocular microscope, refracting electronbeams (instead of visible light) off the surface of a sample. These refractedelectrons are projected onto a viewing camera or film to permit the analystto observe the structure(s).

Scanning Electron Microscopy:morphology, spacial, and inorganic elemental

analysis of particles down to 0.2 micron in size

The SEM is capable of magnification of particles typically around 0.2 micronin diameter. Where the depth of field for visible light microscopy is around1 micron, it is 300 microns for the SEM. This allows for greater contrast andease of viewing the unknown sample.

The resolution is about 300,000 times the actual particle size, or 200 timesgreater than that of the most powerful light microscope (which has a magni-fication capability of 1500 times). Smaller particles are more readily observeddue to the increased magnification. This is generally the case with metalfumes, clays, some pigments, bacteria, and viruses.

Another added feature to the SEM is the ability to add an energy dispersivex-ray analyzer (EDXRA) to the unit. This x-ray analyzer is capable of greater

ForensicsofDust 243

detection than that of x-ray diffraction. Where the x-ray diffraction providesa means for identifying compounds, the EDXRA can detect elements (abovenitrogen on the periodic table). Most analysts agree that without this addedability for detecting elements SEM would be inferior to visible light micros-copy in its detection ability.

Still spores, bacteria, and viruses can be identified as spores, bacteria, andviruses only. Viruses and bacteria are generally smaller than 1 micron indiameter and can be identified as such only through the use of SEM due tothe higher resolution. To type these biological components by genus and spe-cies, the sample must still be cultured or manipulated in some other fashionbesides microscopy.

Particles greater than 1 micron in diameter may still require the EDXRAfor identification and are frequently more easily identified by visible lightmicroscopy. Thus SEM with EDXRA may be used as a secondary means ofidentification for the larger particles, and as the primary means of analysisfor particles at or less than 1 micron in diameter.

Transmission Electron Microscope13

Transmission electron microscopy (TEM) analysis works in a similar fashionto that of the biological microscope by penetrating a sample with focusedelectron beams instead of visible light. These electron beams are observed ina similar fashion to that of SEM where the beams are projected onto a view-ing screen or film.

Transmission Electron Microscopy:identification and product analysis of particles/

components down to 0.5 x 103 microns in size

The depth of focus is 1 micron and its resolution is 0.5 × 103 micron. Themaximum prepared particle thickness is 0.05 micron, and the maximumsample diameter is 3 millimeters. The TEM can be fitted for selected areaelectron diffraction (SAED) and EDXRA. The SAED functions in a similarfashion to that of x-ray diffraction, limiting the coverage area, and the elec-tron beam is used to measure the interplanar spacing of atoms in a givenarea. The SAED information is compared with a data bank for compoundidentification, and the EDXRA provides the elemental fingerprint.

Particles are scanned for structural appearance, compound identification,and elemental fingerprinting. If a search is performed for a specific substance,the microscopist reports results in percent by weight. It is important to notethat where asbestos content is performed by polarized light microscopy, theresults are provided as percent by volume where the definition of asbestos isa mixture containing greater than 1 percent by weight of certain types. Theonly means available to provide true percent by weight is through TEM.


Electron Microprobe Analyzer14

The electron microprobe analyzer (EMA) is an ultra micro analytical toolthat can be used to enhance a light microscope, SEM, x-ray fluorescence, andcathode luminescence. It is also referred to as mass scanning.

A sample containing a large number of small particles may be rapidlycharacterized by chemical composition. This is generally performed by auto-mation of the specimen stage, scanning beam, and spectrometer. In this case,a few thousand particles can be characterized from any given sample.

The electron microprobe analyzer may be used to locate a needle in a hay-stack. If searching for a known substance that may be present in a sample inonly parts per million, or trace levels (e.g., asbestos fibers in urban air), theanalyzer is ideal. It is set up to identify an element, or combination of ele-ments, that are present in the substance of concern. Each time the substanceis located, the stage stops, and that particle is quantitatively analyzed. Thenthe stage continues its search. The ideal lower limit for adequate identifica-tion is 0.1 percent, but the method is capable of locating down to 10–4 percent.The latter involves a considerable amount of time consumption, thereforecost, but it is possible.

Elemental analysis is possible of samples as small as 1 micron in diameterand as minimal as 1 percent of a sample. This constitutes a detection limit aslow as 10–4 nanograms. An electron beam is focused to a spot smaller than1 microns square in area. The characteristic x-rays emitted from the spot areanalyzed for wavelength, or energy, dispersing systems both quantitativelyand qualitatively. A limitation is its inability to detect lithium (sometimesberyllium), and 100 parts per million is the lower limit of detection for mostelements.

The analyzer is capable of mass scanning of between 4 and 50 particles perhour. The speed and ease of analysis allows for any given sample, containingup to 1000 unknowns, as little as 20 hours to analyze a 24-hour turnaround,in a pinch!

Ion Microprobe Analyzer15

The ion microprobe analyzer (IMA) provides a means for mass spectrom-etry on small particles or small areas of bulk samples. This method is one ofthe most sensitive tools available for small particle analysis. It is sensitive toevery element in the periodic table and can, under ideal conditions, detectas little as 10–20 grams of some elements, and 10–19 grams of most elements.It is fully capable of analysis of trace amounts of material from samples assmall as 1 micron and, in some instances, can obtain parts per billion ofsome elements. The time required for semiquantitative analysis is typically40 seconds, or as short as 4 seconds.

ForensicsofDust 245

The instrumentation consists of a light microscope (which is used tolocate the sample), an ion source, a column of two electrostatic lenses, anda mass spectrometer.

The versatility of the IMA is similar to that of the electron microprobe ana-lyzer, yet it is much faster and can assess particles that are much smaller (e.g.,1 part per billion instead of 1 part per million). Any airborne, waterborne,or contaminant particles can be analyzed with this tool. A few examplesinclude the analysis of micrometeorites, lead particles from auto exhaust,and contaminants on integrated circuits.

Commercial Laboratories

Due to the extensive training required to be proficient in all aspects of thisfield, there are a limited number of laboratories capable of responding to allthe nuances that may arise in an environmental evaluation. An experiencedmicroscopist may cost a little more per hour yet be able to provide resultswith less time expenditure than one with less experience and lower rates.

On the other hand, the desired information may be obvious (e.g., heavyconcentrations of ragweed pollen) and readily apparent to even the inexperi-enced microscopist who may serve as an initial previewer. Many of the com-mercial laboratories are accustomed to analyzing primarily for asbestos only.Query the commercial laboratory as to its capabilities and limitations. Thoseexperienced in performing forensic analyses can easily apply the forensicknowledge to environmental issues.

Charging only a nominal fee to perform a more complete analysis, somemold/spore laboratories provide results in terms of total fibers. A forensiclaboratory should be able to identify each of the fibers (e.g., rodent hairs,fiberglass, cellulose) and much more.

Summary

In conjunction with an experienced laboratory, forensic dust sampling is avery powerful tool for identifying a broad range of unknowns. Not only canthose substances that are more commonly encountered be identified, butforensic microscopy provides an avenue for identifying unknowns wherethere are no traditional methodologies or no readily available means foranalysis. Not only can particles be identified, but many metals and chemicalscan be identified. This approach to indoor air quality takes the investigatorto a new dimension in sampling methodologies.


References

1. McCrone, W.C. Detection and Measurement with the Microscope. American Laboratory. (Reprint) (December 1972).

2. Hedge, A., W. Erickson, and G. Rubin. Effects of Man Made Mineral Fibers in Settled Dust on Sick Building Syndrome in Air Conditioned Offices. Proceedingsfrom a Conference on Indoor Air (1993).

3. McCrone, W.C. The Solids We Breathe. Industrial Research. (April 1977).4. Bisbing, R. Clues in the Dust. American Laboratory. (Reprint) (November 1989).5. McCrone, W.C. Microscopy and Pollution Analysis. Reprint from Measuring,

Monitoring, and Surveillance of Air Pollution, Air Pollution. Vol. 111 (1976).6. McCrone, W.C. Air Pollution, 3rd ed. Academic Press, Inc., New York, Vol. 111

(1976), pp. 101–2.7. Bisbing, R.E. Microscope and Pollution Analysis. (Oral communication) McCrone

Associates, Inc., Chicago (June 1995).8. Millette, J.R., T. Kremer, and R.Wheeles. Settled Dust Analysis Used in Assessment

of Buildings Containing Asbestos. (Bulletin) McCrone Environmental Services,Inc., Norcross, Georgia (1990), pp. 216–19.

9. Millipore Product Literature. Millipore Corporation, Bedford, Massachusetts(1996).

10. Millette, J.R., et al. Methods for the Analysis of Carpet Samples for Asbestos.Environmental Choices Technical Supplement (March/April 1993).

11. McCrone, W.C. Air Pollution, 3rd ed. Academic Press, Inc., New York Vol. III(1976), pp. 114–15.

12. Ibid., pp. 118–21.13. Ibid., pp. 121–32.14. Ibid. pp.132–38.15. Ibid. pp.138 –43.

247

15AnimalAllergenicDust

The neglected partner in allergenic complicity with pollen and mold sporesis animal allergens, or house dust. Only within the past 10 years have clini-cal studies revealed a strong relationship between levels of animal allergensin dust and allergy symptoms. Technology has evolved. Methods have beenrefined, and immunoassay technology comes into the limelight.

Detection and quantitation of a wide range of antigenic biological andnonbiological substances are now possible through immunoassay analyti-cal methods. Allergenic substances that are processed include proteins, gly-coproteins, hormones, peptides, chemical haptens, and drugs. Of particularinterest to the environmental professional, researchers have developedimmunoassays for animal allergens, predominantly those derived frommites, cats, cockroaches, and rodents. Methods have also been developed forcertain species of fungi (e.g., Aspergillus flavis) and for latex.

An immunoassay involves identification of the antigens by creating anti-bodies for the express purpose of tagging specific materials. Quantitation isbased on the antibody antigen complexes. Thus inununoassay analyses arehighly specific and quantifiable.

The sampling procedure is simple and inexpensive. Yet the sampling strategyand results interpretation require a thorough understanding of the process.

In the past, the medical community has performed the sampling, but mostof the sampling has been diagnostic, involving expensive clinical tests per-formed on the distressed sufferer. Where allergies appear widespread in anoffice building or other problematic indoor air environment, the perplexedfacilities manager or homeowner seeks assistance from the environmental pro-fessional. Diagnostic tests on all the building occupants can be expensive andtime-consuming. In such instances, dust sampling is by far the more feasiblealternative.

Yet without the benefit of clinical studies, extensive allergy complaintsmay pose a medley of possibilities. Some of the allergy sufferers know thespecific antigens that cause their individual reactions. Known allergens mayassist in narrowing the possibilities, where dust sampling may be performedin order to:

• Define allergen levels in residences of asthma patients.• Identify areas or sources of elevated levels of allergen(s).• Determine the effectiveness of allergenic dust control measures.


Most of the information provided within this chapter is intended to aidin the search for the more common allergens and expound on those thatmay be overlooked in isolated instances. The animal allergens are morewidely understood and are an evolving issue of concern in the environ-mental field.

Animal Allergens

Animal proteins are high molecular weight, complex molecules that can elicitan allergic reaction. Wherein the environmental professional is concernedwith airborne exposures, the allergens must be present in large quantities andsmall enough to become airborne. Typically, those animal allergens that aremore commonly encountered are parts and pieces of an insect or mammal.Those that receive the greatest attention and are frequently studied are dustmites, dog/cat dander, and cockroach body parts. The probability of elevatednumbers of these allergens is considerable in most indoor air environments.

Mites/Spiders1, 2

Mites are small to microscopic sized, generally parasitic arachnids with fourpairs of legs in their adult stage and little or no differentiation of the bodyparts. Many cause allergic rhinitis, human dermatitis, and general allergicreactions. They differ in habitat and associations and are broadly catego-rized by their associations. See Table 15.1 for a breakdown of the most com-monly cited allergenic mite types.

Storage mites are usually of the genera Lepidoglyphus and Tyrophagus. Theyrely on decaying vegetation as a food source and are normally associatedwith agricultural environments. They have been identified as causing aller-gic rhinitis in dairy farmers. Thus allergy-causing storage mite exposuresare limited more to the outdoor environments where there is decaying veg-etation than to the indoor air environment. Decaying vegetation is a require-ment for their presence.

Itch mites and mange mites may cause dermatitis and have occasionallybeen implicated with house dust mites. Their main food sources are cheese,dried meats, flour, and seeds. They damage and contaminate these commod-ities while having a means of transportation through human handling of thefood products. The result is grocer’s itch, or miller’s itch.

Some mites and spiders attack man and other animals directly, burrowinginto their skin. These are the ones that hikers and hunters often encounterin wooded areas.

Others cause mange, which results in itching and hair loss. Mange mitestypically attack domestic animals and are generally visible to the naked eye.

AnimalAllergenicDust 249

Yet following a heavy infestation, dead or alive, their bodies may still serveas antigens.

House dust mites have undergone considerable study as they are not onlyallergenic, but they typically are found indoors. See Figure 15.1. They bask inwarm, moist, dark environments. Ideal temperatures are between 70°F and80°F. They thrive where the relative humidity is in excess of 65 percent, andthey hide from sunlight.

Sites where they tend to commune are places that have sloughed epithelialcells (which tend to retain moisture), such as beds, upholstered furnishings,and carpets. The average human will lose as much as five grams of epithelialskin cells per week. Wherever these epithelial cells can be found, the miteshave a source of food.

In the United States, dust mite infestations and allergies tend to be seasonalwith a preference for the warmer, humid months (e.g., summer). Whereastropical climates may provide a perpetual, unrestricted habitat for blissfulinvaders all year round, the pesky little critters predominate mostly betweenJune and August.4

The house dust mites are between 250 and 500 microns in size, barely vis-ible by the naked eye and frequently overlooked. The allergenic portion of

TABLE 15.1

Allergenic Mites

Class: ArachnidaOrder: Acari (Acarina)Suborder: Psoroptoidea

Storage MitesFamily: Acaridae, Glycophagidae, and BlomiaGenus/species: Acarus siro

Glycophagus domesticusLepidophagus destructorTyrophagus putrescentiaeBlomia tropicalis

Itch MiteFamily: SarcoptidaeGenus/species: Sarcoptes scabiei

Dust MitesFamily: PyroglyphidaeGenus/species: Dermatophagoides pteronyssinus

Dermatophagoides farinaeDermatophagoides microcerasEuroglyphus maynei

Source: Halsey, J.F., and M. Colwell. Allergy Basics for IAQ Investigations. (Handout)Professional Development Course, American Industrial HygieneConference and Exposition (May 20, 1995). With permission.


these mites is thought to be the body parts and pieces and their fecal mate-rial, which is 10 to 35 microns in diameter. The body pieces are considerablysmaller than 250 microns and not identifiable by microscopic analysis. As amatter of course, the size has a bearing on the airborne allergens. If greaterthan 40 microns, airborne substances will settle out within 20 to 30 minutes.Thus inhalation of the material is most likely to those components of the dustthat are smallest and in areas often disturbed.

Areaslikelytobedisturbedaresituationdependent.Commonlyinvolvedactiv-ities that might stir up dust include, but are not be limited to, the following:

• During and shortly after vacuuming• Considerable activity on and disturbance of upholstered furniture• Considerable activity on and disturbance of carpeting• When making a bed and fluffing pillows• Sleeping on contaminated bedding or upholstered furniture

As for the actual allergens, several mite-associated proteins are impli-cated, and studies have been predominately on three species in the gen-era Dermatophagoides, which is common in North America and Europe.To a lesser extent, the genera Euroglyphus and Blomia have been studiedas well, but they are more commonly encountered in Central and SouthAmerica.

FIGURE 15.1The dust mite is a commonly used representation of allergens. (Courtesy of A.L.K. Abello andA/S Honsholm, Denmark.)


For the purpose of allergen testing using immunoassay techniques, the dustmite allergens are genus and species specific, and each of the species has asmany as 40 different proteins that could cause an allergic reaction. Whereidentified, allergenic proteins are referred to by group. See Table 15.2 for themost commonly implicated allergen types and associated allergenic proteins.

Where a group of allergenic proteins has not been identified, a homoge-neous mix is referred to as polyclonal. A polyclonal assay involves multipleantigens from the same life form.

Booklice

Oftentimes, the layman will refer to paper mites as being the source of aproblem, possibly because the individual associates their allergies with themounds of paper they work with and hearsay. The reference to paper mitesis a red herring, a fictitious contrivance of the news media. Entomologistsfrown on desperate attempts to track these elusive pests under the headingof mites. While some entomologists will confess ignorance, others will spec-ulate that the reference is more likely to that of storage mites that, at times,are associated with cellulose, or paper products. Another consideration isthat of booklice are neither mites nor lice, but insects. See Figure 15.2.

Booklice belong to the order Psocoptera. These are small, soft-bodiedinsects with three pairs of legs and measuring less than 1/4-inch in length.They may or may not have wings. They have been reported as causing aller-gic symptoms in places with large amounts of paper. They feed on molds,fungi, cereals, pollen, and dead insects. Their preferred habitat is moist areasand humid environments, and they rarely cause damage to the spaces theyoccupy. They are, however, a nuisance to allergy sufferers.

Cockroaches and Other Insects5

Insects are typically visible, have three pairs of legs in their adult stage, andpossess three distinct body regions. They are, therefore, easy to identify, anda large indoor insect population rarely remains unnoticed. The most com-mon is the ever-present cockroach.

TABLE 15.2

Allergenic Dust Mites and Immunoassay Test Groupings

Allergenic Proteins

Type Group I Group II Group III

Dermatophagoides farinae Der f 1 Der f 2 Der f 3Dermatophagoides microceras Der m 1 – –Dermatophagoides pteronyssinus Der p 1 Der p 2 Der p 3Euroglyphus maynei Eur m 1 – –


Of the 55 species of cockroaches that inhabit the continental United States,less than 10 are indoor residents. Of these, the most common, particularlyin southeastern United States areas, are the larger American cockroach(Periplaneta americana) and the smaller German cockroach (Blatella germanica).See Figure 15.3. As the larger ones consume the smaller, more prolific ones,they do not tend to cohabit within the same residence. It should be visuallyapparent as to which species one is dealing with. Yet allergy tests are genusand species specific. See Table 15.3 for the allergenic groups.

Recent studies, however, suggest that the cockroaches secrete their allergensonto their bodies and other surfaces in their environment. Thus examinationof allergenic material may or may not disclose the presence of associateddebris and fecal material. The only means of confirming the presence of cock-roach allergens is through immunoassay analysis of suspect dust.

There has been considerable, unconfirmed speculation as to the source ofthe cockroach allergens. Some considerations are as follows:

• Saliva• Body parts and pieces• Egg shells• Fecal particles

FIGURE 15.2Photomicrograph of an “unconfirmed” booklice, a component of office dust, lifted by tape. Itsapproximate size is 500 microns, and this image was observed, in its entirety, under 100x magni-fication. Immunoassay testing was for cockroach allergens only, which were found to be exces-sive. Dust mite allergens were low, but the method was specific for dust mites, not booklice.


Cockroaches are able to adapt to low ambient humidity, yet actively seek asource of water. For this reason, indoor cockroaches are most likely foundaround water pipes, pet water bowls, evaporative areas around refrigerators,leaking faucets, and wet carpeting. Although in most cases their presence isreadily apparent, cockroach allergens have been measurable in up to 15 per-cent of homes that had no visible clues that they might be present. Keep inmind that they do not have to be alive for the allergens to promote a reaction,and the source of cockroach allergens is still unclear.

Although there have been numerous allergen studies performed of theever-enduring, ever-present cockroach, many other insects have been impli-cated as well. Though most other insects are generally found in outdoorenvironments, body parts and pieces may be conveyed indoors. They mayattach to clothing. They may enter open windows and doors in search offood or light (e.g., june bugs). There may be air movement from the outsideto enclosed air spaces indoors. Indoor accumulations of insect carcasses arecommon. The indoor environment may become a repository of debris.

FIGURE 15.3The American cockroach (Periplaneta americana) [left] and the German cockroach (Blatella germanica) [right].

TABLE 15.3

Allergenic Cockroach Material and Immunoassay Test Groupings

Allergenic Group I

Proteins Group II

Blatella germanica Bla g 1 Bla g 2Periplaneta americana Per a 1 –


Outdoor workers are exposed, at times, to insect fragments and debris atlevels in excess of ragweed pollen. Insects that are suspect of causing aller-gies include the following.3

• Crickets• Bean weevils• Houseflies and fruit flies• Some species of moths• Waterfleas• Butterflies• Bed bugs• Silkworms• Mayflies• Caddis flies• Aphids• Chiromomid midgets• Honey bees• June bugs

Some occupations, due to their associations, harbor potential exposures forinsect infestations. Some examples may be found in Table 15.4.

Domestic Animals6

Most allergic substances that are associated with domestic animals are pre-dominately exposure problems in environments where the animals reside.The obvious is overstated. Homes, kennels, pet shops, and laboratoriesare locations where the allergens are most likely to be found. However,office environments should not be excluded from consideration. Although

TABLE 15.4

Occupational Exposures to Insects

Entomologists: locusts, crickets, fliesGrain mill workers: beetles, grain weevilsLoggers/lumber mill workers: Tussock mothFishermen/bait handlers: meal worms, maggotsPoultry workers: Northern fowl mitesBakers: storage mites, grain weevilsSmall animal handlers: fleasHoney-packing plant workers: honey bee dustPet food processors: Chironomids


rare, elevated exposures have been reported where the source has not beenreadily apparent. The most commonly targeted domestic animals are catsand dogs.

Cats

Although cats are maintained in 28 percent of all American households, only2 percent of the U.S. population has allergies to them. Interestingly, thosewho are allergic to cat allergens may never have lived with cats.

The source of allergenic material may be any of a number of feline-associ-ated materials, and tests are performed for the allergen Fel d 1. There has beenconsiderable speculation as to the actual chemistry of the allergen, but mostresearchers have speculated that the allergen is somehow transferred, pickedup, or concentrated by saliva. When the cat grooms itself by licking, the aller-gen is spread or transferred to the hair and epithelial cells. The following isan abbreviated list of known and suspect sources/transfer vehicles:

• Saliva• Sebaceous glands• Hair• Epithelial cells• Epidermis

The sex and type of cat are factors that contribute to environmental levels ofcat allergen. Male cats shed more allergens than female cats. Patients’ symp-toms vary in severity, depending upon the type of cat to which they areexposed to (e.g., a domestic cat versus a Persian short tail).

The cat allergens are carried on particles less than 2.5 microns in diameter(i.e., PM 2.5). At this size, after becoming airborne, they will remain sus-pended in an undisturbed environment for hours. The ease with which theseallergens become airborne is the reason for apparent excesses in sensitivity.

Even though there are excessive cat allergens in a household where oneresides, all indoor environments have detectable levels. In houses with cats,there is typically in excess of 10 micrograms per gram (µg/g) of Fel d 1 in thedust, and levels have been reported as high as 7000 µg/g.7 The allergen mayalso be transferred by clothing and other articles from a high exposure envi-ronment to otherwise cat-free environments. Houses that have never hadcats may have levels of less than 1 µg/g in the dust, but levels in excess of thisshould not be surprising.

Dogs

Dogs are maintained in an estimated 43 percent of American homes, andone regional study indicated that as many as 17 percent of the population


was allergic to dog allergens. There have been 28 different allergens foundto be associated with allergic symptoms. The specific antigen to which mostpatients react is designated as Can f 1. Can f 1 consists of an extract of the fol-lowing dog associated materials:

• Hair• Dander• Saliva

Most environments where dogs are found have in excess of 120 µg/g of Can f1 in the dust. Homes without dogs typically have less than 10 µg/g. The sizeof the allergen-carrying material or contaminated particles is unknown.

Rodents8, 9

Exposures to mouse and rat allergens are typically associated with animalresearch laboratory vivarian and indoor spaces (e.g., homes and office build-ings) infested by rodents. Of the approximately 35,000 workers in the UnitedStates exposed to rodent allergens in animal research laboratories or breedingfacilities, more than 20 percent of the workers experience allergic symptoms.

Rodent infestations may deposit allergens unbeknownst to building occu-pants. Awareness of the potential opens another door for search and disclo-sure of possibilities. Complaints of a urinelike odor should alert suspicion.

Two other allergens have been associated with mice. One of the mouseallergens, referred to as Ag 1, is related to the mouse urine and is designatedMus m 1. Mus m 1 is produced by the liver and salivary glands, excreted inthe form of urine and saliva. As it is associated with testosterone, Mus m1 is excreted predominately by male mice. Other factors affecting quantityare strain and age. The other mouse allergen, referred to as Ag 3, has beendetected in hair follicles (e.g., fur and dander extracts).

Two allergens have also been associated with rats. However, they are bothassociated with the rat urine. These allergens, referred to as Ag 4 and Ag 13,are designated Rat n 1.

Although typically associated with particles of 10 microns in size or less,airborne exposures to rodent urine rarely occur unless contaminated bed-ding is disturbed, and elevated humidity has been reported to diminish air-borne exposures. Most exposures occur where rodents are maintained inlarge numbers (e.g., laboratory environments). The amount of material thatmay become airborne is generally related to the type of litter and bedding.The allergen is generally released into the air during cage-cleaning activi-ties. In one laboratory animal cage-cleaning study, the airborne levels werereported between 19 and 310 nanograms per cubic meter of sample (ng/m3).During quiet times, when there were no disturbances, the levels dropped toaround 1.5 to 9.7 ng/m3. Rodent allergens may also be deposited on ceiling


tiles and in carpeting. Disturbances of contaminated areas may result inairborne releases of material as yet not identified to be present in a givenenvironment (e.g., rodent infestations). There is no published informationregarding reported airborne or dust levels of rodent allergens.

Farm Animals10

Along with the arthropods, pollen, mold spores, and bacteria, farmers andfarmworkers are potentially exposed to farm animal allergens. The moreprominent allergenic exposures are attributed to cows, horses, and pigs.

Cow dander and urine, designated Bos d 2, have been reported to causeallergic rhinitis in dairy farmers. Airborne levels have been reported as highas 19.8 µg/m3.

Horse allergens (Equ c 1, Equ c 2, and Equ c 3) are very potent. Exposuresmay occur occupationally or to pleasure horseback riders. The horse aller-gens are related to hair, dander, and epithelial cells.

Pig allergens are rarely reported to be a problem and are considered weakantigens. The allergenic material has, however, been identified. Swine work-ers have been found to have antibodies against swine dander, epithelium,and urine. Airborne levels have been reported up to 300 µg/m3. Yet thereappear to be minimal complaints and concerns for swine allergies.

Other Animals10

Rabbit dander and guinea pig urinary proteins/saliva have been reported tocause allergies. Both are found in homes, pet stores, and laboratory facilities.

Even rarer are exposures to bat guano and reindeer epithelial cells. Batdroppings accumulate inside roof attics and cave dwellings. Asthma likesymptoms are generally reported in association with workers exposed tobats in indoor working environments.

Reindeer epithelial cells, which are associated with leather processing, arealso known to cause allergic reactions. Airborne exposure levels have beenreported in processing areas at a concentration of 0.1 to 3.9 µg/m3.

Occurrence of Animal Allergens

Farm, laboratory, and pet environments are easy marks. The source of aller-gies is direct and readily apparent to the allergy sufferer when symptomsworsen in their presence. The greater the number of animals, the greater isthe potential for elevated exposures. Whereas an individual may not at onetime have been sensitive to a given allergen, an extreme dose may later pre-dispose them to developing symptoms at lower exposure levels in the future.


Most of these allergy sufferers know what it is they are allergic to. A smallpercentage of the population, however, seems to be sensitive not only to thetypical allergens, but to just about everything.

In office environments with no apparent sources of animal allergens,the latter more allergen-sensitive individuals will be the first to start com-plaining. It has been estimated that these ultra-sensitive individuals con-stitute only about 4 percent of the population. Yet as levels of an allergenincrease, the numbers impacted increase as well. With more complaintscomes greater concern for locating a source. As animal allergens are possi-ble contributors to a given environmental invasion, a means for identifyingand quantifying their presence is made available through a well-thought-out strategy, collecting dust samples, and analyzing the collected materialby immunochemisty.

Sampling Strategy

A well-thought-out strategy is vital for identifying a problem and obtainingmeaningful results. If the environment is an office building and large num-bers of people are impacted, the problem areas must be clearly identified.

Questionnaires should be filled out by all those in the area of concernas well as an area where there are no complaints of allergylike symptoms.Identify known problem areas and nonproblem areas. Develop associations.Attempt to limit the possibilities. A screening tool for rodents, using ultra-violet light, may also be added to the list of considerations. The method isdiscussed in the next section of this chapter.

Other than bacterial and mold spores, the most typical allergenic materi-als found in office buildings are dust mites and cockroach allergens. Cat anddog allergens are more common in homes but may be transferred to officeenvironments. All other allergens previously mentioned are rare occurrencesin office/industrial environments or are occupationally related.

Some building occupants may have had allergy testing (e.g., skin or allergyblood tests) performed and know what allergens to which they are allergic.A few of the more common blood tests available through physicians includethe following:11

• Plant pollen• Fungi/molds• Thermophilic actinomycetes• Storage mites• Animal dander• Isocyanates


• Formaldehyde• Gums/adhesives• Anhydrides

The greatest dilemma to the environmental professional is that of locatingareas most likely to be source origins and including only these in the sample,not the disassociated areas as well. For instance, if complaints generally arisein a given area where there is a lot of disturbance of the carpeting and dustmites are suspect, the area where the traffic passes should be sampled toinclude as much of the known problem material as possible, including areasunder desks and along walls that may or may not be the source origins. Eachfalls within a different source type (e.g., carpeting) and functional grouping.

Sample sites should be selected based on suspect source types. These mayinclude, but not be limited to, the following locations:

• Carpeting• Upholstered furniture• On top of ceiling tiles• Ducting in an air handling unit

Functional grouping of sample sites is the most difficult to identify. Theimpacting function may or may not be obvious. In most cases, it will not beobvious, and several functional areas will require sampling. Grouping mayinclude, but is not limited to, the following:

• Dusting shelves• Vacuuming the carpeting• Excessive traffic• Maintenance involving removal of ceiling tiles• Air handler activity

The number of samples taken will depend upon the environmental profes-sional’s assessment of the situation. This will vary in a case by case situation,depending upon the number of possibilities ascertained to be a potentialproblem source. Then, too, sampling of a nonproblem area may be desirablefor comparative purposes.

During data/information gathering, clarify whether a suspect carpet wasrecently shampooed or vacuumed. Maybe there has been a recent infestationof cockroaches or rodents. Even where the vermin have since been extermi-nated, their body parts and pieces may be the exposure allergens. In locatingpossible sample sites where these parts and pieces may have been deposited,the environmental professional should also consider the function of that


location as well. For instance, rodents may eat through air supply ductingand leave a trail of urine and feces. Allergenic material deposited in an airplenum will pose a greater potential for occupant exposures than the samematerial deposited in the corner of a room where there is no foot traffic orair movement.

Record the sample area size and exact location. Although the area size maynot be relevant (samples are analyzed by weight comparisons), this addi-tional information may be useful at some future date, and some profession-als do standardize the sample size (e.g., 1 cubic meter of area). You, onceagain, are not obligated to do the same.

Although there is no set protocol, sample sites should be clearly identified.If floor plans are available, indicate the limits of each site and assign a samplenumber to the area. Otherwise, describe in detail the specific location(s) (e.g.,on top of the ceiling tile above the copy machine) with its perceived function(e.g., frequent above ceiling work necessitates disturbance of ceiling tile atthis location).

Screening for Rodents12

Public health food inspectors screen for the presence of rodents in a foodprocessing plant by using ultraviolet light. Under ultraviolet light, urine willfluoresce (e.g., glow in the dark) either a blue-white or a yellow-white color.Fresh stains fluoresce blue and older stains fluoresce yellow.

Rodents are incontinent. They tend to urinate, mark their trail as they go,and the trail is easy to follow. Rodent hairs also fluoresce as does the urine.For this reason, rodents can easily be identified in areas they frequent (e.g.,food storage areas).

This characteristic of urine fluorescence under a UV light is a simple meansfor inspections—in dimly lighted areas. The darker the area under investiga-tion, the more visible the fluorescent stains.


Due to the complexity and lack of clinical comparison studies, sampling istypically performed on settled dust. Even though air sampling can as easilybe performed, airborne levels vary considerably, because they are based ondust generating activities that are in progress during the sampling period.Depending upon the airborne dust levels, the required sample air volumemay be in excess of 5000 liters. Large air volumes, in turn, embrace extended


sampling times or environmental air sampling devices that are capable ofdrawing 100 to 1000 liters per minute. If sampling times are extended, theactivity that generates airborne dust may not be singularly represented in thesample. Then, environmental sampling equipment is expensive and cumber-some. There are no published procedures for allergenic dust air sampling,and researchers shy away from this approach. On the other hand, settled dustsampling is simple and clinical comparison studies have been performed.

Settled dust sampling is as easy as sucking suspect dust into a vacuumcleaner bag or as involved as using specialty sampling devices designed toperform allergen dust sampling. The following sample collection devices havebeen successfully used by environmental professionals and allergists:13

Standard vacuum cleaner with a filter bag—The filter bag is later detachedand sent to the laboratory for analysis. Although allergenic materialwas found to be retained in the hose preceding the filter bag, stud-ies have concluded that dust collection preceding the hose or at theend of the hose is not significantly different, but capture efficiency issignificant. High retention, high efficiency bags capture and retainfine particulates that are the most concern as fine particles pass thethoracic cavity and enter the lung. Losses may be as much as 30 per-cent to 50 percent with the low retention bags. In a pinch, high effi-ciency bags may be purchased in grocery/discount stores, or withsome foresight, the investigator can get specialty supplies from theirlaboratory (e.g., end of hose filter cassette).

Commercial high efficiency particulate (HEPA) vacuum cleaner with ahigh efficiency filter bag—The filter bag is later detached and sentto the laboratory for analysis. This apparatus is more efficient forretaining particles smaller than 2.5 microns in diameter than mostconventional vacuum cleaners. To avoid cross contamination, assurethe hose and all connectors between the intake wand and filter havebeen cleaned prior to each collection. This approach may be appliedwherein a very large volume sample is required.

Specially designed dust vacuum with an external filter attachment—One spe-cialty design is a small, easy-to-carry vacuum cleaner to which onemay attach collection media (e.g., Dustchek filters) to the end of thehose. The standard and commercial vacuum cleaners generally havea higher sample collection rate, and most of the smaller specialtyvacuums are not practical for collecting samples over large floorareas. See Figure 15.4.

Air sampling pump with a polycarbonate or PVC membrane filter cassette—Samples are drawn through the polycarbonate or PVC filter cassettewith an air sampling pump at a flow rate of 10 to 20 liters per min-ute. This method requires longer sample times to collect the minimalsample size (e.g., half a teaspoon of dust).


A private laboratory performed comparison tests for some of the above sam-pling devices and concluded that there is a significant difference in theirallergen dust recovery. They ranged from half the original sample dose todouble. For this reason, the same method should be used consistently, andcomparison sampling of problem and nonproblem areas is strongly indi-cated so as not to rely on threshold values only.13

Commercial laboratories emphasize that the principal considerationin sampling should be the quantity of material captured. Although someresearchers propose sampling within a well-defined, delineated area or alimited sample duration, the quantity of material collected may not providea good representation of the environment or allow for a sufficient amount ofcollected dust to retain the desired sensitivity (e.g., picograms). Those whodefine the area of surface coverage generally opt for 1 square meter. Otherssample for a specified time period (e.g., 2 minutes), no matter what the sub-strate. They typically vacuum for a set period of time (e.g., 5 or 10 minutes)without regard to the area covered. Yet in both instances, the amount of dustcollected still relies on the amount of available dust. There is no such thingas too much collected dust. There may, however, not be enough.

Ideally, the environmental professional should be able to estimate theamount of dust collected and target a collection in terms of milligrams (withthe volume dependent upon the density of the collected material). Some labo-ratories specify 250 milligrams (i.e., half teaspoon of dust). Others specify 500milligrams. The latter allows for a certain fudge factor with plenty to spare.

Although not required, composite sampling is recommended where sev-eral samples are to be taken and the primary allergenic reservoir has not beenidentified. One study indicated that three composite samples taken from thesame dwelling, each a week apart, gave similar results. There was, however,a noted difference between areas within the same dwelling and between

FIGURE 15.4Specially designed dust vacuum—EMDust Vacuum System (EMLab/P&K, Phoenix, Arizona).


dwellings. Thus composite samples provide a relatively consistent estimate,and discrete samples were useful in finding specific reservoirs.13, 14 Thesesamples may be taken during the collection process or involve a contributionof dust from each of the samples taken in areas known to be associated withairborne allergens. This approach can be useful for screening and minimiz-ing the number of samples requiring analyses for all allergenic dust.

In brief, the most relevant consideration is locating the sample site. Isolateand identify a specific, suspect sample site (e.g., around an area known to beassociated with allergic reactions) along with its function/activity (e.g., highfoot-traffic area or bedding). Then collect a sample (or a composite of severalsamples). Compare suspect problem sites with known nonproblem sites. Ifan allergen appears suspect, discrete area sampling and analyses will aid inthe identification of reservoir(s). Comparison sampling, coupled with pub-lished thresholds, will result in manageable interpretations.


For the purpose of extending the reader’s knowledge into the realm of under-standinghumantest resultsandtheirapplicability toasite investigation,humantesting methods are discussed in brief within this section along with sampleanalytical methods. They are both relevant in assessing suspect allergens.

Human Testing

Airborne exposures to animal antigens may result in allergic rhinitis, sinus-itis, and asthma. Although dermatitis and urticaria have not been implicatedwith airborne exposures, where an allergic individual rubs up against dustladen with a given antigen, the skin may be impacted as well.

Allergenic individuals may be tested by any of a number of means, eachassociated with a different route of entry or means of exposure. The simplestand most frequently used method is the direct skin test.

The skin test technique primarily allows for identification of direct contactallergens only. It will not provide for identification of airborne allergens. Asuspect antigen or group of antigens is placed on the skin surface of theindividual, usually a site on the arm, and a retentive barrier is placed overthe material. The site is checked for redness and urticaria after 24 hours. Apositive reaction indicates the individual is sensitive to all or one of the chal-lenge allergens.

A less commonly used technique is that of blood sample analysis. Bloodis extracted from the individual and analyzed by immunochemical tech-niques. This method is by far the less invasive, not challenging the individ-ual allergy sufferer. The immunochemical techniques used are the same as


those used for the dust samples and are discussed in a little more detailunder “Allergenic Dust Testing.”

The most ideal (and impractical) technique is that of a direct bronchialchallenge to the individual. This method provides a direct insult to theindividual while they are restricted to a challenge chamber where the air-borne allergen types and amounts may be controlled. Whereas one may notrespond to the skin test, the bronchial insult chamber may elicit a respiratoryreaction. The technique is mostly of the research mode and, if accessible, isvery expensive and time-consuming.

Allergenic Dust Testing

Commercial laboratories currently offer routine testing for dust mite, cock-roach, cat, and dog allergens. Although an occasional commercial lab may bewilling to extend their limits, several research institutions have the materialsnecessary to test for the less common allergens (e.g., Mus m 1). Immunoassaytesting of allergenic dust is extremely sensitive and highly specific. Thisspecificity is advantageous in most cases but can be a drawback where asimilar, but not identical, allergen is suspect.

Sample preparation involves sieving the dust samples to separate all mate-rial less than 300 microns in size from the larger material. After it has beenweighed, the smaller material is then extracted with a special buffering solu-tion. An aliquot is taken of this extract and analyzed by any of a numberof immunoassay approaches, involving single antigen specific or multipleantigen quantitation.

A single specific protein, or antigen, is referred to as “monoclonal.” Anexample of a monoclonal test antigen is Fel d 1. Being related to and beingthe strongest (or most studied) allergenic component of a given species, themonoclonal antigens become the most commonly sought after test mate-rial. Yet, due to the extensive amount of attention given to a limited num-ber of allergenic species, the specificity of these methods may restrict thepossibilities.

Those species that have received the most attention are also those thatare known to cause allergies and are prevalent in significant numbers.Figure 15.5 shows the results of a study involving school children and prev-alence of allergies. As a child ages, allergies diminish until ages 25 to 34.15

Thus the prevalence of the various allergies is likely to be less in the adultpopulation.

Multiple proteins from one species or several are referred to as “poly-clonal.” An example of a polyclonal test antigen is cat allergens. They havenot been as extensively studied as the monoclonal antigens, and results seemto be less consistent and are more difficult to evaluate.

The identification of polyclonal antigens, however, may provide directionand assist the environmental professional in isolating the probable allergenicspecies in a dust sample. It serves well as a screening mechanism. More


reliable, easier to use results may then be obtained through the monoclonalantigen tests. If, however, the screening fails to disclose any of the commonallergens, all is not entirely lost.

An environment may be complicated by rare occasional, outbreaks or iso-lated occurrences. Elevated levels of fleas identified in the carpeting of ahigh-traffic medical reception room cannot readily be assayed. Dust thatis known to be the source of allergies cannot readily be identified if thecomponents are other than the more common species. Any of a number ofscenarios may develop. In these instances, some laboratories will preparetest material from a given dust sample and test the blood of the allergysufferers to confirm the allergenic potential of the material. The extracteddust is injected in a strain of mouse. If allergens are present, antibodies areformed. The newly created antibodies are then used to test for dust aller-gen in an allergy sufferer’s blood. Sampling and interpretation require theassistance of a medical doctor.


A dose–response relationship is recognized with allergens as it is withtoxic chemicals. A small percentage of the population will experiencethe effects at extremely low levels of exposure, levels not even noticeable

0%

5%

10%

15%

20%

25%

30%

CockroachParts and

Pieces

MoldSpores

AnimalDander

Grassesand Weeds

Dust Mites

FIGURE 15.5Estimated prevalence of allergies in school-age children and skin reactivity tests. Excerptedfrom Indoor Allergens.16


to a majority of the population. These highly sensitive individuals arethought to comprise less than 5 percent of the workforce. Although this isin line with chemical sensitivity numbers, the more sensitive individualscomprise a group of people who were: (1) predisposed at birth; and (2)exposed to low levels of specific antigens for a long duration. The remain-ing 95 percent of the population will be impacted as the exposure levelsincrease.

Ideally, problem area composite samples should be compared with non-problem area composite samples. Composite results may identify suspectallergens, and discrete samples will help to isolate the reservoir. Althoughmost environmental professionals find great comfort in acceptable lim-its, comparisons with published thresholds should be accomplished withreserve.

Thresholds are in a constant state of flux, and recommended limits mayvary from one laboratory to the next. Observations vary by region, andavailable species differ. Analytical results on the same sample may varyfrom one laboratory to the next. Laboratory findings and allergenic asso-ciation tend to be variable, and these findings change within the same labo-ratory. For this reason, published thresholds should be used as a guideonly!

For reference and review, some of the commonly accepted allergy-causingthresholds can be found in Table 15.5. Yet they are not firm, hard-clad refer-ences. These limits are the result of observations made as to measured levelsand resultant responses of typically nonatopic individuals. These referencevalues will not be applicable for those predisposed to allergies. In these

TABLE 15.5

Allergen Levels in Dust Capable of Eliciting an Allergic Response inthe General Population Not Predisposed Genetically to Allergies

AllergensReference

Thresholds (µg/g)

Dust mite allergens (polyclonal)a 1517

Der f 1 217

Der p 1 217

Group I 1018; 219

Cockroach allergensb

Bla g 1 220

Cat allergensb

Fel d 1 818; 819

Dog allergensb

Can f 1 –

a Dermatophagoides farinae and Dermatophagoides pteronyssinus.b Polyclonal antigens for which there are no published references.


atopic individuals (15 percent to 20 percent of the adult population), theirthresholds may be 1 percent of that which will potentially impact the generalpopulation. It should also be noted that immunoassay reference thresholdsfor plant pollen, mold spores, and chemicals are not listed. This is due to thedirect means available for determining airborne exposure levels for some orto the lack of data for reference thresholds.

Another publication sets different range limits, stating that their measure-ments are the most practical reference values available. They provide thefollowing limits for Group I dust mite allergens:20

• Safe levels: less than 2 µg/g• Levels that may sensitize atopic (genetically predisposed) individu-

als: 2 to 10 µg/g• Levels that may exacerbate previously sensitized individuals: greater

than 10 µg/g

It is thought that the Group I dust mite allergens are associated withfecal material that is relatively small in size as compared with the largerGroup II allergens that are associated with the body parts. Thus theGroup I dust mite allergens are those most likely to be disturbed andbecome airborne. They are the most likely to be associated with allergysymptoms. The Group II body parts may complicate an evaluation wherean individual is close to the settled allergenic material (e.g., sleeping on acontaminated pillow or lying on the floor). All conditions must be takeninto consideration.21

Attempts have been made to report observed thresholds for airborne expo-sures to rodent allergens. One such attempt is summarized in Table 15.6. Asthese numbers are variable and not well-studied, they should be used withreservations. At best, they may be considered reference guidelines. Dust airsampling should be performed through contributing input from the labora-tory that will perform the analysis.

TABLE 15.6

Allergen Levels in Air Reported to Cause an AllergicResponse

ThresholdsObserved

Thresholds

Rodent AllergensAg 3 825 µg/m3

Mus m 1 59 µg/m3

Rat n 1 –

Source: Twiggs, et al. Journal of Allergy and Clinical Immunology.69:522 (1982). With permission.


Other Types of Allergenic Substances

Other types of allergenic substances include indoor/outdoor allergens andindustry-related allergens. Indoor/outdoor allergens are mold spore allergens.

Mold spore dust sampling is rare. Easier, more commonly acceptedapproaches are available for analysis (as has been discussed in previouschapters), and there are limited guidelines for interpretation of results. In onereport, the researchers suggest that should the fungal spores and bacteria indust exceed 10,000 colony forming units per gram of dust (CFU/g) remedia-tion may be indicated. Fungal concentrations on water-damaged materials(e.g., carpeting, gypsum board, or ceiling tiles) are excessive if they exceed1000 CFU/g or 1000 CFU/cm2. However, the analysis for fungal spores relieson spore viability and is performed by the use of a culture media and petridishes. There are no immunoassay methods currently being used for moldspore quantitation in dust, but there are immunoassay methods to deter-mine if an individual is allergic to specific mold spores. History must dictateallergies, and the testing is performed for specific genera.

In certain industries, some of the more common allergenic proteins for whichimmunoassay methods may be performed have been identified in Table 15.7.Currently, however, processing of the samples may involve considerableexpense or the aid of a research laboratory. There has been minimal or no dustsample analyses of these materials, and interpretation may be elusive.

Although each of the above allergens can be analyzed by immunoassaymethodologies, many of the chemicals may be sampled using traditionalindustrial hygiene air and surface sampling methodologies. Once a labora-tory has been identified to perform an analysis, the feasibility of performingair sampling for occupational allergens in the food processing industry willbe based on one’s willingness to collect comparative samples in nonproblemareas and compare them to problem areas or with symptoms in order toestablish an acceptable limit.

Then, also, the environmental professional may encounter a situationwhereby dust from a grain elevator or adjacent food processing plantappears to be causing problems for the occupants of a building that isassociated only by proximity to the food processing plant. In such cases,

TABLE 15.7

Allergenic Materials That May Become Airborne

Industry Type

Food processing grain, flour, coffee bean, castor bean,egg, garlic, and mushroom dusts

Chemical/industrial latex proteins, isocyanates, metals,resins, dyes, and drugs


source dust samples in the immediate vicinity of a given building may becompared to dust collected indoors. Where symptoms indicate a probableexterior source, some of the occupants may also be tested with the aid of amedical doctor.

Of the chemical/industrial sources, latex protein analysis can be per-formed by immunoassay of a patient’s blood. Drug dispersion sampling isoften performed in house by the pharmaceutical company laboratories, andthe other chemicals can be sampled/analyzed as chemicals (not allergens)and compared with published reference limits for toxicity and sensitizationlevels.

Natural rubber latex proteins (produced from the sap of the Hevea brasiliensis trees) cause dermatitis to many of those who wear latex gloves, par-ticularly to those in the medical professions where frequent use of the glovesis required. The frequent use and replacement of these gloves in an operat-ing room are reputed to be the potential source of airborne latex proteinsin the operating rooms. Of considerable concern, airborne latex proteins inan operating room, where the patient’s system is accessible, may result inanaphylactic shock and possible death if the patient is already allergic tolatex proteins. Another surprise use and source of airborne latex proteinshas been reported in fireproofing material sprayed on structural membersof buildings.

In one case, analysis of the fireproofing insulation was performed. Theconcentrations of latex protein were 1000 to 2000 nanograms per gram ofmaterial (ng/g). Samples of blood were taken from 36 occupants, and 4 testedpositive. The dust tested positive (5 to 26 ng/100 cm2), and the airborne con-centrations ranged from nondetectable to 16 ng/m3. The only confirmationof the latex allergens as being the cause of skin rashes and other allergicreactions was remediation that led to elimination of the symptoms. Althoughthere were no controls, the latex-containing fireproofing was implicated asthe probable source of building complaints.24

Summary

Animal allergens that can be identified by the immunoassay methods dis-cussed herein are limited. The investigator should be aware of those thatare possible and those that can be analyzed. For those that cannot be ana-lyzed by immunoassay, the author suggests forensic dust analysis or guilt byassociation. For instance, if there are bats residing within a building and theoccupants are experiencing allergy symptoms, the investigator may seek toconfirm by forensic dust analysis the presence of insect parts and pieces. Seethe cover of this book for a photomicrograph of bat guana.


References

1. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), pp. 134–37.2. Borror, D.J., and D. DeLong. Introduction to the Study of Insects, 3rd ed. Holt,

Rinehart and Winston, New York (1971), pp. 634–637.3. Halsey, J.F., and M. Colwell. Allergy Basics for IAQ Investigations. (Handout)

Professional Development Course, American Industrial Hygiene Conferenceand Exposition (May 20, 1995).

4. Lintner, T.J., and K. Brame. The Effects of Season, Climate, and Air Conditioningon the Prevalence of Dermatophagoides Mite Allergens in Household Dust.Journal of Allergy and Clinical Immunology. 91(4):862–7 (April 1993).

5. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), pp. 138–39.6. Ibid., pp. 151–53.7. Lintner, T.J. Topics on Allergens (Oral communication). Vespa Laboratories,

Spring Mills, Pennsylvania (October 1995).8. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), p. 154.9. Jones, R.B., et al. The Effect of Relative Humidity on Mouse Allergen Levels

in an Environmentally Controlled Mouse Room. American Industrial Hygiene Association Journal. 56:398–401 (1995).

10. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), pp. 154–55.11. Halsey, J.F. IBT Reference Laboratory, Specializing in Environmental Allergen Testing

(Bulletin). IBT Reference Laboratory, Lenexa, Kansas. pp. 2–3.12. Sylvania. Black Light Radiant Energy (Engineering Bulletin 0-306). Sylvania,

Danvers, Massachusetts (1996).13. Halsey, J.F., and M. Colwell. Allergy Basics for IAQ Investigations (Handout),

Professional Development Course, American Industrial Hygiene Conferenceand Exposition (May 20, 1995).

14. Lintner, T.J., et al. Sampling Dust from Human Dwellings to Estimate the Prevalenceof Dermatophagoides Mite and Cat Allergens. Aerobiologia. April 10(1):23–30(1994).

15. Barbee, R.A., et al. Longitudinal Changes in Allergen Skin Test Reactivity ina Community Populations Sample. Journal of Allergy and Clinical Immunology.79:16–24 (1987).

16. Pope, A.M., et al. Indoor Allergens: Assessing and Controlling Adverse Health Effects.National Academy Press, Washington, DC (1993), p. 52.

17. Chapman, M.D., et al. Monoclonal Immunoassays for Major Dust MiteAllergens,Der p 1 and Der f 1, and Quantitative Analysis of the Allergen Content of Miteand House Dust Extracts. American Academy of Allergy and Immunology. 80:184–94(1987).

18. Trudeau, W.L., and E. Fernandez Caldas. Identifying and Measuring IndoorBiologic Agents. Journal of Allergy and Clinical Immunology. August 94(2)2:393–400 (1994).

19. Platts Mills, T.A.E. Allergen Standardization. Journal of Allergy and Clinical Immunology. 87:621 (1991).

20. Schou, C., et al. Assay for the Major Dog Allergen, Can f 1: Investigation ofHouse Dust Samples and Commercial Dog Extracts. Journal of Allergy and Clinical Immunology. December 88(6):847–53 (1991).


21. Burge, H.A. Bioaerosols. Lewis Publishers, Boca Raton, Florida (1995), p. 135.22. Twiggs, J.A., et al. Immunochemical Measurement of Airborne Mouse Allergens

in a Laboratory Animal Facility. Journal of Allergy and Clinical Immunology. 69:522(1982).

23. Trudeau, W.L., and E. Fernandez Caldas. Identifying and Measuring IndoorBiologic Agents. Journal of Allergy and Clinical Immunology. 94:393–400 (1994).

24. McCarthy, L.F., K.M. Coghian, and D.M. Shore. Latex Allergen Exposures from Fiberproofing Insulation. Presented paper under the heading of Indoor Air Qualityat the American Industrial Hygiene Conference (May 22, 1995), p. 6.

Section V

Building Systems and Materials

275

16HVACSystems

Overlooked and underappreciated, the heating, ventilation, and air condi-tioning (HVAC) system is the heart and blood of a building. It is the centralconveyance of all indoor air contaminants. It may capture and entrain out-door pollutants. It may be the source of poor indoor air quality, or it mayprovide the means for improving indoor air quality.

HVAC systems are designed to provide air exchange, air cooling/heating,and air distribution throughout a building. Sometimes indoor air qualityand HVAC design and maintenance are in conflict. The purpose of this chap-ter is to present the basic concepts, describe inspection abnormalities, pro-vide a means for HVAC system sampling, and afford a means whereby thisinformation can be assimilated for use in an action plan.

The Basic Design1, 2, 3

A basic HVAC system consists of temperature controls, a fan to move theconditioned air, air filtration media, heating/cooling coils and condensatedrip pan, a heat exchange condenser, and a distribution system (e.g., ducting,air supply louvers, and return air grills). The simplest of these is the residen-tial HVAC system.

A typical residential HVAC consists of a return air damper, a filter, cool-ing/heating coils, condensate drain pan, and fan—all of which are housedin an HVAC closet. The condenser, generally located outdoors, circulates aheat exchange fluid (e.g., refrigerant) to and from the cooling/heating coils.Most residential units do not provide for outdoor air. Thus contaminated airis returned back into the conditioned spaces of a home. In these cases, theonly means of diluting the indoor air where there is no outdoor air intakeis through doors, windows, and structural leaks. The tighter the building,the less air exchange is likely to occur. Also of note, residential units haveremote heat exchange condensers with insulated condenser-to-unit convey-ance line.


Commercial, institutional, and some larger home systems are either similarto that of a typical residence yet housed in a mechanical room, or the HVACunit is “unitized” as an all-in-one package. Mechanical rooms often serveas a return air plenum (i.e., mixing box or chamber), and, once again, com-ponents are separate—particularly the heat exchange condenser. Separationof components may result in heating/cooling losses when conveyed to theconditioning coils at a remote location.

Unitized units are typically rooftop units (some enclosed within a rooftoppenthouse). See Figure 16.1. The unitized units are all in one with the excep-tion of the distribution system. They are more efficient than the units withthe separate heat exchange condensers.

In large volume air spaces, HVAC units may be centralized (e.g., a singleunit) or decentralized (e.g., multiple units). While decentralized multipleunits require less ducting and are less expense initially, the centralized sin-gle units require a more complex means of air distribution, but less mainte-nance is required. Each type of unit has its own problems.

Decentralized multiple units require multiple unit maintenance checks,multiple filter changes, and multiple repairs. Temperature controls are, how-ever, more manageable. An office building with different occupants willgenerally have a separate unit for each office space. Wherein office space isrented, each office is generally responsible for its own HVAC energy costs andmaintenance/upkeep. A maintenance provision is generally in most officespace contracts. This is typically overlooked by the occupant and comes as asurprise to the renter when a problem arises.

Condenser HousingCooling Coils

Heating CoilsFilter(s)

Outside Air Damper

Return Air DuctSupply Air Duct

Blower Fan

FIGURE 16.1Basic design schematic of rooftop air handling unit.

HVACSystems 277

Centralized single unit distribution systems are zoned. Each zone willgenerally have its own temperature controls. Yet if not properly designed,zones can be problematic, especially as conditions change within each zone.Inconsistencies may result as:

• Temperature requirements vary, within a zone, due to increased/decreased occupancy in some areas or introduction of heat-producingequipment (e.g., computers).

• Radiant heat gains and losses create uneven distribution of hot andcold as the sun shifts during the day. This is a common cause of com-plaints in office building. On the west side, occupants complain it’stoo cold in the morning and too hot in the afternoon.

To further complicate and confuse, some level of awareness and knowledgeis prudent when assessing an HVAC system. A single HVAC system mayhave one or several zones, each of which has its own temperature control(e.g., thermostat), and each zone will have its own dedicated air distributionbox. The distribution boxes are sites where dust, air contaminants, and mois-ture can and do collect. Distribution boxes are briefly described as follows:

• Constant Air Volume (CAV)—varies temperature of the air deliv-ered to the occupied spaces; temperature is regulated by control-ling delivery of heated and cooled air to a mixing box for each zoneaccording to their requirements; and mixing box may collect, retain,and distribute air contaminants.

• Variable Air Volume (VAV)—varies air volume delivered to theoccupied spaces as demand needs vary by zone; possible failure toreceive adequate makeup air as required by the American Society ofHeating, Refrigerating and Air Conditioning Engineers (ASHRAE)Standard for Ventilation for Acceptable Indoor Air Quality.

• Hybrid Systems—the best and the worst of both CAV and VAV.

Last, but not least, air distribution is generally, not always, through air duct-ing. The duct may be insulated on the interior or exterior. It may be exter-nally insulated flex or metal ducting. It may be fiberglass board that is itselfinsulated. And the air supply duct in commercial units is often insulatedinternally. Should there be leaks in the duct, air movement can draw outsideair (e.g., hot, dusty, insulated attic) into the air conveyance, delivering con-taminants picked up along the way.

The complexity of HVAC systems is much greater than the simple descrip-tion provided herein. The intent has been merely to cover the basics so theinvestigator can visualize and conceptualize the possible impact a poorlymaintained HVAC system may have on indoor air quality. Should you wishto become more enlightened, books on HVAC systems abound everywhere.


HVAC Visual Inspection

The complexity of an HVAC system is such that there are multiple things thatcan go wrong, multiple things that could contribute or add to building-relatedhealth complaints. From stem to stern, inside the units and outside, the pos-sibilities are endless. Herein is a discussion of a few of the possibilities.They are only a start. Understand the system(s) and do not ignore oddities.Investigate and consider all out-of-place items as part of the puzzle. The devilis in the details!

Outdoor Air Intake

The outdoor air intake louvers should be checked. Some are manuallyadjusted and most are computer-operated. It is not unheard of that the com-puter shows the louvers are open wherein upon inspection they are actuallyclosed. If not closed, the intake may be clogged. See Figure 16.2. Do not beoverly surprised to find a cardboard cut-out covering the air intake!

The air intake should ideally have an air filter that filters out the outdoorair that mixes with the air return—after the return air has been filtered. Inother words, if the intake air is not filtered or minimally filtered (e.g., MERV 4disposable fiberglass filter), most of the outdoor dust and debris will becomeentrained in the HVAC system. As the U.S. Environmental Protection Agency(EPA) National Primary Ambient Air Quality Standard for outdoor total

FIGURE 16.2Rooftop air intake louver—open 100 percent with some collection of debris. (Courtesy ofOmega Southwest Consulting, Canyon Lake, Texas.)

HVACSystems 279

particles (75 µg/m3) exceeds the Leadership in Energy and EnvironmentalDesign (LEED) acceptable limit for indoor total particles (50 µg/m3), clearlyunfiltered outdoor air can contribute to or be the source of poor indoor airquality.

In commercial and high-rise office buildings, measure and calculate theamount of outside air intake in terms of cubic feet per minute (CFM) perperson. The CFM per occupant should comply with the latest ASHRAEStandard for Ventilation for Acceptable Indoor Air Quality.

Outdoor Air in the Vicinity of Air Intake

Investigate the area(s) around the HVAC air intake for bird (e.g., pigeon) and batdroppings, garbage, leaves, and puddles of water. Locate sewer vents, kitchenexhausts, chimneys, and cooling towers within the vicinity of the air intake.There is no magic number to define “vicinity.” Use good judgment based onwind patterns and suspect potential source of complaints and how they mightrelate to times when the louvers are most likely to have been open.

Indoor HVAC Equipment Rooms

Many commercial HVAC units are located indoors in a room that also servesas a return air plenum. It is astonishing how often one will find the samerooms being used as storage for wet, dirty mops, paints, solvents, cleaningfluids, oils, and other delightful surprises. Sometimes the investigator willsee something that just doesn’t look right. “If it looks out of place, it probablyis!” For example, a black stain was observed on top of and at the return entry.It was directly under a fluorescent light fixture that was found to have burned,emptying its product on the air handler. The light ballast contained PCBtransformer fluid that burned and blew the by-products onto surfaces withinthe room that served as a return air plenum. See Figure 16.3. The by-productsof PCB combustion are among the most toxic chemicals known to man (e.g.,polychlorinated dibenzofurans and polychlorinated dibenzodioxins).

Filters

Check the filter bank(s) for effectiveness. What does this mean? Look for gapsbetween filters and around them. Air will follow the path of least resistance.If it can, it will! Air will go around, not through the filter(s). In a filter bank(e.g., multiple filters), the gaps/openings between the filters should be sealed(e.g., aluminum or duct tape). Sometimes filters are installed improperly orare not sturdy enough to withstand the air movement over the filter surface.The result may be a deformed filter. See Figure 16.4. with a large volume ofunfiltered air!

Air filters should be inspected for cleanliness the have been recentlyreplaced, filters are not expected to be squeaky clean, but they should not

HVACSystems 281

immediately after the filter. The residence had recently been crop dustedwith a powderlike pesticide that showed evidence that it had passed throughthe HEPA filter and returned into the breathing zone of the residents. This isan example of a filter “not performing” as intended.

The perceived efficiency of air filters does not always withstand a real-ity check. When asked about the efficiency of a filter in a commercial unit,maintenance personnel will generally look up the efficiency that may saythe filter is 95 percent efficient, but looking further, the efficiency on the specsheet is based on a wide range of particle sizes. In reality, maybe the boulders(greater than 10 microns in diameter) are captured, but the fine particles findeasy passage. The Minimum Efficiency Reporting Value (MERV) rating isthe most commonly accepted system and should be sought wherever pos-sible. See Table 16.1. Not all filter manufacturers volunteer the MERV ratingwithin their specification sheets.

FIGURE 16.4Multiple filters in large commercial HVAC—deformed filter allowing unfiltered air to passthrough.


Condensate Drain Pan

Inspect the condensate drain pan. It should be free of standing water, or atleast it should be in the process of draining as the chilled water condensates.If the air conditioning unit is not operating or there is standing water thatdoes not appear to be draining, either the drain is plugged or the drain panis not leveled to allow for drainage. See Figure 16.6. Standing water is a safehaven for mold and bacterial growth.

In colder months when the heater is operating, evidence of poor waterdrainage during the summer months is a rusted, dirty drip pan. Observethe pattern of the rust. If drip pan level is a problem the rust stain will serveas an indicator of that which was and that which will be again. Where therust is even, all the way to the top of the pan, there is or was likely a cloggeddrain. Where the rust is uneven, away from the drain line, the pan is likelynot properly leveled.

In commercial units, maintenance often places biocide tablets in the drippan to minimize microbial growth. These are often dropped into the drippan and forgotten. Biocide tablets come with instructions. These instruc-tions generally include a refresh/change schedule (e.g., monthly). They arerarely read or followed. The presence of an empty container or deteriorated

FIGURE 16.5Hospital bag filter—caked on dust/debris at upwind side with evidence of damage, moldgrowth, and debris on the downwind side of the filter.

HVACSystems 283

TABLE 16.1

MERV Rating Summary

Residential Filters (MERV 1 to 4)MERV 1 (e.g., self-charging woven panel filter)

Arrestance: 65%Spot efficiency: <20%Controls: carpet fibers

MERV 4 (disposable fiberglass or synthetic panel filter)Arrestance: 75–80%Spot efficiency: <20%Controls: >10 microns

Commercial Filters (MERV 5 to 8)MERV 5 (e.g., disposable synthetic panel filter)

Arrestance: 80–85%Spot efficiency: <20Controls: cement dust

MERV 8 (e.g., disposable extended surface area pleated filters)Arrestance: 30–35%Spot efficiency: >90%Controls: 3.0–10.0 microns

Hospital Labs, Better Commercial, and Superior Residential Buildings (MERV 9 to 12)MERV 9 (e.g., rigid cartridge filters 6 to 12 inches deep)

Arrestance: 40–45%Spot efficiency: >90Controls: welding fumes and auto emissions

MERV 12 (e.g., nonsupported microfine fiberglass or synthetic media)Arrestance: 70–75%Spot efficiency: >95%Controls: 1.0–3.0 microns

Superior Commercial Buildings and General Surgery (MERV 13–16)MERV 13 (e.g., rigid cartridge filters 6 to 12 inches deep)

Arrestance: 89–90%Spot efficiency: >98Controls: fine aersols such as sneezes

MERV 16 (e.g., nonsupported microfine fiberglass or synthetic media)Arrestance: NASpot efficiency: NAControls: 0.3–1.0 microns

Carcinogenic, Pharmaceutical, Radioactive Materials, and Cleanrooms (MERV 17 to 20)

Note: Partial list, shows range of MERV ratings in each functional filter types.


canister is an indication of acknowledged water excesses in the drip pan andan easy fix in place of leveling the pan.

Fan Housing

The fan blades within the fan housing move the air. Subsequently, whatever airpasses through the HVAC will leave a forensic trace of all substances—largeand small. The fan belt deteriorates with time, and rubber particles are likelyto be a portion of the dirt and dust found on the fan blades and on the outsideof the housing. See Figure 16.7. The fan blades are a great collector of materialthat can later be analyzed as if it were a crime scene. Follow the evidence!

Unit and Duct Liner

Chilled water blow-over to the downwind side of the HVAC unit is commoneven in the best of units. A dust covered liner generally contains organic matter(e.g., skin cells)—a meal for the molds; the liner gets wet—water for the molds.The outcome is a feltlike carpet of growing mold. There have been report casesof the happy meal deal wherein an investigator did not look at the HVACsystem. He/she found water penetration into the wall cavities of a buildingwith moisture and mold growth in the wall cavity, and stopped the search formold. Having found one source of mold growth, the environmental profes-sional didn’t go any further. The investigator felt they had found “the cause”

FIGURE 16.6Residential HVAC—water staining around the base of the unit caused by overflow of drippan.

HVACSystems 285

of the elevated mold spores, ignoring the possibility that there may be multiplesources, multiple causes, and the HVAC system is ignored.

A tragic example of an ignored HVAC is a 20-story office building wherethe occupants were complaining of severe allergies. An environmental con-sultant investigated and found high mold counts in the occupied spaces andmoisture in the wall cavities associated with leaks in the caulking aroundthe marble exterior of the building. Remediation cost around $750 million,and still complaints persisted. The consultant figured that the cause wasmold in the wall cavity that was escaping from around the wall sockets. So,they persisted in monitoring the wall cavities with no definitive findings.The mold counts still remained high. Another consulting firm investigatedthe HVAC system and found a carpet of mold growth in the HVAC liner.Corrective action was taken, and the indoor air mold counts dropped from2000 counts/m3 to 200 counts/m3. Although there had been no remediation

FIGURE 16.7Fan housing—collection of dust and dirt from air.


on the monitored wall cavity, the fix on the HVAC liner was the silver bullet.The complaints subsided!

Let’s go one step further. High humidity can wreak havoc on an entireHVAC system. This occurs where there are no humidity controls or poorlydesigned humidity management systems in a high humidity environment.The evidence is different and distinct from chilled ware blow-over which isgenerally limited to the water impacted areas of the liner. When high humid-ity is the culprit, all liner surfaces (e.g., bottom, sides, and top of the unit andduct) will have a merry display of mold growth. See Figures 16.8 and 16.9.Caution! Do not make the assumption that all ducting is affected. Whereasthe supply air duct is covered with mold growth, the air return may not be.Inspect them separately!

Supply Registers and Return Air Grills

Supply registers are generally the telltale sign of problems from within or con-veyance of contaminants through the HVAC system. Return air grills will usu-ally have less of the same as that which is supplied and will be diluted downas the air returns to the air handler. This scenario, however, is not an absolute.Wherein it is drawing in contaminated air directly from the source (e.g., copymachines), the air return grill may display more dirt than the air supply regis-ters. The registers and grill are only signs. A deeper investigation is indicated!

In one instance, there was a disconnect, hole in the air duct through whichmineral wool insulation was drawn into the air stream, conveyed to the air

FIGURE 16.8Residential HVAC system—high humidity causing mold growth on unit liner and air supplyducts.

HVACSystems 287

supply register. The appearance was that of gray dust monsters, swaying over-head from the registers. Black powderlike deposits are often interpreted byoccupants as the “black mold” wherein it may be shredded fan belt pieces.

Dirt around registers and grills are symptoms. See Figure 16.10. Thesource(s) must be investigated. Contaminants are the clue, and sampling isa must.

FIGURE 16.10Dirty air supply register—water stain around edge.

FIGURE 16.9Commercial HVAC system—high humidity causing mold growth on unit liner.


Level of Maintenance

Evidence of poor HVAC maintenance should set off alarm bells. Some of thesigns include, but are not limited to:

• Reduction in energy efficiency• Rips and tears in the liners• Dirty, clogged cooling coils• Frozen chilled water line (see Figure 16.11)• Used HVAC supplies (e.g., fan belts) left inside air handler• Dirty-and-beyond filters (see Figure 16.12)• Tools and equipment stored in an air handler• Rust, dirt, and debris buildup inside the units

FIGURE 16.11Mobile home HVAC unit—frozen chilled water line and condensate water draining throughthe floor in the bottom of the unit.

HVACSystems 289

• Appearance of a slime or fuzzy growth• Dirt, damage, and moisture buildup• Condition of the fan belt and motor• Debris, dirt, and damage to the fan blades (e.g., broken fan blades)• Air deodorants in air supply systems (e.g., disguise odors)

Most residential and some commercial HVAC systems have filter(s) inthe return air grill. There is rarely a problem associated with the returnsunless they are forgotten and ignored. In an office building with strangeisolated niche areas of building-related health complaints, an enclosedoffice where the occupant had severe health complaints was found tohave a return air filter that appeared never to have been changed. The fil-ter was so old it had deteriorated to nothing more than a skeleton, a merethread of its original existence. Dust, dirt, and debris collected aroundthe old filter, and droppings were recycled, becoming part of the officeair quality.

Air Duct

Air duct conveys all that precedes it. If there is a problem upstream, it islikely to be downstream.

There may be damaged, leaking air duct that could result in collection.Leaking duct systems pick up contaminants along the way.

FIGURE 16.12Wet, dirty filter—caked with dirt, debris, and mold growth.


The air duct to supply register connection may be loose or completelydetached. Air blowing in the space around the supply register could result incondensation around the register or elevated dust levels from within the attic.

Sometimes the air duct is not just a conveyance for air but for varmints.Rodents and rodent dropping have been found in air ducts. There was even onereport where an inspector went face-to-face with a snake—inside the air duct.A homeowner saw a paw reaching down from one of the air supply registers.Fearing the worst, brave soul that he was, he let it stay there until he could berescued by the professionals. They found a very hungry, very angry raccoon.“Don’t be surprised at what might be lurking in them there air ducts!”

Strategy and Sampling

Most environmental professionals who investigate HVAC systems are search-ing for mold growth. Yet while mold growth is the most commonly encoun-tered assailant in HVAC systems, there may be a worm or two in the pile.

Investigation is first and foremost. Seek and ye shall find. If somethinglooks strange and it can be sampled—sample it. If something looks out ofplace and it can be sampled—sample it. If you think you know what it is andit can be sampled—sample it.

Surfaces within and around the HVAC system may harbor suspect mate-rial. Whereas contaminants may be distributed into occupied air spaces, mostdistribution substances will be growing on, deposited, and retained on thesurfaces. Thus forensic surface sampling, the simplest approach, is in order.

The most direct, easiest form of surface sampling is the “clear tape” method.This approach involves the following:

• Dispense a 2- to 3-inch-long strip of clear tape (e.g., Moore CrystalClear).

• Loosely hold the ends of sticky side between your thumb and fore-finger with sticky side facing out, away from your hand.

• Lightly touch, only once, the surface you want to sample. As somesamples are fragile—DON’T PRESS THE TAPE TO THE SURFACE.Just touch the surface!

• Lift the tape and stick it to a surface for transport to a laboratory (e.g.,thick plastic zip-lock baggie or microscope slide).

• Label the transport surface with an alpha/numeric identifier.• Log sample location, identifier, sample date, and other pertinent

information (e.g., appearance, conditions, photo number, etc.).• Fill out chain of custody information, and ship to a mold or foren-

sic laboratory.

HVACSystems 291

A single lift represents quantifiable material (e.g., mold spores) per surfacearea (e.g., square inch). Multiple lifts from several areas are used for identifi-cation only, but too much sample may obscure, obstruct analysis. So whereina larger sample size is required and the surface dust cannot be scooped up,micro-vacuuming is another option.

Micro-vacuuming requires the use of an air sampling pump and filter. Thesampling pump acts as a miniature vacuum. The attached filter serves as thevessel. This method is as follows:

• Using plastic tubing, connect a filter (e.g., polycarbonate, glass fiber,or mixed-cellulose ester membrane filter) cassette to either a low-volume or high-volume air sampling pump. FLOW RATE IS NOTIMPORTANT. However, the higher the air flow, the better will bethe collection.

• Decide on the area you wish to sample, and create a template thatcan be clean or discarded between samples. The most common tem-plate size is 4 inches by 4 inches (or 10 cm by 10 cm).

• Lay down the template and vacuum the area within.• Label the cassette with an alpha/numeric identifier.• Log sample location, area sampled (e.g., 100 cm2), identifier, sample

date, and other pertinent information (e.g., appearance, conditions,photo number, etc.).

• Fill out chain of custody with the sample info and area information,and ship to a mold or forensic laboratory.

The preceding sampling methods have been for surface sampling of rela-tively dry areas. For thick, caked-on, wet surfaces and for water samples(e.g., drip pan water), bulk material collection may be collected in a vial. Thisapproach simply involves scooping up a sample into a collection container.Protective latex or vinyl gloves should be used during the collection of anymaterial that you may contact with your hand (e.g., scooping up water).Water samples should fill the container to the top and be sealed to preventleaks. Don’t withhold or limit the thick, caked-on samples, and collect at leasta teaspoonful. In a pinch, if you don’t have access to laboratory suppliedsampling vials, you may use a film container or unused medicine bottle andseal them with electrician’s tape. The laboratory will weigh the sample(s) andprovide results in type of material per gram or measure the liquid weight orper volume of liquid with results reported in term of material per ounce. Login the appropriate information, fill out the chain of custody, and ship to thelaboratory.

Last but not least, one may cut out a portion of the air handling unit inte-rior lining or fiberglass duct. Cut it out or tear it out and place in a zip-lockbaggie or vial. Protective gloves should be worn, and all should be properly


documented as in the preceding methods. Analysis will be reported in mate-rial per weight.

Analyzing the Unknown

The environmental professional will have speculated as to the possible com-ponent of material encountered in and sampled from within the HVAC sys-tem. More often than not, speculation will be the infamous “mold spores”and mold growth. In this case, samples may be analyzed by one of manymold laboratories. At that time, the samples should be analyzed for moldspores and growth.

If, however, the investigator wants to go a little further, a forensic labora-tory is in order. Many of the mold laboratories are able to identify most pollenand some allergens in a generic sense. But if you want a better breakdown,“forensic laboratories” can identify not only particles (e.g., fan belt rubber)but sometimes chemicals that are adsorbed onto the surface of the particlesas well as metal deposits (e.g., deteriorating components), fibers (e.g., resincoated fibers), animal urine, plant matter, and minerals. Forensic laborato-ries are a rare breed. So if a mold laboratory says they can perform forensicanalysis, let it be known that they are limited. A true forensic laboratory willparticle pick (or pick through the sample material under a microscope witha very fine probe) and can identify all components. This is a very expensiveproposition and is often the last resort.

Then, too, if the investigator suspects a specific chemical or substance, thesurface sample (excepting the tape sample) can be analyzed by an indus-trial hygiene/environmental laboratory. This analysis is less expensive thanforensic analysis, but it fails to include “all possibilities.” All possibilitiesmay be an absurd effort in futility, while a narrow focus may be just whatthe doctor ordered.

Interpretation Not So Simple

The mold spore and growth surface analysis is generally reported in termsof amount and type of mold spores (less than 10 percent coverage) in a com-posite as well as amount and type of mold growth (e.g., 80 percent coverageof Cladosporium).

As for other surface materials, the environmental professional may beseeking confirmation or denial of a specific contaminant already identi-fied in the air within the occupied area(s). There may be a witch hunt—if

HVACSystems 293

a previously identified contaminant is in the HVAC system, where is it?How bad is it? Is it in the air supply? Is it in the air return? For instance, apesticide was crop dusted by an applicator inside a residence. A remedia-tion firm cleaned all surfaces and furnishings, but they did not clean theHVAC unit. Upon inspection, a fine white powder was found inside the airhandler immediately beyond a high efficiency box air filter. If the filter hadbeen operating as it should have been, the pesticide should not have gottenthrough. There was a possibility that the white powder was sheet rock dustfrom construction that got into the air handler prior to putting the filter inplace. The intent of the surface sampling had been to determine if the whitepowder was a pesticide or sheet rock. The finding was that the powder wasindeed sheet rock dust.

Summary

This chapter speaks to inspections more so than sampling of HVAC systems.Wherein the HVAC system is the single most conveyance of contaminantsin a building, it is all too often ignored or overlooked. Spend the big buckscleaning up visibly contaminated building materials, complaints temporarilydissipate only to return with a vengeance. Why? The conveyor of all thingsairborne has been overlooked. Always consider the HVAC system. A visibleinspection at the least should be conducted in order to identify anything thatjust doesn’t look right. It is a terrible thing to boast that you have identifiedand fixed a problem—only to find the problem still persists.

295

17SewageSystemsandSewerGases

In the mid-1800s, London’s sanitary reform leader Edwin Chadwick com-mented, “All smell is disease.” Subsequently, the last half of the 19th centurywas dedicated to designing drainage systems and “sewer traps” to preventthe noxious gases from entering into homes. Societies further believed thestench made people feel ill, lowering their resistance to disease—a predis-posing factor to illness.

In 1881, after President James Garfield was shot by an assassin and takento the White House for treatment, a “well-known plumber” told a NewYork newspaper that “the real trouble is sewer gas.” The unsanitary medi-cal care Garfield received was considered a secondary cause in his even-tual death eleven weeks later, two weeks after being moved to his NewJersey home. The Sanitary Committee of the Master Plumbers of New Yorkoffered to outfit the White House with sewer traps at no charge. Garfield’shorrified successor, Chester Arthur, refused to move into the White Houseuntil the plumbing was reconstructed to eliminate the sewer gas, going sofar as to insist the White House be torn down and replicated with a sewergas–proof replica in its stead—a project that would have cost $300,000(nearly $7 million in today’s dollars). The Senate approved the expense, butthe House of Representatives refused. President Arthur had to settle for aplumbing overhaul instead.

It wasn’t until the advent of the 20th century that public health officialscame out and stated that the danger of disease from sewer gases is “nolonger a plausible hypothesis.” Although sewage waste remains a concernin regard to transmission of disease, the noxious gas is not thought to bea carrier.

Plumbers had found a profitable niche in the building industry, anddespite advances in the 20th century, problems still rear their ugly head—inold homes and in newly constructed residences. Yet the older the home, themore likely sewer gases will arise to torment building occupants.


Occurrence of Sewer Gases

Raw sewage consists of everything flushed down the toilets and washeddown the drains. Residential sewage typically contains everything fromsoap to human excrement, detergents, cleaning solvents, grease, food waste,and any of a number of unknowns. Industrial and commercial sewage haveall that which is encountered in residential sewage and much more.

Hazardous Gases

The anaerobic decomposition of raw sewage in a septic system or sewageline produces “sewer gases.” Sewer gases are predominantly hydrogen sul-fide and methane—both flammable. Other gases include ammonia, sulfurdioxide and nitrogen oxides. The “rotten egg” odor is generally associatedwith hydrogen sulfide, but the noxious “sewage odor” can be a mixture ofhydrogen sulfide, ammonia, sulfur dioxide, nitrogen oxide, and occasionalunknowns.

Methane does not have an odor. It is not uncommon for building occu-pants say, “It smells like methane.” Why? They have been told there is meth-ane gas in sewers. Some say, “It smells nasty.” Or, “It stinks.” Interpretation,“It smells like sewage!” Yet sewer gases can be more than just an obnoxiousodor.

If allowed to decompose long enough in a confined space (e.g., cloggedsewer line or septic system), sewer gases can become an explosion haz-ard. For instance, there have been reports of septic cleanout operatorslighting a cigarette during the pumping process and receiving a flashburn to the face as the flammable gases built up at the access hole. Therewas one report of a homeowner who built a brush fire on top of his septictank that somehow resulted in a “sewer gas explosion” that rocked theentire neighborhood.

Health complaints associated with sewer gases include nervousness, diz-ziness, nausea, headache, and drowsiness. Low-level exposure to the hydro-gen sulfide gas component causes irritation of the eyes and respiratory tract.Methane and carbon dioxide (by-products of bacterial degradation of sew-age) are an asphyxiant (displace oxygen in air)—when encountered above1 percent. This would be rare, occurring when gases have been trapped.Ammonia, having a strong pungent odor, causes eye and mucus membraneirritation. Sulfur dioxide and nitrogen dioxide are irritants as well. SeeTable 17.1. The irritants are unlikely to be present in the sewer gases at anysignificant levels so as to cause acute toxicity, but their odors will contributeto the overall sewer smell along with all other nonhazardous odors associ-ated with human waste.

SewageSystemsandSewerGases 297

Biological Components

Sewage contains naturally occurring bacteria and microbial pathogens thatmay pass through the alimentary system. The naturally occurring bacteriaare coliforms and E. coli. On the other hand, fecal pathogens are associatedwith diseased people. They include a wide variety of bacteria, viruses, proto-zoa, and parasites. Although not generally airborne, many of these have thepotential for causing serious illness or death in infants, elderly people, andimmuno-compromised individuals if airborne exposures should occur in arare circumstance. For instance, sewage may backflow into or cross-contam-inate an air handling system—unlikely, but certainly anything is possible!

Noxious Odor Confusion

Odors and health effects of sewer gases can be confused with mold and nox-ious chemicals within a structure. Sometimes there is no immediately appar-ent association between slightly detectable “stinky” odors and sewage suchas in a case whereby sewage gas leaked into an air duct and was dispersedthroughout the occupied space(s).

In an indoor air quality investigation, sewer gases are occasionally overlookedespecially when unpleasant odors are not emanating from a bathroom and theoccupant(s) are convinced the odor’s source is elsewhere. For this reason, sewergases should be considered wherein there is a complaint of “noxious odors.”There are steps an investigator can follow when sewer gases are suspect.

TABLE 17.1

Sewage Gas Exposures

Sewage GasesACGIH

TWA (ppm) Odor

Odor Thresholda

(ppm)Low-Level Exposure

Warning Signs

hydrogen sulfide 1 rotten eggs 0.0045 irritation of eyes andrespiratory tract

ammonia 25 pungent,irritating

17 irritation of eyes,mucous membranes,and skin

sulfur dioxide 2 sharp,irritating

2.7 irritation of eyes,mucous membranes,and skin

metallictaste

nitrogen dioxide 3 bleach 0.12 upper and lowerrespiratory tractirritation

nitrous oxide(“laughing gas”)

25 – – upper respiratorytract irritation

a Lowest accepted odor thresholds.


Investigation Procedures

Sewer gases can leak anywhere along the sewage lines and vents, get trappedin the sewage system, and re-enter a building from outside. The cause andsource of complaint(s) may be multiple leaks, improperly or failed systems,or they may be a single sewer gas leak in conjunction with other air contami-nants disassociated from the plumbing. To address these complex issues, theinspector may: (1) confirm and track sewer gases by air sampling; and (2)perform a limited visual inspection for sewer system discrepancies.

TABLE 17.2

Pathogens Encountered in Fecal Material

BacteriaGram negative bacteria may cause diarrhea, fever, cramps, and sometimes vomiting,headache, weakness, loss of appetite, and other enteric symptoms. Some of the pathogenicbacteria and diseases associated with fecal material include:• E. coli (virulent and nonvirulent strains)—virulent E. coli infections result in severe

stomach tenderness and cramps, watery diarrhea (later bloody), nausea, and vomiting.• Shigellosis—abdominal pain, fever, bloody stool, rectal pain, nausea, vomiting, and

watery diarrhea.• Typhoid fever—rash “rose spots” on belly and chest, abdominal tenderness, agitation,

bloody stools, chills, confusion, difficulty paying attention, delirium, fluctuating mood,hallucinations, nose bleeds, severe fatigue, lethargy, and weakness.

• Salmonella infections (most common foodborne illness)—diarrhea, abdominal cramps, andfever.

• Citrobacter infections—associated with nosocomial infections, particularly in debilitatedpatients, and in infants may cause meningitis and brain abscesses.

• Cholera—watery diarrhea (fishy odor), abdominal cramps, dry mucus membranes ormouth, dry skin, excessive thirst, glassy or sunken eyes, lack of tears, lethargy, low urineoutput, nausea, rapid dehydration, rapid pulse rate, unusual sleepiness or tiredness,vomiting.

• Many others

Viruses

HepatitisLiterally hepatitis means inflammation of the liver. Hepatitis caused by a virus is known asviral hepatitis. When hepatitis is a result of sewage backup, it is often characterized byinflammation of the liver and jaundice.

Protozoan

Cryptosporidium and giardia lamblia may cause diarrhea and stomach cramps, and evennausea or a slight fever.

Parasites

Roundworm (ascariasis)—most people have no symptoms. With a lot of roundworms, youmay cough and have trouble breathing, or you may have pain in your belly due to ablocked intestinal tract.


Air Sampling

The components most frequently encountered in sewer gases are hydrogen sul-fide and methane. Although is may seem fairly straightforward, air samplingfor the purpose of identification and tracking of sewer gases can lead to falsenegatives, confusion, loss of time, and unnecessary laboratory expense. Forexample, an inexperienced investigator rushed to the rescue where occupantswere complaining of sewer odors. He collected the noxious air in an evacuatedSumma® canister and sent it to a laboratory for analysis by gas chromatography/mass spectrometry (GC/MS). This analytical method is not only expensive, butit is a poor detector for both methane and hydrogen sulfide gas. Not only did heinform the client that the laboratory told him that the “source” of the problemwas sewer gases, but he continued to insist that the odor was methane (whichwithout additives has no odor). The occupants were horrified as he persisted totell them methane was a “flammability hazard.”* Ultimately, he was able to trackdown the sewage leak by destructive inspection of walls and ceilings with thehelp of a plumber.

Many misunderstandings and much confusion can be avoided by simplyunderstanding the air sampling methods—not to be confused with taintedChinese drywall and natural gas leaks.

Natural gas is predominantly methane, and it is laced with low levels of anodorous gas such as mercaptan gas that has a skunklike odor. Air samplingmay be performed for the purpose of identification and sometimes for track-ing the source of a sewage system leak.

Identification of Components

Sewer gas confirmation can be accomplished by collecting air by evacuated can-isters or ambient air sampling bags (e.g., Tedlar® bags). Analysis should then beperformed separately for the principal identifiers. The best recovery, most accu-rate analytical method for methane is GC/flame ionization detector (FID).

As for the hydrogen sulfide, laboratories may vary. EMSL analytical with-draws air from the canister or bag and analyzes the suspect air by using aDrager Chip Measurement System (CMS) that has a 0.25 ppm detection limit forhydrogen sulfide. This CMS, not an inexpensive piece of equipment, can also beutilized for field grab sampling. Another approach, slightly more costly but hav-ing greater detection, is extraction of a headspace sample and analysis by GC/SCD. The hydrogen sulfide detection by GC/SCD is 0.005 ppm. Each of thesecombined analytical approaches is cheaper and more accurate than GC/MS.

Tracking Sewer Gases

Tracking hydrogen sulfide and methane gases may be accomplished usinga real time confined space entry monitor with both hydrogen sulfide (e.g.,

* It takes days of sewage gas confinement for decomposition and off-gasingsufficient to create combustible levels of sewer gases (e.g., methane).


photo-ionization detector) and combustible gas detection (e.g., Wheatsonebridge). Although the odor of hydrogen sulfide gas is detectable at levelsmuch less than the detection of most field equipment, direct reading instru-ments can be helpful in “tracking” the source—if the source is producingambient hydrogen sulfide or methane levels in excess of the detection limitsfor the instrument. The MultiRAE detection level for hydrogen sulfide is 1ppm, and it is 1 percent of the LEL (Lower Explosive Limit) for combustiblegases (e.g., methane). Methane has an LEL of 5.5 percent. A measurement of1 percent LEL methane would be 550 ppm.

Sewage System Inspection Awareness

Inspections are generally performed by a licensed plumber—if a leak is sus-pect. If, however, a leak is not suspected by the occupant(s), the experiencedenvironmental professional should be aware of the possibilities in order tounderstand and track the source. All too often the bad odor association withsewer gases and plumbing leaks/failures are not even considered for lack ofunderstanding as to the complex nature of plumbing problems. Air move-ment within a building is complex, and sewer gas leaks may not be blaringlyapparent.

An abandoned waste line may still be connected to the main waste lineand has not been capped off. In a crawl space or wall cavity, the sewage orgases may enter the living space through wall or floor penetrations.

Drain waste vents and sewage lines may be clogged. Trapped gases may buildup and sewage may back up. Gurgling heralds a backlash of the “nasties.”

Re-entrainment of air from the roof vents and leaks/failures in septic/sewerlines outside the building could enter a building through doors, windows, andstructural cracks. Re-entry into a structure may be caused by wind or heat.

Stories abound, things happen! A basic awareness of plumbing faults andfailures may add significantly an investigator’s bag of tricks.

Poorly Installed Sewer Vents

Sewer vents may be inadequate or missing. On the roof, a vent should bevertical to the horizon, not to the roof. If a vent is sticking out of the roof atan angle, something is wrong.

A plumbing vent should stick out above the roof, not on the side wall—nextto a window or door. If located anywhere than on the roof, it is not right.

Closed-off or blocked vents will result in sewer gas backups into a build-ing. Blockage may occur due to the presence of wasp nests, birds’ nests,rodents, and dead animals.

A plumbing vent may have all the appearances of having been properlyinstalled, but it may not be connected or improperly connected. Sewer gaseswill then leak into the roof or wall cavity.


The fly-by-night plumber may not install any plumbing vents. With novents, sewer gases will re-enter through a sink or shower trap. If there are novents on a roof, be suspicious!

Then, too, some plumbers terminate plumbing vents in the attic or a wallcavity. Not all structures, particularly in the country, are built to code. Novents on a roof are a telltale sign.

Wherein too short above the roof, a plumbing vent is likely to get blocked bysnow and ice in freezing climates. Then, too, if it is of adequate height, the ventmay still get blocked when a lot of water vapor passes up the vent line (e.g.,steamy showers). In both situations, the blockage is transient and will likelydissipate when the weather warms up or when the ice melts in the hot sun.

Older buildings may have asbestos-containing transite plumbing vents.What is the problem with this? The transite can delaminate and, with time,clog the vent. Once again, sewer gases will backup due to blockage.

Plumbing Fixtures and Associated Traps

Associated with all plumbing fixtures, a “p” trap must be installed to pre-vent gases from backing up by retaining water in the angle to prevent gasesfrom returning. This is the case, as well, with the condensate water from anair conditioning unit, particularly wherein the water drains into the septic/sewer system. Sometimes there is either not enough space or the plumberchooses to install an “s” trap or even a jerry-rigged car radiator hose (not tocode). These are poor at retaining water and poor seals to prevent sewagegases from returning. If there is an “s” trap or some other strange fitting, besuspicious. See Figure 17.1.

One of the most common problems encountered in indoor air qualitycomplaints and sewer gases is a failed “p” trap. When the water in the trapevaporates and dries up, the gases return. This occurs mostly when a fixture(e.g., toilet or shower) is not used on a daily basis such as guest bathrooms,vacated homes, and unused shower stalls.

There have been reports of leaky, defective “p” traps, another source ofescaping sewer gases. A sign of leaks under a sink is the all too often foundwater staining and mold growth—adding more full to the medley of odors.

Signs of leaks around a toilet base are staining or the “wobble effect.”Staining is usually associated with a break in the wax ring seal. The wobbleeffect is usually associated with leaks into the floor or ceiling below the toi-let. It is referred to, herein, as the wobble effect, because the toilet moveswhen lightly pushed.

In-Foundation Line Breaks

On occasion, there may be a break in the sewer line in the concrete founda-tion. If carpet is resting on top of the concrete foundation, the carpet may be


unjustly implicated. To determine if there is an in-foundation leak, an inves-tigator may use thermal imaging if the concrete is accessible (see Figure 17.2),or a plumber can deploy a stealth camera to inspect the sewage lines fromwithin for cracks and leaks.

Septic/Sewage Drains and Lines

Besides the trademark sewer gas odors, signs of septic field failure involvewet, soggy areas where the sewage effluent has risen to the surface. Aplumber can track failures in the septic fields by flushing a dye into the sys-tem. But generally the occupant will have addressed this concern prior to theenvironmental consultant’s visit. The source of the odor is readily obvious.

Although not required by code, some plumbers place a sewer line ventat the foundation, immediately outside the building. There are always clea-nouts associated with a septic tank. All known or suspect potential cleanoutsshould be inspected.


Where hydrogen sulfide alone is encountered (without the presence of meth-ane) the source may not be sewer gasses. It may be tainted Chinese drywallor there may be another unidentified source of hydrogen sulfide gas. Forexample, another source may be decaying organic matter in a compost pile.

FIGURE 17.1Commercial office space—under sink sewer line with no “p” trap and jerry-rigged plumbing.


Wherein methane alone is encountered (without the presence of hydrogensulfide) and there is an associated odor, the source may be natural gas. Theodor may be a mercaptan, not hydrogen sulfide. If there is a natural gas linein or around the occupancy, a natural gas leak should be suspect and theoccupants vacated until the natural gas supplier can be contacted. This couldpotentially pose a very dangerous explosive situation and should be actedup immediately.

Confirmation of hydrogen sulfide and methane is significant to concludethe culprit is sewer gas. A leak somewhere in the sewage system is suspect.Tracking the source of the noxious sewer gases, using a real time monitor(e.g., MultiRAE), and an awareness as to the potential sources of leaks justmay lead to the end of the rainbow—at least isolate the general area fromwhence it came. It is highly unlikely that the investigator will get any realtime readings until he/she is next to or on top of the source. For example,sticking the monitor intake into a drain that has a failed or defective “p” trapwill give a reading. Five feet away, there may be no readings at all!

Summary

Not all findings are the end-all, be-all to confirm or deny the presence ofsewer gases. All too often consultants have overlooked the possibilities dueto failed associations to toilet facilities (e.g., gas leaks in sewer vents in wall

FIGURE 17.2Evidence of in-foundation sewer line leak—digital camera picture of area (left) and thermalimage camera picture (right).


cavities) or misdirection by the occupant (e.g., occupant associates noxiousodors with new furniture).

An awareness of the medley of discrepancies that may develop withinsewage systems can bring that which would otherwise be a dead end backfull circle to a possibility that would have been overlooked otherwise.Confirmation of the worst case noxious air may be accomplished by evacu-ated canister or ambient air bag and laboratory analysis for hydrogen sulfideand methane. Laboratory procedures and capabilities vary. Therefore, thelaboratory of choice should be consulted prior to sampling.

Sources may be tracked using field monitoring equipment with limiteddetection limits. Detection limits are key to all proper sewer gas evaluations!

305

18TaintedChineseDrywall

In January 2009, Chinese drywall became suspect of causing unpleas-ant odors and possibly electrical problems in Florida homes. Residentswere complaining of health problems and declared their homes unliv-able. Builders were accused of shoddy construction. Homeowners wereon the warpath claiming foul play. The Florida Department of Healthstated that “the levels of emissions from the drywall pose no immediatehealth threat.” Environmental consultants also stated that there were “nohealth threats.”

A huge uprising ensued. Insurance companies refused to pay on damages.Lawsuits were filed. Many builders picked up shop and disappeared into thedark of night. Lennar, the nation’s second largest home builder, respondedto the rising crescendo of unrest by replacing suspect drywall in some of thehomes, and still they were challenged.

In the meantime, in March, another battleground was forthcoming inLouisiana. There were complaints, once again, of the drywall emitting a rottenegg smell, causing respiratory problems, and corroding electrical equipment.A couple in a suburb of New Orleans filed a lawsuit, this time against drywallmanufacturers. Knauf Plasterboard Co. Ltd. of China, a German-owned, dry-wall manufacturer, was identified as the biggest supplier of Chinese drywallsent to the United States shortly after Hurricane Katrina in 2006.

By now, there had been 21 states throughout the United States and parts ofCanada that have made similar health and building claims associated withthe Chinese drywall. Most were in Florida, Louisiana, southeastern states,and coastal Virginia.

By April 2009, The Associated Press indicated that “imports of potentiallytainted Chinese building materials exceeded 500 million pounds during afour-year period of soaring home prices. The drywall may have been usedin more than 100,000 homes (built or) rebuilt after Hurricane Katrina inAugust 2005.” Some speculate the problem may go back as far as 2001, butthe purchase and installation of Chinese drywall on a massively large scaledid not occur until the devastation that was wrought by the 2004 hurricanein Florida.

As of October 2009, the Consumer Products Safety Commission had“received about 1,501 reports from residents in twenty-seven states, the


District of Columbia, and Puerto Rico who believe their health problems orcorrosion of metal components in their homes are related to Chinese dry-wall. Many homes with Chinese drywall are unlivable, and some home-owners allege to have been driven to the point of bankruptcy.” As a result ofthe drywall crisis, a group of U.S. senators called on the Federal EmergencyManagement Agency (FEMA) to help homeowners, seeking rental assistancefor people who have had to leave their homes because of Chinese drywall.

As of March 2010, there had been no ban or recall on any Chinese drywall,and Florida sought an emergency declaration for help with tainted Chinese dry-wall to allow homeowners and renters who have sustained uninsured losses toreceive financial assistance from FEMA and to receive stimulus grants from theObama administration to help repair homes that have Chinese drywall.

There is also an omnibus class action lawsuit filed by Parker, Waichman,and Alonso LLP, against Knauf Plasterboard Tianjin Co. Ltd. awaiting trial.Others named include, but are not limited to, Knauf’s parent company,distributor(s), and importer(s). Lennar Homes has also filed suit, claiming it“stands alongside its homeowners as a victim.”

With that said, homeowners appear to be the only parties filing com-plaints. Facility managers are either not affected or they are ignoring com-plaints lodged by building occupants. With the passage of time, the woes ofthe homeowner may also be shared with facility managers.

Health Effects

An indoor air quality investigation may be sparked by any of a number ofconcerns. There may be building-related health complaints and associatedodors. The building occupant(s) may have an expressed fear that they are

TABLE 18.1

States within the United States Confirmeda to Have Defective Drywall

Alabama Louisiana Ohioa

Arizona Maryland South CarolinaCaliforniaa Michigan TennesseeColorado Mississippi TexasDistrict of Columbiaa Nevada VirginiaFlorida New Jersey Washingtona

Georgia New Mexico Wisconsina

Georgiaa New York Wyominga

Kentucky North Carolina

a Reported only, not confirmed.Note: Puerto Rico and Canada also have confirmed reports of defective drywall.

TaintedChineseDrywall 307

victims of the “lethal” Chinese drywall gases, or they may have confirmedcorrosion or damage to their copper building materials. But in most cases,building occupants experience health concerns.

The most common building-related health complaints associated withtainted Chinese drywall are respiratory problems and eye irritation.Respiratory problems could be coughing, sneezing, difficulty breathing,bronchitis, and asthma. Many complain of nose bleeds and headaches, andsome complain of nausea, fatigue, sore throat, and runny nose—typicalallergy symptoms. Symptoms alone are not diagnostic!

Building occupants exposed to off-gassing from Chinese drywall are mostlikely to complain of a rotten egg smell, and some have reported an odor remi-niscent of burnt fireworks. Odor alone is not diagnostic! Yet in consort withsymptoms, the case strengthens. But there have been cases of no reported odorsin buildings where tainted drywall was encountered. Beware! Do not rush tojudgment if there is no associated odor. See Table 18.2.

TABLE 18.2

Summary of Interim Guidance—Identification of Homes with Corrosion fromProblem Drywall a

Threshold Inspection

Prerequisite positive response to both criteria for further consideration:1. Blackening of copper electrical wiring or air conditioning evaporator coils.2. The installation of new drywall (e.g., new construction or renovations) between 2001 and 2008.

Corroborating Evidence

If installed between 2005 and 2008, a home with characteristic metal corrosion problemsMUST also have at least two (2) of these corroborating conditions.

If installed between 2001 and 2004, at least four (4) of the following conditions must be met.1. Corrosive conditions in the home, demonstrated by the formation of copper sulfide on

copper coupons (e.g., test trips of metal) placed in the home for a period of 2 weeks to 30days or confirmation of the presence of sulfur in the blackening of the ground wires or airconditioning coils.

2. Confirmed markings of Chinese origin for drywall in the home.3. Strontium levels in samples of drywall core found in the home (i.e., excluding the exterior

paper surfaces) exceeding 1200 parts per million (ppm).4. Elemental sulfur levels in samples of drywall core found in the home exceeding 10 ppm.5. Elevated levels of hydrogen sulfide, carbonyl sulfide, or carbon disulfide emitted from

samples of drywall from the home when placed in test chambers using ASTM StandardTest Method D5504-08 or similar chamber or headspace testing.b

6. Corrosion of copper metal to form copper sulfide when copper is placed in test chamberswith drywall samples taken from the home.

a Federal Interagency Task Force on Problem Drywall: Interim Guidance (January 28, 2010) is a staffdocument and has not been reviewed or approved, and may not necessarily reflect the viewsof the Consumer Product Safety Commission or the Department of Housing and UrbanDevelopment.

b ASTM D5504-08: Standard Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence (2008).


Screening Considerations

Many building occupants have been subject to media hype regarding Chinesedrywall. If they are experiencing any of the symptoms and have had recentdrywall installed in their home or office building, they are likely to seekassistance. The health complaints may or may not be related to drywall, andthe fear generated by the media may encourage the homeowner or facilitymanager to be safe rather than sorry.

As there is considerable expense involved in having a structure assessed,some simple preliminary screening procedures have been offered by statehealth departments, the Consumer Product Safety Commission, Housing andUrban Development (HUD), and the U.S. Environmental Protection Agency(EPA). The laundry list of federal, state, and local contributors is long, andattorneys have varying opinions. But, in the overview, all basic homeownerscreening procedures are similar.

Homeowner Assessment

The Florida Department of Health developed a simple, online self-assess-ment guide that it recommended homeowners follow prior to a professionalinvestigation. See Table 18.3. If the homeowner answers “yes” to all the ques-tions, he or she should seek the assistance of an experienced professional.

Inspection Screening

First, the experienced professional should attempt to confirm or deny the pres-ence of Chinese sheet rock. This may be easier said than done! Although mostdrywall is stamped with the manufacturer’s name (e.g., Knauf) or country (e.g.,“Made in China”), the markings cannot be observed under painted surfaces.However, in a finished-out residence, markings may be observed from the attic(e.g., ceiling drywall), in the return air plenum, or any other place or means (e.g.,

TABLE 18.3

Step-by-Step Self-Assessment Guide for Home Owners1, 2

1. Was the house built after 2001?2. Is there blackening of the air conditioning evaporator coils or repeated A/C evaporator

coil failure?a

3. Did you observe blackening or corrosion any of the following?• Copper wires and electrical connectors• Uninsulated and uncoated copper pipes and fittings• Chrome-plated bathroom fixtures• Silver and copper jewelry• Mirror backing in bathrooms

a Coil failures indicative of this problem typically occur every 6 to 14 months.


borescope in drilled hole) where the backside of the drywall may be observed.Then, to add insult to injury, there may be more than one manufacturer orsource. Beware a rush to judgment. A negative finding does not close the case!

Second, the professional should look for corrosion. Tainted Chinese dry-wall gives off corrosive gases that are trapped in wall cavities. The gasescorrode copper, silver, and chrome-plated metals, turning them black.Unknown, unidentified corrosive gases build up inside the wall cavity, dam-aging exposed copper electrical wires and plumbing pipes not in the cavity,but the gases leak out around wall penetrations and are pulled into the airhandler through the return air plenum.

Corroded electrical wires and cooling coils are likely to fail or be incon-sistent. They should be placed at the top of the list of material and sites toinspect. Check for black corrosion on the following:

• Copper plumbing under sinks, particularly around the wall• Copper plumbing attachments behind dishwasher(s)/clothes washer

appliance(s), and water fountains• Electric leads behind light switches and wall plugs• Wall-mounted mirrors and decorative copper wall hangings• Cooling coils inside air handling units

The HVAC return air passes though an air plenum that is generally enclosed,surrounded by drywall. Wherein the drywall is tainted, the corrosive gasemissions will be drawn into the air handler and pass through the coppercooling coils. When this happens, the copper components start to corrodeand turn black. The conditioning unit slowly loses its efficiency and may failwithin 6 to 14 months. At this time, the drywall in the air plenum should besuspicious.

Corrosion to exposed, uninsulated copper plumbing may leak and electri-cal wiring may fail. So drywall associated with plumbing leaks and electri-cal shorts/failures should be areas most likely to be associated with taintedChinese drywall.

Components of Chinese Drywall

Currently, isolation of unique components in Chinese drywall as comparedto U.S. drywall is a work in progress. Yet all researchers agree on one thing.The elemental components of Chinese drywall are different from that ofU.S. drywall.

The EPA performed a limited study comparing drywall made in China tothat of domestic manufactured drywall. See Table 18.4.


According to EMSL analytical, there is considerably more iron disulfideand strontium sulfide in Chinese drywall than there is in U.S. drywall. It isalso alleged that the Chinese drywall has by-products from gas desulfuriza-tion plants—which adds even more sulfur to the mix.

The actual odorous gas(es) that cause(s) health effects and metal corrosionremain speculative. They have yet to be confirmed! Yet the evidence seems topoint to hydrogen sulfide and other sulfur-containing components.

Hydrogen sulfide has a rotten egg odor, and it is also a by-product ofbreakdown of iron disulfide and strontium sulfide—components of taintedChinese drywall.

FeS H S other sulf2highhumidity/moisture

2→ + uur-containing gases

SrS highhumidity/moisture→ +H S other sulfur-containing gases2

Strontium sulfide is used in fireworks. Could this possibly be related to theburnt fireworks odor?

The rotten egg odor is the most common complaint, but other odor com-plaints have been voiced as well. But all odor complaints seem to come fullcircle to sulfur-containing gases. See Table 18.5.

TABLE 18.4

Findings in U.S. EPA Study

ElementMade in Chinaa

(ppm)U.S. Manufacturedb

(ppm)

Strontium (Sr) 2,570 & 2,670 244 to 1,130Iron (Fe) 1,390 & 1,630 841 to 3,210

Note: ppm = mg/kg.a Two samples analyzed.b Four samples analyzed.

TABLE 18.5

Sulfur-Containing Gases

Gas

NIOSH REL-TWA

(ppm)LD50

(mg/kg)rat Odor

Odor Threshold3

(ppm)

hydrogen sulfide 10 rotten eggs 0.0045carbonyl sulfide N/A 23 burnt fireworks 0.055

sharp, irritating odor,sulfur dioxide 2C metallic taste 2.7carbon disulfide 1 medicinal –

0.00073–mercaptans 0.5C skunk 0.0000028

Note: C = ceiling exposure limit; 15-minute exposure.


The EPA claims the level of odor awareness for hydrogen sulfide is0.01 ppm, and they recommend an 8-hour acute exposure guideline level(AEGL) of 0.33 ppm. These are guidelines only, and the EPA does not offera guideline for homeowner occupancy and 24-hour exposures to hydro-gen sulfide.

Some researchers have noted that not all Chinese drywall off-gasses sul-fur-containing gases or causes corrosion, and not all corrosion is causedby tainted Chinese drywall. Corrosion may be caused by sewer gases, wellwater, and outdoor air contaminants (e.g., sour oil wells). On the other hand,not all structures that have tainted drywall exhibit signs of corrosion. Theproof is in the analysis!


Controversy reigns in the arena of the sampling and analytical methodolo-gies. No two laboratories agree on a common approach. Yet, they do agree onthe basic principals and objective.

The objective is to determine: (1) if the suspect drywall is Chinese manu-factured; (2) if it is off-gassing sulfur-containing gases; and (3) if it can causecorrosion. The objective may be accomplished by two or three of the meth-ods herein.

Bulk Sample Collection and Analysis for Identification of Chinese Drywall

Although the sampling and analytical methods are a work in progress, all lab-oratory researchers agree on one thing—the mineral components in Chinesedrywall are different from that of U.S. drywall. The story ends here!

Sample Collection

Bulk samples are collected to confirm that suspect drywall is indeed “Chinesedrywall.” This may not be necessary wherein the Chinese-made drywall hasalready been confirmed either by a visual inspection of the actual drywall orrecords requested by legal council.

Identify worst case scenarios (e.g., around areas where corrosion hasbeen confirmed or areas that emanate the greatest odor). Cut (e.g., using adrywall saw or drill-attached plug cutter) out a piece of the suspect dry-wall. The minimum cut-out bulk sample is a 2-inch diameter square (or2-inch plug). However, wherein the investigator requires multiple sam-ples of the same drywall for different analyses (e.g., headspace air sam-pling), a 1 foot square is suggested—unless indicated otherwise by the


laboratory. In light of the dickering about methodologies, the inspectorshould seek directions from the preferred laboratory. Put the sample(s)in a zip-lock bag, seal, label, and send to the laboratory with instructionsfor analysis.

Sample Analysis

Analyses are highly variable. The most frequently encountered methods areFourier transform infrared spectroscopy and x-ray fluorescence.

Fourier Transform Infrared Spectroscopy

The Fourier transform infrared spectroscopy (FTIS) is a powerful tool foridentifying types of chemical bonds in a molecule by producing an infraredabsorption spectrum that serves as a molecular “fingerprint.” For drywall, itcan be used to quantitate components of an unknown and compare them tothat of a known mixture. See Figure 18.1.

Although FTIR has been used extensively in litigation, some say the methodis severely lacking, not providing an unimpeachable resource of informationand not identifying the actual source or cause of the health and corrosionproblems. The minimum drywall sample should be 4 inches by 4 inches.

Xray Fluorescence4, 5

X-ray fluorescence, on the other hand, quantitates elemental components inweight percent (wt%). See Table 18.6. Strontium and iron appear at a consis-tently higher level in drywall made in China as compared to that of the U.S.The amount of drywall used is preweighed, and the wt% of strontium, iron,

FT-IR Comparison of Contaminated and Uncontaminated Drywall

3650 3150

Uncontaminated Contaminated Chinese

2650 2150Wavenumber (cm–1)

1650 1150 650

FIGURE 18.1Sample Fourier Transform Infrared Spectroscopy. Courtesy of assured Bio, Oak Ridge, Tennessee.


and other elements in the sample is reported either in terms of wt%, partsof sample per million parts of drywall (ppm), or milligrams of sample perkilogram of drywall (mg/kg). The latter are essentially the same (e.g., ppm =mg/kg).

If limited material is available for analysis, dust samples and scrapings maybe microanalyzed by scanning electron microscopy/elemental dispersivex-ray (SEM/EDX). The x-ray fluorescence approach appears to be the directiontaken by the EPA to differentiate drywall made in China verses the U.S.

Suspect Air and Headspace Sampling for Off-Gassing Components

Allegedly, not all Chinese drywall is tainted. Apparently, the laboratoriesare unable to get all confirmed Chinese drywall to off-gas hydrogen sulfideor other corrosive gases. So sulfide gases are the first step to confirming ordenying that suspect drywall is tainted.

Initially, investigators attempted grab air sampling in the occupied spac-es—using colorimetric detector tubes. Many investigators used the detectortubes for hydrogen sulfide gas that has a detection limit of 0.2 ppm, whichis above the odor threshold (e.g., 0.0045 ppm). Some attempted to use directreading instrumentation (e.g., photoionization detector confined space entrymonitor). Detection was no better!

So there has been a concerted effort to attain greater sample collection effi-cacy and higher analytical detection limits. Yet at the extreme low-level analyti-cal detection limits desired, improperly collected samples can be misleading.

Sample Collection

One approach to onsite air sampling may be performed sampling the airfrom within a wall cavity. The inspector should speculate as to the worstcase scenario, worst case wall cavity. Punch or create a hole large enoughto stick a “glass extension tube” or stop cock of a preconditioned evacuatedcanister or ambient air sampling bag (e.g., Tedlar® bag) into the wall cavityand collect a wall cavity air sample. The ambient air sample bag should bepreflushed onsite with the same air that is to be tested. After collecting theair sample, close the stop cock or valve, label, and send to the laboratory foranalysis by GC/MS or GC/SCD.

TABLE 18.6

X-Ray Fluorescence Elemental and ChemicalInvestigation

building materials ceramicsmetals (e.g., Sr, Fe) archaeologyforensic science glassgeochemistry


A more recent approach to on-site air sampling that will permit air sam-pling within the occupied space is the use of a Test America custom-madepassive monitoring canister. The monitor is to be placed in an open areawhere it collects hydrogen sulfide gases over an extended period of time—upto one week. After the collection is completed, the container can be sealed,labeled, and sent to the laboratory for analysis by GC/SCD.

A bulk sample is the simplest, most reliable approach—if the sample sitehas been chosen well! Take a minimum 6-inch by 6-inch bulk sample of sus-pect drywall. Put it in a zip lock bag seal, label, and send to the laboratorywith instructions for headspace analysis by gas chromatography/mass spec-trometry (GC/MS) or GC/sulfur chemoluminescence detector (SCD).

In all instances, an unexposed control should accompany each set of sam-ples—both inside and outside the laboratory. Cross-contamination by pre-existing ambient sulfides could find the lab or investigator in a quagmire asto how best to interpret unimpeachable results. Although not requested orrequired by most laboratories evaluating Chinese drywall, a blank can mini-mize speculation as to the samples efficacy.

Sample Analyses

Laboratory instrumentation gets greater detection limits than field colorimet-ric tests. The approach is still evolving as laboratories gain greater expertise.

Gas Chromatography/Mass Spectrometry (GC/MS)

Initially, GC/MS analysis of gas/chemical compounds with an emphasis onsulfide gases was the analytical method of choice—samples having been col-lected onsite or in the laboratory as bulk sample/headspace air samples. Thesulfide detection level is 20 ppb. This was considered a great improvementover the detector tubes, but still, the odor threshold of hydrogen sulfide (e.g.,4.5 ppb) is lower that the GC/MS is capable of detecting.

Gas Chromatograpy/Sulfur Chemoluminescence Detector (GC/SCD)

Gas chromatography/sulfur chemoluminescence detector is a methodsimilar to GC/MS. Only instead of the GC/MS characterization and iden-tification of gas/chemical compounds using an extensive computer libraryof gas-chemical characterization and identification, the GC/SCD looks atsulfur-containing compounds only—using standards for identification. TheGC/SCD detection limit for sulfur-compounds is 5 ppb, more powerful thanthat of GC/MS, and GC/SCD is less expensive.

In the laboratory, ALS Laboratory Groups has compared results of thesame lot of drywall both with high humidity and without. The findingswere a surprise! Hydrogen sulfide levels have been 10 percent less whenpresented with high humidity than with low humidity. This appears to becontrary to the consensus that off-gassing of corrosive gases occurs mostalways in high humidity environments.


Corrosion Testing

All laboratories go for the corrosion test. After all, corrosion testing is thecoup de grace, the nail in the coffin, for identifying tainted Chinese drywall.The goal is confirmation that onsite observed copper corrosion was causedby suspect drywall from the vicinity of the blackened copper. The approachvaries between laboratories, but the basic premise is the same.

Sample Collection

Bulk samples are analyzed by a laboratory. The collection approach shouldbe similar to that described under the section on “Bulk Sample Collection forIdentification of Chinese Drywall—Sample Collection.”

Copper Pipe 7 to 14Day Incubation

At EMSL, a copper pipe is installed within a 2-inch by 2-inch sample of dry-wall and placed in a glass jar at a temperature of 99 to 100°F and 90 per-cent relative humidity. The condition of the copper is monitored over a 7- to14-day time period. After 2 weeks, the extent of corrosion is observed wherethe copper pipe was touching the drywall and around the penetration point.This method does not provide the cause of the corrosion, but does confirm

FIGURE 18.2Corrosion testing in temperature controlled incubator (top) and results (bottom). (Courtesy ofEMSL Analytical, Cinnaminson, New Jersey).


that it is tainted. Then, EMSL goes one step further and performs an SEM/EDX microanalysis of scrapings from the corroded copper to determine if itis sulfur-related.

Another, more “aggressive” approach involves:

• Remove the paper from the drywall sample—front and back• Sand the surface of the exposed drywall—allegedly to “activate”• Direct contact flat copper to the activated surface of the drywall• Enclose and maintain contact for up to 14 days• Check for corrosion

As some people suspect poorly processed Chinese paper as being a likelysource of sulfide gases, the aggressive approach eliminates that possibility.

There is no standardized procedure for corrosion testing. There seems tobe as many different approached to corrosion testing as there are laborato-ries that perform the services. See Figure 18.3.

Copper Wire 48Hour Incubation

At ALS Laboratory Groups, a stripped copper wire is installed in a glassjar along with a 2-inch by 2-inch sample of drywall and heated for 48hours. The lab does not increase the humidity when testing for corrosion.The condition of the wire is then evaluated for corrosion and tarnishingwithin 48 hours.

Microbiological Testing

Drywall in landfills produces sulfur gases—in particular hydrogen sulfide.Under anaerobic (lack of oxygen) conditions, moisture, and sulfur-reducing

FIGURE 18.3Corrosion Test of Copper Discs (environmental chamber with temperature, humidity, andpressure maintained throughout the test)— corrosion resulting from tainted drywall (left) ascompared to no corrosion (right). (Courtesy of Assured Bio, Oak Ridge, TN.)


bacteria, drywall (about 90 percent CaSO4 and 10 percent paper) produceshydrogen sulfide. An attempt to duplicate this process in laboratories hasmet with poor results, and the chemistry is nonspecific. This test procedureis an option that appears to provide—no useful results.


The investigation’s objectives are to confirm the presence of tainted Chinesedrywall. Sampling and analysis are threefold. Laboratory analyses can con-firm suspect drywall to have been made in China, to be off-gassing sulfur-containing gases, and to cause copper corrosion.

Chinese Manufactured Drywall

Literature abounds with information regarding components of Chinese dry-wall as compared to that which was manufactured in the U.S. Yet there isconsistency regarding the element of strontium. Whereas the domestic lev-els of strontium range from 244 to 1130 milligrams per kilogram (mg/kg),Chinese drywall has levels greater than 2570 and sometimes as high as 5000mg/kg.6, 7 And high levels of strontium appear (not conclusively confirmed)to be associated with copper corrosion. So high levels of strontium are astrong indicator that the sample is Chinese drywall.

Fingerprint comparison by FTIS has been used in litigation, but the tech-nique is coming into question. The purpose is simply to compare and is nota stand-alone approach to confirming or denying the presence of Chinesemade drywall. Once again, not all Chinese drywall off-gases noxious odorsthat causes health problems or corrosion.

If selected from the vicinity of known corrosion, a sample is more likelyto represent a worst-case scenario whereby a negative finding is signifi-cant in determining that Chinese drywall is not present. Positive findingsare significant.

On the other hand, a negative finding of a random sample (such as onetaken for a convenient site on a wall) that is not associated with corrosionmay indicate nothing more than that specific sample may not be tainted. So,the plot thickens!

Off-Gassing Sulfur-Containing Gases

Not all Chinese drywall is tainted, resulting in off-gassing of sulfur-con-taining gases and causing corrosion. By the same token, not all tainteddrywall results in off-gassing within every wall cavity. Was the complaintlodged prior to the time required for corrosion to develop (e.g., immediately


after installation)? If a year has passed since drywall installation and therehas been no observed corrosion, were the conditions such that the drywallwould have off-gassed? Conditions not conducive to off-gassing are lowhumidity (e.g., a year of drought) and cooler temperatures (e.g., north centralU.S. climate). So the question remains, “Is the confirmed Chinese drywalltainted, able to cause corrosion?”

Air samples and corrosion testing are the end run. If corrosive hydrogensulfide gas is confirmed by colorimetric detector tube (poor detection), GC/MS (moderate detection), or GC/SCD, the drywall is tainted.

Whereas some laboratories diverge from hydrogen sulfide as the indi-cator gas, ALS laboratory groups has found that all drywall, Chinese anddomestic, will give off carbonyl sulfide and carbon disulfide. Sulfur dioxideand methyl/ethyl mercaptans were not present in any of the samples. OnlyChinese drywall gives off hydrogen sulfide!

ALS laboratory group has speculated that the source of the carbonylsulfide and carbon disulfide are paper. They have performed analyses ofpaper products both from drywall paper backing and cardboard. Both havebeen demonstrated to off-gas carbonyl sulfide and carbon disulfide. Thusalthough the mechanism is unknown, Chinese drywall exclusively gives offcorrosive hydrogen sulfide. This approach alone may circumvent and singu-larly prove that the drywall is Chinese made—cut down on the number ofsamples and on the analytical cost(s).

Causes Corrosion

If copper corrosion or tarnishing is demonstrated, the drywall is likelytainted. Confirmation of sulfur in the corrosion by means of SEM/EDXmicroanalysis is a more powerful case leading to tainted Chinese drywall.

Summary

The 2009 Florida debacle with tainted Chinese drywall was the begin-ning of a maelstrom of litigation that has spread nationwide and impactedthousands of homes. Early on, environmental consultants and the FloridaDepartment of Health had been sent on a witch hunt to find the culprit thatwas the source of sulfurlike noxious odors, health complaints, and corrosionof copper building materials.

As Chinese drywall appeared to be the bane of all the complaints, therewas a rush to develop a means to evaluate the suspect drywall. As there wasno established methodology, diverse sampling and analytical proceduresevolved. The source was known, but the actual component that causes theproblems remained, and still remains, unknown. Many will speculate, but as


no one has conclusive evidence, sampling and analytical methods can onlyfocus on findings that seem to be consistent with problem residences.

Homeowner self-assessment screening guides generally consisted in aid-ing those in suspect residences. Investigators, too, have developed a presa-mple screening process. The components of Chinese drywall have foundcommon ground as compared to U.S. drywall. Sampling and analyticalmethodologies are consistently similar in intent and dissimilar in procedure.No one method is perfect, but they get the job done. In brief, once again, thefollowing questions must be answered:

1. Is the suspect drywall Chinese manufactured? Unless requestedby the client or lawyer, the experienced professional may skip thisquestion and go on to Item 2.

2. Is the suspect drywall off-gassing hydrogen sulfide?3. Is the suspect drywall causing corrosion?

References

1. Florida Department of Health. SelfAssessment Guide for Signs That a Home May Be Affected by Drywall. Retrieved from www.floridashealth.org/Environment/community/indoor-air/drywallFAQ.html (May 2009).

2. Florida Department of Health. Case Definition for Drywall Associated Corrosionin Residences. Retrieved from www.doh.state.fl.us/environment/community/indoor-air/casedefinition.html (December 18, 2009).

3. AIHA. Odor Thresholds for Chemicals with Established Occupational Health Standards.AIHA Press, Fairfax, Virginia (1997).

4. Spates, W.H., III et al. Evolution of Chinese Drywall Inspections and Findings Based on Laboratory Data, FDOH Guidelines and the Need to Incorporate New and Productive Inspection Techniques. Indoor Environmental Technologies, Inc., Clearwater,Florida (2009).

5. Rajiv, R.S. Chinese Drywall Testing Guidance for Residential and CommercialBuildings. Real Estate News, Tampa, Florida (February 15, 2009).

6. Spates, W.H., III et al. Evolution of Chinese Drywall Inspections and Findings Based on Laboratory Data, FDOH Guidelines and the Need to Incorporate New and Productive Inspection Techniques. Indoor Environmental Technologies, Inc., Clearwater,Florida (2009).

7. Rajiv, R.S. Chinese Drywall Testing Guidance for Residential and CommercialBuildings. Real Estate News, Tampa, Florida (February 15, 2009).

321

19GreenBuildings

It is alleged by the U.S. Green Building Council that green buildings canreduce energy consumption by 26 percent and that retrofitted existing build-ings may reduce energy usage as much as 30 to 40 percent.1 New York Cityand Washington, D.C. require all new construction be “green” certified. InDecember 2009, Mayor Michael Bloomberg of New York City attempted toimpose mandates that existing buildings go green and failed. Other munici-palities have also tested the firestorm of public opinion for mandating green.And there has been a lot of push back!

Opponents claim the cost for going green will increase construction costs10 to 20 percent. According to the Green Building Finance Consortium, aLeadership in Energy and Environmental Design (LEED) Platinum ratingwill result in higher initial costs of 11.5 percent for new construction.2 Theproponents of green suggest the construction costs will diminish withtime, and energy savings will offset the increased costs.

Retrofitting existing buildings requires even greater expense. For example,all single pane aluminum windows must be replaced by double pane vinylwindows which, irrespective of building size, can be extremely expensive,and window replacement is only the beginning.

The intent of going green is to create a more energy efficient, environ-mentally friendly indoor air environment. In the past, energy efficiency wassynonymous with a tight building. Tighter is better! Closing in and sealingup buildings in occupied, conditioned air spaces lead to trapped emissionsfrom building materials, furnishings, and other products. Tight buildingsresulted in “sick building syndrome.”

In the 21st century, “green” is being redefined. The champions of greennow seek to certify green buildings as those that have minimal impact on theenvironment and are healthy for building occupants. The playing field haschanged. Health and indoor air quality must work in consort with energyefficiency. This is where the environmental professional has a defined proac-tive role to play.


21st Century Green

In 1998, the U.S. Green Building Council developed technical criteria for cer-tifying green building construction. The program comes under the headingof LEED—a purely voluntary, market-driven approach to rating energy effi-cient, environmentally friendly building designs. It does not have the forceof law! The driving force is energy cost savings, increased resale value, andresource conservation.

Having originated in the United States, the LEED Certification Programis beginning to go global. State and local governments are adopting the pro-gram for public-owned and public-funded buildings, and there are initiativesin federal agencies. For example, the U.S. General Services Administrationmandates that all new projects and renovations on nonmilitary governmentconstruction must meet the minimum LEED standards.

Privatelyownedbuildingsandresidencesareengagedaswell.Homeownersare a hard sell in hard times, but some of the wealthier homeowners areengaged and motivated to incorporate green into their home designs. Onehomeowner with a Platinum Certification commented, “My wife and I arecommitted to going green and doing the right thing. In terms of the buildingdesign, saving resources, and setting an example for our colleagues and ourchildren.”

Privately owned buildings that currently are LEED certified include hotels(e.g., Proximity Hotel in North Carolina), small businesses (e.g., Office Depot inAustin, Texas), large businesses (e.g., L.L. Bean in Mansfield, Massachusetts),commercial buildings (e.g., One Boston Place in Boston, Massachusetts), andbanks (e.g., Banner Bank Building in Boise, Idaho). Libraries, schools, andretail stores have also been certified.

The LEED proposes a comprehensive strategy for optimizing indoor airquality and minimizing potential problems. This strategy had become the“gold standard” for ensuring good indoor air until the recent publicationof the American National Standards Institute/American Society of Heating,Refrigerating and Air Conditioning Engineers (ANSI/ASHRAE) Standard189.1.

In 2009, ANSI and ASHRAE proposed ANSI/ASHRAE Standard 189.1,“Standard for the Design of High-Performance, Green Buildings—ExceptLow-Rise Residential Buildings” (ASHRAE Standard). Its stated purposeis to “provide minimum requirements for the sitting, design, construction,and plan for operation of high performance green buildings … to balanceenvironmental responsibility, resource efficiency, occupant comfort andwell being, and community sensitivity.” In other words, the Standard issimilar to the LEED Certification Program with muscle—exclusive of low-rise residential buildings.

GreenBuildings 323

The Standard does not apply to single-family residential structures, multi-family structures (i.e., less than three stories high), manufactured homes, andbuildings without utilities. It is a standard, not a guide, and it does not afford arating system. The rating system remains a management tool of the LEED.

Both the LEED and ANSI/ASHRAE Standard 189.1 have a provision forbuilding flush-out* and for preoccupancy air monitoring. Hence, the envi-ronmental professional is called upon to confirm a healthy environment in“green buildings.”

Green Flush-Out Protocols

The LEED approach to assuring good indoor air quality is neither man-dated nor strongly suggested in all occupied buildings where certificationis desired. The ANSI/ASHRAE Standard 189.1 goes the extra mile and man-dates postconstruction activities and air monitoring in high performancebuildings only, and compliance may be required by the building owner(s).Both the LEED and the ASHRAE Standard are voluntary, best-practice direc-tives for healthy indoor air quality.

* Flush-out is a reference to the replacement of all indoor serviced air by the outdoor air. Theflush-out rate is the volume of outdoor air required to replace the same volume of indoor airfor each area serviced.

LEED Key Performance Areas for Residential3

(Points Possible/Minimum Points Required)

Sustainable Site Development (22/5)Water Savings (15/3)Energy Efficiency/Energy Star and Atmosphere (38/0)Materials, Resources, and Waste Management (16/2)Indoor Environmental Quality Management (21/6)Innovation and Design (11/0)Awareness and Education of Owner(s) (3/0)Location, Access, and Neighborhood Development (10/0)

Certification Thresholds• Certified: 45.0 points• Silver: 60.0 points• Gold: 75.0 points• Platinum: 90.0 points


LEED Indoor Air Quality Management Plan

Upon completion of construction, LEED recommends a building be flushedout. A building flush-out involves turning on the air handler with themakeup air fully opened. They suggest a postconstruction, preoccupancyflush-out of 14,000 CFM/ft2 while maintaining an internal temperature ofat least 60°F and no higher than 60 percent relative humidity. The processmay take as much as two weeks or more depending upon the capacity ofthe air handler(s).

An alternative flush-out* schedule may be invoked if time is an issue. Apostconstruction flush-out of 3,500 CFM/ft2 as allowed prior to occupancy,but the full 14,000 CFM/ft2 flush-out must be completed in order to obtaincertification points. Yet delayed occupancy or costs for conditioning the airin early occupancy can have negative consequences. The alternative to acomplete flush-out is air testing.

The required flush-out may be reduced or eliminated entirely whereinair sampling is performed, and measured parameters are below LEED pre-scribed limits. The parameters are formaldehyde, total volatile organic com-pounds (VOC), carbon monoxide, and 4-PCH.

ANSI/ASHRAE Standard 189.1—Construction and Plans for Operation

In accordance with ASHRAE 189.1, the HVAC system(s) shall remain cov-ered, clean, and nonoperational during construction. After constructionends, prior to occupancy and with all interior finishes installed, a postcon-struction, preoccupancy building flush-out or optional baseline air monitor-ing is performed.

The Standard mandates a building be flushed in accordance with mini-mum prescribed limits as defined by a formula:

TAC (total air changes) = V × 1/A × 1/H × 60 min/h × 24 h/day × 14 days

V = outdoor air intake flow (CFM)

A = floor area (ft2)

H = ceiling height (ft)

The flush-out shall be continuous and the supplied outdoor air rate shall beno less than the design minimum, unless occupancy is desired prior to com-pletion of the flush-out. Wherein occupancy is desired prior to completion ofthe time required for minimal air exchanges, the space(s) may be occupiedafter half the minimum has been met and after air sampling compliance.

* Flush-out is a reference to the replacement of all indoor serviced air by the outdoor air. Theflush-out rate is the volume of outdoor air required to replace the same volume of indoor airfor each area serviced.

GreenBuildings 325

Baseline air sampling must not be conducted prior to 24 hours after thedesigned outdoor air flow rate has been established—for each HVAC servicearea. One set of breathing zone samples should be performed for each HVACservice area. More sample sets are required should an HVAC service areaexceed 25,000 ft2 or greater than one contiguous floor area.

If a sample set exceeds the maximum concentration limits, additionalflush-out with outside air is required and a retest performed afterwards forthe specific parameter(s) exceeded in the initial testing. Repeat the processuntil all requirements have been met. Retests should be performed at thesame locations as previous test sets.

Biannual monitoring is required thereafter by at a minimum of one ofthe following:

1. Air monitoring at previously prescribed sites.2. Monitoring occupant perceptions of indoor air quality by any

method, including, but not limited, to occupant questionnaires.3. Occupant complaint/response program for indoor air quality

complaints.

Annual air testing of all sites is recommended minimally for those contami-nants that tested marginal on the postconstruction sampling.

Each sample set consists of formaldehyde, carbon monoxide, 4-PCH, spe-cific identified volatile organic compounds, particulates, and ozone. If thereis no carpeting in the building, 4-PCH may not be required. 4-PCH has beenassociated only with rubber backed, wall-to-wall carpeting.


The LEED program does not ascribe to strict air monitoring procedures, andthe LEED parameters are similar to, but less restrictive than, the ASHRAEStandard parameters. Both programs define limits for formaldehyde, totalVOCs, 4-PCH, particulates (PM 10), and carbon monoxide. The ASHRAEStandard further requires identification of up to 29 additional organic com-pounds (formaldehyde and 4-PCH are included in the list) and PM 2.5 (alongwith PM 10). The sampling methods for each contaminant group (i.e., par-ticulates, carbon monoxide, formaldehyde, 4-PCH, and VOCs) are different.

Particulate sampling may be accomplished by direct reading, data loggingparticle counter with mass display and by sample collection. See Figure 19.1. ForLEED, the particle counter must be capable of measuring all particle sizes lessthan 10 microns (PM 10) to a total mass below 50 microns/m3 (µg/m3). For theASHRAE Standard, it must measure particle size less than 2.5 microns (PM 2.5)as well as 10 microns to total mass below 35 microns/m3, and monitoring must be


performed for 24 hours. There are no time requirements for LEED. Forewarned,the particle counter does not rely on actual measured weight but on projectionsand calculations (e.g., average weight per particle size).

LEED—PM 10 reading to below 50 µg/m3

ASHRAE Standard—PM 2.5 and PM 10 reading to below 35 µg/m3

On the other hand, sample collection is based on actual measured weight.Yet sample collection produces only one number—total weight/m3. The par-ticle counter has the benefit of multiple data points.

In simple terms, the particulate air samples are collected on a filter that islater weighed and results calculated by a laboratory on the basis of the sampleair volume reported by the environmental professional. Now, to attain PM 2.5or PM 10, a size-selective particle sampler is required. For example, a personalmodular impactor (PMI) and personal environmental monitor (PEM) havemachined holes that limit the particle size entry and impaction onto the filter.

FIGURE 19.1MetOne Aeroset 531 Particle Counter—mass monitor and particle counting (Courtesy ofMetOne, Grants Pass, Oregon.).

GreenBuildings 327

A different sampler is generally required for each particle limit (e.g., PM 10)and, in some cases, for desired flow rate. A different PEM sampler is requiredfor different flow rates (i.e., 2, 4, and 10 liters/minute). For the PMI, the flow rateis 3 liters/minute with no other choices available. The following is:

• Sampling equipment: air sampling pump, size-selective particlesampler (e.g., PM 10 and PM 2.5 PMI impactor). See Figures 19.2and 19.3.

• Bounce reduction: oiled-impaction disks (e.g., PMI) or oiled impac-tion ring (e.g., PEM).

• Collection medium: 37 mm PTFE filter or 37 mm Tissu Quartz filter.• Flow rate(s): variable, impactor dependent (i.e., SKC personal modu-

lar impactor—3 liters/minute).• Sample duration (based on flow rate of 3 liters/minute): minimum of

3.3 hours (LEED); 24 hours required (ASHRAE Standard).• Detection limit(s): 50 µg/m3 (3.3 hours); 7 µg/m3 (24 hours).• Analytical method: gravimetric.

FIGURE 19.2PMI for PM 10 (Courtesy of SKC, Eighty Four, PA.).


25-mm Impaction

Substrate

Filter Cassette Top

Filter Cassette Bottom

PM2.5 Inlet (Coarse Ring)

25-mm Filter in ImpactionSubstrate Position

Filter Cassette Top

37-mm Final Collection Filter

Support Screen

Filter Cassette Bottom

Exhaust

FIGURE 19.3Breakdown of a personal modular impactor—PMI course includes PM 10 and PM 2.5 in sameunit (Courtesy of SKC).

GreenBuildings 329

With the sample time and laboratory analytical turnaround time, sample col-lection is considerably more time-consuming than the particle counter, but it ismore reliable. A quick real time data reading that reads well within the limit(s)may be deemed acceptable, or a quick reading in excess of the limit could pro-vide rapid information upon which to act to correct the cause of the elevatedlevels, even prior to completion of the 24-hour monitoring time. Ideally, bothmethods would provide the best of all worlds. That is in a perfect world!

Whereas LEED does not clarify sampling methods, the ASHRAE Standarddefines sampling and analytical procedures for the organic compounds—formaldehyde, volatile organic compounds (VOC), and 4-PCH. The ASHRAE-defined testing procedures include one of or a combination of the following:(1) EPA TO-1 (similar to TO-17, collection with Tenax®, thermal desorption,analysis by GC-MS), (2) EPA TO-11 (aldehydes and ketones; similar to NIOSH2016), (3) EPA TO-17, and (4) ASTM Standard Method D5197 (aldehydes; simi-lar to NIOSH 2016).

EPA TO-17 is the most all inclusive approach for identification and anal-ysis of most volatile organic compounds including 4-PCH, acrylonitrile,2-ethylhexanoic acid, caprolactam, and phenol. The procedure, as detailed inChapter 8, “Volatile Organic Compounds,” is summarized as follows:

• Equipment: air-sampling pump• Capture media: thermal desorption tube (e.g., Carbopak™), which

generally requires laboratory cleaning, conditioning• Flow rate (TO-17): 10 to 50 milliliters/minute• Flow rate (laboratory experience/preference): 50 to 100 milliliters/

minute• Air volume limits: 1 to 6 liters (variable higher limits based on mul-

tibed sorbent and required reporting limits may be as high as 10liters)

• Sample duration: minimum of 4 hours• Desorption: thermal desorption• Field blanks: minimum of one for up to ten samples in any given

sampling period• Analysis: TD-GC-MS• Limit of detection: 25 ng/sample (varies by laboratory)• Special handling and shipping instructions: laboratory dependent

(some require ice pack for shipping)

Total VOCs, as required by LEED, is considerably less involved. LEED airsampling may be done by any of the methods as presented in the Chapter 8.Charcoal solid sorbent (active and passive) sample collection and analysis byGC-FID is the easiest, most commonly used method, yet charcoal is limited in


its ability to collect polar VOCs and less volatile VOCs. Only TO-1 and TO-17 areall inclusive, and 4-PCH and other carpet emission product are collected onlyby TO-1 and TO-17.

As in all things big and small, there is an exception to every rule.Formaldehyde requires separate sampling and analysis from that of VOC iden-tification. Yes, it is a volatile organic compound, but formaldehyde is not readilyanalyzed by gas chromatography. The rationale for this is that the referencestandard is generally formalin (formaldehyde in water), and water does not dowell in a gas chromatograph. As such, formalin reference standards tend tofluctuate and are not reliable in a GC/MS. Furthermore, multibed solid sorbents(EPA TO-17) tend not to capture the highly volatile organics such as formalde-hyde. EPA TO-1, NIOSH 2016, and ASTM Standard Method D5197 are ideal foranalyzing aldehydes. The NIOSH 2016 procedure is summarized as follows:

• Sampling equipment: air sampling pump• Collection medium: DNPH treated silica gel sorbent• Flow rate(s): 0.1 to 1.5 liters/minute• Sample duration: minimum of 4 hours• Field blanks: minimum of one for up to ten samples in any given

sampling period• Maximum air volume: 100 liters• Sample duration for indoor air quality: 8 hours• Detection limit: 50 ppt (1.2 liters/minute for 8 hours)• Analytical method: HPLC-UV detector

Carbon monoxide and ozone may be monitored by gas specific directreading instrumentation or by monitoring equipment designed to operatein combination with other gases. A four-gas confined space entry monitoralways has a carbon dioxide sensor. An ozone meter is generally a single unitand should be able to read levels as low as 0.075 ppm (e.g., EnvironmentalOzone Meter Model Z-1200 reads to 0.02 ppm).

LEED—Total VOCs 500 μg/m3ASHRAE Standard—Component VOCs 2.5-7,000 μg/m3

LEED—4-PCH 5 μg/m3ASHRAE Standard—4-PCH 2.5 μg/m3

LEED—Formaldehyde 50 ppbASHRAE Standard—Component VOCs 33 μg/m3 (~26 ppb)

GreenBuildings 331

Ozone air sampling may be performed. The Occupational Safety andHealth Administration (OSHA) ID-214 Method for ozone air sampling isas follows:

• Sampling equipment: air sampling pump• Collection medium: 2-impregnated glass fiber filters coated with

solution containing NaNO2, K2CO3, and glycerol in water• Flow rate: 0.25 to 0.5 liters/minute• Field blanks: minimum of one for up to ten samples in any given

sampling period• Maximum air volume: 90 liters• Sample time: 3 to 8 hours• Detection limit: 0.03 ppm (90-liter air sample)• Analytical method: IC

There are various direct reading, real-time indoor air quality instrumentsavailable that are capable of measuring and data logging many of the LEEDparameters. For instance, the Wolf Pack with PM-205 can read PM10, carbondioxide, and total VOCs. See Figure 19.4. It does not monitor formaldehyde levels,and 4-PCH must be collected by air sampling and analyzed by a laboratory.


Interpretation of results is simple! Either the building indoor air qualitypasses or it fails. Pass/fail is based on the maximum concentration limits asset forth by LEED (see Table 19.1) and the ASHRAE Standard (see Table 19.2).While the LEED remains the benchmark for residences, the ASHRAEStandard for high-performance buildings is considerably more restrictive.

In accordance with the ASHRAE Standard, each sampling point where themaximum concentration limits have been exceeded, an additional flush-outis mandated, and a retest for those specific parameter(s) that were exceededshall be done. Repeat this procedure until parameters have passed the litmustest. All repeat samples should be taken from the same locations as the first.

LEED—Carbon monoxide 9 ppmASHRAE Standard—Carbon monoxide 9 ppm (or 2 ppm above

outdoors)

ASHRAE Standard (only)—Ozone 0.075 ppm (8-hour sample)


FIGURE 19.4WolfPack with PM-205 particulate concentration meter (Courtesy of Graywolf SensingSolutions, Shelton, Connecticut).

TABLE 19.1

LEED’s Maximum Concentration of Air Pollutants

Maximum ConcentrationContaminant µg/m3 (unless otherwise indicated)Particulates (PM10) 50Carbon monoxide 9 ppm or no greater than

2 ppm above outdoor levelsTotal VOC 500Formaldehyde 50 ppb4-PCHa 6.5

a This test is only required if carpets and fabrics with styrene butadiene rubber(SBR) latex backing material are installed as part of the base building systems.

GreenBuildings 333

TABLE 19.2

ANSI/ASHRAE Standard 189.1 Maximum Concentration of Air Pollutants

ContaminantMaximum Concentration µg/m3

(Unless Otherwise Indicated)

Particulates (PM2.5) 35 (24 hours)Particulates (PM10) 35 (24 hours)Carbon Monoxide 9 ppm or no greater than 2 ppm

above outdoor levelsOzone 0.075 ppm (8 hours)

OrganicCompounds

Acetaldehyde 140Acrylonitrile 5Benzene 601,3-Butadiene 20t-Butyl methyl ether (Methyl-t-butyl ether) 8,000Carbon disulfide 800Caprolactama 100Carbon tetrachloride 40Chlorobenzene 1,000Chloroform 3001,4-Dchlorobenzene 800Dichloromethane (methylene chloride) 4001,4-Dioxane 3,000Ethylbenzene 2,000Ethylene glycol 400Formaldehyde 33 (~26 ppb)2-Ethylhexanoic acida 25n-Hexane 7,000Naphthalene 9Nonanala 13Octanala 7.24-Phenylcyclohexene (4-PCH)a 2.5Styrene 900Tetrachloroethene (Tetrachloroethlyene,Perchloroethylene)

35

Toluene 3001,1,1-Trichloroethane (Methyl chloroform 1,000Trichloroethene (Trichlorethylene) 600Xylene isomers 700Total volatile organic compounds – b

a This test is only required if carpets and fabrics with styrene butadiene rubber buildingsystems (SBR) latex backing material are installed as part of the base.

b TVOC reporting shall be in accordance with CA/DHS/EHLB/R-174, StandardPractice for the Testing of Volatile Emissions from Various Sources Using Small-ScaleEnvironmental Chambers, and shall be in conjunction with the individual VOCs listedabove.


Summary

Going “green” by LEED is based on points, a rating system for “all structures,”and indoor air quality testing is neither required nor is it the main focus.Although it has continued make headway in the public sector, the LEED hasseen limited success in the private sector. As there is only an award of onepoint for air quality testing, there is very little incentive for building ownersto seek the services of an environmental professional. Consequently, withouta building flush-out and confirmatory air monitoring, occupants of LEED-rated buildings may and have registered building-related health complaints.

Most residential HVAC systems do not have the ability to exchange outdoorfresh air for a postconstruction flush-out. Many homes do not have operablewindows that can be opened to allow for air exchange with the outdoors. Sohomeowners rarely have the ability to flush-out their home either mechani-cally or through dilution ventilation (e.g., opening all doors and windows),and if it were possible, there is no means to filter the outdoor dust and debris.

Subsequently, there have been reports of occupant dissatisfaction with thehigh cost of a LEED building and unexpected building-related health com-plaints. Litigation rears its ugly head, and the environmental professionalends up in an after-the-fact web of lawsuits. Could this not have been pre-vented with the optional postconstruction air quality testing?

On the other hand, the ASHRAE Standard is a recommended standard, and itis inclusive of and focused on indoor air quality. The standard “mandates indoorair quality testing” after a high-performance building has been flushed. As idealas it is at addressing indoor air quality in green buildings, the ASHRAE Standardexcludes most residences and multifamily structures up to three stories high. Thisis not to say homeowners cannot apply the standard wherein they so choose!

The exposure limits and parameters of the ASHRAE Standard far exceedthat of the LEED maximum concentrations. For example, PCH limits are 2.5and 6.5, respectively. There are considerably less restrictive limits for theLEED in all cases.

Furthermore, the ASHRAE Standard parameters include sampling forPM 2.5 particles, identification of specified organics (instead of total organ-ics), and ozone. “Green” has just taken on an all new meaning—healthy!

References

1. U.S. Green Building Council. USGBC and Sierra Club Volunteers Lead GreenBuilding Tours Across the U.S. (press release). March 16, 2010.

2. Beth Anderson. LEED Certification Program Leads to Potential Profits. NulineInvestor (Dec. 3, 2007). http://www.nuwireinvestor.com/articles/leed-program-leads-to-potential-profits-51367.aspx

3. LEED for Homes Checklist. U.S. Green Building Council (2010).

335

Glossary

abscess: A cavity containing pus and surrounded by inflamed tissue.acid fast: A method of bacterial identification. Acid fast bacteria retain a

fuschin stain where other bacteria are rapidly decolorized whentreated with a strong mineral acid.

adsorption: Process of collecting a liquid or gas onto the surface of a solid orliquid sorbent.

aerobic: Requiring the presence of oxygen for growth. Some aerobic microbesmay form capsules, or spores, when left in an oxygen-deficientenvironment.

aflatoxin: Mycotoxin created by the molds Aspergillus flavis and parasiticus, aknown cancer-causing substance.

algae: Plantlike organisms that practice photosynthesis (requiring light) and,for the most part, live in aquatic environments. They are occasion-ally implicated in outdoor allergies.

allergic pneumonia: An inflammation of the lungs resulting directly froman allergy, usually to some type of organic dust.

alveolitis: An allergic pulmonary reaction characterized by acute episodesof difficulty breathing, cough, sweating, fever, weakness, and painin the joints and muscles, lasting from 12 to 18 hours.

amoeba: A protozoan that has an undefined, changeable form and moves bypseudopodia (or branching fingers of cellular material).

amplification: In reference to microbes, this means an increase in the num-bers (generally due to growth and creation of elevated numbersindoors).

anaerobic: Not requiring the presence of oxygen for growth (e.g., Clostridium botulism, which causes canned food poisoning).

angioedema: This is a condition similar to urticaria (or hives), but involvesthe subcutaneous tissue. It ordinarily does not itch and is a moregeneralized swelling.

anisotropic: Substances having different refractive indices that depend onthe vibration direction of light.

ascospore: A haploid sexual spore created by the fungal class Ascomycetes(e.g., yeasts).

asthma: A disease that is characterized by recurrent episodes of difficultbreathing and by wheezing, with periods of nearly complete free-dom from symptoms.

atopic: Of or pertaining to a hereditary tendency to develop immediateallergic reactions, such as allergic rhinitis, allergic asthma, and someforms of eczema.

336 Glossary

autoimmune disease(s): A person’s immune system reacts against its owntissues and organs.

bagassosis: A form of allergic lung disorder caused by exposure to moldysugar cane fiber.

bake-out: A process whereby the temperature of a building is elevated toforce chemical off-gassing of building materials and furnishings.This is generally performed without building occupants, and theair is flushed with outside air after a predesignated time period.

basidiospores: Sexual spores created by the fungal class Basidiomycetes(e.g., common mushroom).

birefringence: The numerical difference in refractive indices for a substance.booklice (or book louse): Small, six-legged insects belonging to the order

Psocoptera that are implicated in paper dust allergies.bronchitis: An inflammation of the mucous membranes of the bronchial

tubes, characterized by difficulty breathing.carcinogenic: A substance capable of causing cancer.challenge test: A medical procedure, also known as provocative testing, used to

identify substances to which a person is sensitive by deliberately expos-ing the person to diluted amounts of the substance. A positive bronchialchallenge is one in which pulmonary function decreases.

chronic REL: Noncancer chronic reference exposure level developed byCalifornia EPA. These are inhalation concentrations to which thegeneral population, including sensitive individuals, may be exposedfor long periods of time (e.g., 24 hours a day for 10 years) without thelikelihood of serious adverse systemic effects.

commensal: Organisms that live in close association whereby one may ben-efit from the association without harming the other.

competition: Negative relationships between two populations in which bothare adversely affected with respect to their survival and growth.

conidia: Asexually produced spores which develop at the end of a conidio-phore (e.g., Penicillium).

conidiophore: The structure from which conidia develop.conjunctiva: The mucous membrane lining of the inner surfaces of the eye.conjunctivitis: Inflammation of the conjunctiva. This results in eye redness,

a thick discharge, sticky eyelids upon waking in the morning, andinflammation of the eyelids.

croup: An infection of the upper and lower respiratory tract that occurs pri-marily in infants and young children up to 3 years of age. It is char-acterized by hoarseness, fever, a distinctive harsh, brassy cough, ahigh-pitched sound when breathing, and varying degrees of respira-tory distress.

culturable: Viable (or live) microorganisms that can be grown.desorption: Process of running adsorbed liquids/gases from sorbent material.dispersion staining: Staining based upon the differences and similarities of

the refractive indices between a solid and liquid.

Glossary 337

dispersion: The separation of light into its color components by refractive ordiffracted light.

dust mites: Almost invisible to the naked eye, these eight-legged arachnidsare typically implicated in house dust allergies that are thought tobe associated with whole or portions of their bodies and feces. Theyare one of, if not the most common indoor allergens and are knownto cause asthma attacks, not dermatitis.

dyspnea: Difficulty breathing.eczema: A superficial dermatitis that, in the early stages, is associated with

itching, redness, fluid accumulation, and weeping wounds. It laterbecomes crusted, scaly, thickened, with skin eruptions.

emission factor: A single point quantitative measurement of gaseous or par-ticle emissions from a material, as determined by chamber testing.

emission rate: The actual rate of release of vapors/gases from a product overtime.

emphysema: A chronic disease of the lungs in which the alveoli are perma-nently damaged or destroyed. It is typically characterized by difficultbreathing and is associated with heavy, prolonged cigarette smoking.

endocarditis: Lesions of the lining of the heart chambers and heart valves.endotoxic shock: A body reaction caused by an endotoxin, generally charac-

terized by marked loss of blood pressure and depression of the vitalprocesses.

endotoxin: A toxin produced within bacteria and released upon destructionof the cell in which it was released.

environmental chamber: A nonreactive testing enclosure of known volumewith controlled air change rates, temperature, and humidity.

epitope: The portion of an antigen molecule involved in binding to theantibody.

farmer’s lung: A form of allergic lung disorder caused by exposure to moldyhay.

flush-out: Replace indoor serviced air with the outdoor air. The flush-outrate is the volume of outdoor air required to replace the same vol-ume of indoor air for each area serviced.

fomites: Inanimate objects (e.g., mineral dust particles).forensic: Relating to or dealing with the application of scientific knowledge

to legal issues.fungi: Plants that, unlike green plants, have no chlorophyll and must depend

on plant or animal material for nourishment.gastroenteritis: An inflammation of the stomach and intestines. It may at

times result from an allergic reaction.Gram negative: A staining process that is used in diagnostic bacteriology

whereby the bacterial wall is stained pink.Gram positive: A staining process that is used in diagnostic bacteriology

whereby the bacterial wall is stained purple, almost exclusively aproperty of producers of potent exotoxins.

338 Glossary

granuloma: A granulated nodule of inflamed tissue.hapten: A low molecular weight chemical that is too small to be antigenic by

itself but can stimulate the immune system when combined with alarger molecule (e.g., protein).

hay fever: Common name for “nasal allergy.” Its symptoms include attacks ofsneezing, runny, stuffy nose, and itchy, watery eyes, and they occurwithin a few minutes to a few hours after exposure to inhaled aller-gens, usually pollen, spores or molds, house dust, or animal dander.The term hay fever is misleading, since these reactions are not usuallyproduced by hay and are not accompanied by fever.

hemorrhagic shock: Physical collapse and prostration associated with sud-den and rapid loss of large amounts of blood.

heterologous (cross-reactive) antigen: A different antigen from that whichwas used to immunize or challenge the immune system, yet it issimilar enough to be recognized as the initial foreign substance.Typically, these antigens are polysaccharides, possibly due to theirlimited chemical complexity and often structurally similar in natureto one another. For example, human blood Group B sometimes reactswith antibodies to certain strains of Escherichia coli that are a com-mon bacterial resident in the human colon.

high-performance building: In accordance with American National StandardsInstitute (ANSI)/American Society of Heating, Refrigerating and AirConditioning Engineers (ASHRAE) Standard 189.1, a high-performancebuilding is “a building designed, constructed, and capable of beingoperated in a manner that increases environmental performance andeconomic value over time, seeks to establish an indoor environmentthat supports the health of occupants, and productivity of occupantsthrough integration of environmentally preferable building materi-als and water efficient and energy-efficient system” (not applicable tosingle-family homes, multifamily structures of three stories or fewerabove grade, manufactured homes, manufactured houses, and build-ings that do not have electricity, fossil fuel, or water).

hives (urticaria): A common skin condition that is probably familiar to every-one. It is a skin rash characterized by areas of localized swelling, usuallyvery itchy and red, and occurring in various parts of the body. It usuallylasts only a few hours and involves only the superficial areas of the skin.Urticaria has either an immunologic or a nonimmunologic cause.

homologous antigen: A foreign substance used in the production ofantiserum.

house dust: Heterogeneous, firm gray powdery material that accumulatesindoors. This category includes mold, pollen, animal dander, foodparticles, kapok, cotton lint, insects, and bacteria.

humidifier fever: Aerosolized microbial infection that causes flu-like symp-toms such as fever, headache, chills, muscle aches, and fatigue. Itusually subsides within 24 hours of onset.

Glossary 339

hybridized: Bound to a template of DNA sequencing.hypersensitivity pneumonitis: An inflammation of the alveoli within the

lungs caused by allergenic dusts.hypersensitivity: A condition in which the immune system reacts to anti-

gens that cause tissue damage and disease.hyphae: A microscopic filament of cells that represents the basic unit of a

fungus. They usually do not exist with yeasts.immune: A condition in which an organism is protected against, or free

from, the effects of allergy or infection, either by already having hadthe disease or by inoculation.

immunoglobulins: One of a family of proteins to which antibodies belong.in vitro: In an artificial environment.in vivo: In a live organism.incidence: Number of new diseases occurring in a given population at a

specified time period.isotropic: Substances showing a single refractive index at a given temperature

and wavelength, no matter what the direction of light may be.itch mites: Almost invisible to the naked eye, these eight-legged arachnids

cause itchy red marks and are sometimes implicated in house dustallergies but generally associated with straw, hay, grasses, leaves,and seeds.

ligase: Protein that acts as a glue to hold bits of DNA molecules together.lipids: Fats and fattylike materials that are generally insoluble in water.lymphocyte: A white blood cell important in immunity. Of the two major

types (both types have several subclasses), T-lymphocytes are pro-cessed in the thymus and are involved in cell-mediated immunity,and B-lymphocytes are derived from the bone marrow and are pre-cursors of plasma cells, which produce antibody.

macrophage: A scavenger white blood cell that plays a role in destroying invad-ing bacteria and other foreign material. It also plays a major role in theimmune response by processing or handling antigens and as an effec-tor cell (e.g., muscle or gland) in delayed hypersensitivity.

meningitis: An infection or inflammation of the membranes covering thebrain and spinal cord. Onset symptoms are characterized by severeheadache, stiffness of the neck, irritability, malaise, and restlessness,followed by nausea, vomiting, delirium, and disorientation. Thisprogresses to increased temperature, pulse rate, and respiration.Nerve damage may culminate in deafness, blindness, paralysis, andmental retardation.

micron (or micrometer): One millionth of a meter (10–6).mold: Microscopic plants, belonging to the fungi kingdom, which do not

have stems, roots, or leaves and are composed of a vegetative thread-like element (hyphae) and reproductive spores.

340 Glossary

monoclonal antibody: Antibody produced by a single clone of cells thatbinds to only one epitope.

mushroom: Microscopic plants, belonging to the fungi kingdom, that arefilamentous in nature with large fruiting bodies (referred to as themushroom cap) that discharge reproductive spores.

mutagenic: Capable of causing a genetic change.mycelium: A visible mass of tangled filaments of fungal cells, the rooting

structure and extension of the more aerial hyphae.mycotoxins: Toxins produced by molds.nanometer: One one thousandth of a micron, or one billionth of a meter

(e.g., 10–9).nasal congestion: Blockage of the nasal passages.necrosis: Localized tissue death.neutralism: A lack of interaction between two microbial populations.nonpolar compounds: Compounds that have atoms that do not have a denser

electron cloud about one atom, or group of atoms, than around itsadjoining atom, or group of atoms (e.g., hexane).

nonviable: Not living, dead, destroyed organisms; not capable of causingdisease.

nosocomial: Hospital-acquired infections.paper mites: Fictitious term with possible reference to storage mites or

booklice.parasitism: One population benefits and normally derives its nutritional

requirements from the population that is harmed.patch test: Used to identify substances responsible for contact allergy. The

test consists of applying a small amount of a suspected substance tothe skin. The area is covered with tape and left for forty eight hours.If is a small area where the substance was applied swells and turnsred, the test result is said to be positive.

Petri plate (or dish): A glass or plastic dish that has a lid, and it is used toisolate and grow microbes.

plasmids: Small loops of DNA in bacteria (contain genes for antibioticresistance).

pleurisy: Inflammation of the pleura (or membranous sacs surrounding thelungs).

polar compounds: Compounds that have atoms that have a denser electroncloud about one atom, or group of atoms, than around its adjoiningatom, or group of atoms (e.g., butanol).

pollen: Male fertilizing elements of a plant, which are microscopic in size.Pollen grains are spheroid, ovoid, or ellipsoid in shape and mayhave a smooth, reticulated (e.g., network), speculated (e.g., spikes orpoints), or sculptured surface.

predation: One organism, the predator, engulfs and digests another organ-ism, the prey.

Glossary 341

predicted air concentrations: A calculated prediction of air concentrations ofa given substance or substances, based on component emission rates.

prevalence: Normal frequency of a disease in a given population.prick method: An allergy test whereby the skin is pricked with a needle at

the point where a drop of allergen has been placed, introducing theallergen to the body’s immune system.

product loading: Ratio of the amount of material to be placed in an emis-sions test chamber to the volume of the chamber. The number may bebased on area (i.e., m2/m3), mass (i.e., g/m3), or unit (1 unit/m3).

pyrexia: A condition resulting in fever.pyrocanic: Sensation of heat.ragweed: A plant, belonging to the family Compositae, that is the major

cause of hay fever in the United States. The ragweed family is large,with approximately 15,000 species.

restriction enzymes: Proteins that cut apart DNA molecules.retractive index: The ratio of the velocity of light in a vacuum to the veloc-

ity of light in a given medium. A higher atomic number generallyresults in a higher refractive index.

rheumatic fever: An inflammatory disease that usually occurs in youngschool-aged children and may affect the brain, heart, joints, skin,or subcutaneous tissues. Early on, it is characterized by fever, jointpains, nose bleeds, abdominal pain, and vomiting, progressing tochest pain and, in advanced cases, heart failure.

rheumatoid arthritis: A chronic, destructive, often deforming, collagen diseasethat results in inflammation of the bursa, joints, ligaments, or muscles.It is characterized by pain, limited movement, and structural degen-eration of single or multiple parts of the musculoskelatal system.

rhinitis: A disease of the nasal passages that is characterized by attacksof sneezing, increased nasal secretion, and stuffy nose (caused byswelling of the nasal mucosa).

rust: A fungal disease of agricultural crops so named because of the orange-red color it imparts to infected plants. Belongs to the same fungalclass as the common mushroom.

saponification: The hydrolysis of an ester by an alkali, producing a free alco-hol and an acid salt.

saprophytic: Lives on and derives its nourishment from dead or decayingorganic matter.

scratch test: A small drop of an allergen is applied over an area of the skinwhere a superficial scratch has been made. This allows the allergento penetrate the top layer of skin.

semivolatile: Compounds with a boiling range of 240°C to 400°C.sensitize: To administer, or expose, to an antigen provoking an immune

response so that, upon later exposure to that antigen, a more vigor-ous secondary response will occur. An individual can be immune(e.g., protected against the effects of an infectious agent or antigen)

342 Glossary

and sensitized to the antigen (e.g., demonstrate a positive tuberculinreaction) at the same time.

septicemia: Systemic infection where pathogens are spread through thebloodstream, infecting various parts of the body, characterized byfever, chills, prostration, pain, headache, nausea, and diarrhea.

skin test: A method of testing for allergic antibodies. A test consists of intro-ducing small amounts of the suspected substance, or allergen, intothe skin and noting the development of a positive reaction (whichconsists of a wheal, swelling, or flare in the surrounding area of red-ness). The results are read 15 to 20 minutes after application of theallergen.

slime mold: Organisms, belonging to the fungi kingdom, that are protozoan-like for part of their life cycle and reproduce by forming stalks thatproduce spores (or multiple spore-containing sporangia).

smut: A fungal disease of agricultural crops so named because of the sootyblack appearance it imparts to infected plants. Belongs to the samefungal class as the common mushroom.

sorbent: A solid or liquid material that collects liquid or gaseoussubstances.

sporangiospores: Asexually produced spores that develop within asporangium.

sporangium: A structure, or sac, within which spores develop.spores: Reproductive cells of certain plants and organisms. Inhaled fungal

spores are frequently the cause of allergic symptoms such as rhinitisand asthma.

storage mites: Four-legged arachnids that are sometimes implicated inoutdoor environmental allergies associated with agriculturalenvironments.

symbiotic: Obligatory relationship between two populations that benefitsboth populations.

synergistic: Mutually cohabitate with one another.teleospores: Asexual spores produced by rusts.thymine: A DNA base that only pairs to the base adenine.tobacco sensitivity: Many people suffering from rhinitis and asthma experi-

ence heightened symptoms when exposed to tobacco smoke.transparency: Ability to transmit light.ulceration: Formation of a circular, craterlike lesion of the skin or mucous

membranes.unculturable: Viable and nonviable microorganisms that cannot be grown.urediospores: Asexual spores produced by smuts.urticaria (hives): This is a skin rash characterized by areas of localized

swelling, usually very itchy and red, and occurring in various partsof the body. It usually lasts only a few hours and involves only thesuperficial areas of the skin.

Glossary 343

viable: Living organism; capable of causing disease. In reference to mold,viable means the spores that will grow, given the proper growthmedia.

viron: An intact virus particle that has the ability to infect.virus: A submicroscopic organism that consists of genetic material and a

coating and requires living organisms in order to reproduce.viscera: The internal organs enclosed within a body cavity, primarily the

abdominal organs.Volatile organic compound(s): Organic compounds that vaporize at rela-

tively low temperature.volatile: Compounds with a boiling range of 0°C to 290°C.xerophilic: Organisms that grow where there is low water availability.yeasts: Species of fungi that grow as single cells.zeophylic: Dry-loving organism.

345

Appendix A: Abbreviations/Acronyms

AAAAI: American Academy of Allergy, Asthma, and ImmunologyACGIH: American Conference of Governmental Industrial HygienistsAGI: All glass pingerAHU: Air Handling UnitAIDS: Auto Immune Deficiency SyndromeANSI: American National Standards InstituteASHRAE: American Society of Heating, Refrigerating and Air-conditioning

EngineersBA: Blood AgarBIFM: British Institute of Facilities ManagementCDC: Center for Disease ControlCFM: Cubic Feet per MinuteCFR: Code of Federal RegulationsCFU: Colony Forming UnitsCIH: Certified Industrial HygienistCO: Carbon monoxideCO2: Carbon dioxideCREL: Chronic Reference Exposure LimitCRI: Carpet and Rug InstituteDNPH: DinitrophenylhydrazineDOT: Department of TransportationEDX/EDXRA: Energy Dispersive X-Ray AnalyzerEMA: Electron Microprobe AnalyzerEPA: Environmental Protection AgencyEU: Endotoxin UnitsFDA: Food and Drug AdministrationFID: Flame Ionization DetectorFTIR: Fourier Transform Infrared SpectrometryGC: Gas ChromatographyGC/ECD: Gas Chromatography/Electron Capture DetectorGC/FID: Gas Chromatography/Flame Ionization DetectorGC/MS: Gas Chromatography/Mass SpectrometryGC/NPD: Gas Chromatography/Nitrogen Phosphorous DetectorGC/NSD: Gas Chromatography/Nitrogen Selective DetectorGEN: Global Ecolabelling NetworkHEPA: High Efficiency Particulate AirfilterHPLC: High Pressure Liquid ChromatographyHPLC/UV: High Pressure Liquid Chromatography/UV DetectorHRP-SA: Horseradish Peroxidase-StreptavidinHUD: Housing and Urban Development

346 AppendixA

HVAC: Heating, Ventilation, and Air ConditioningIAQ: Indoor Air QualityIC: Ion ChromatographyIMA: Ion Microprobe AnalyzerIP: Indoor Pollutant Methods (EPA)KLARE: Kinetic-Turbidimetric Limulus Assay with Resistant-parallel-line

Estimates (Test)LEED: Leadership in Energy and Environmental DesignLEL: Lower Explosion LimitMPI: Mass Psychogenic IllnessMSDS: Material Safety Data SheetMVOC: Microbial/Mold Volatile Organic CompoundsNA: Not ApplicableNAB: National Allergy Bureau (Program under the American Academy of

Allergy, Asthma, and Immunology)NIOSH: National Institute for Occupational Safety and HealthNPD: Nitrogen Phosphorous DetectorOSHA: Occupational Safety and Health ActOVA: Organic Vapor AnalyzerPCH: 4-PhenylcyclohexenePID: Photoionization DetectorPM2.5: Particulate matter with an aerodynamic diameter less than or equal

to 2.5 microns (respirable)PM10: Particulate matter with an aerodynamic diameter less than or equal

to 10 microns (thoracic)ppb: parts per billionppm: parts per millionppt: parts per trillionRBA: Rose Bengal AgarRH: Relative HumidityRT: Room TemperatureSAED: Selected Area Electron DiffractionSEM: Scanning Electron MicroscopyTCLP: Toxicity Characteristic Leaching ProcedureTEM: Transmission Electron MicroscopyTLV-TWA: Threshold Limit Value-Time-Weighted AverageTO: Toxic Organic Methods (EPA)TSA: Tryptic Soy AgarTVOC: Total Volatile Organic CompoundsUEL: Upper Explosion LimitVAS: Visual Absorption SpectrometryVAV: Variable Air VolumeVOC: Volatile Organic CompoundWHO: World Health Organization

347

Appendix B: Units of Measurement

Volume

1 liter (L) = 1.06 quarts1 milliliter (mL) = 10–3 liter1 microliter (µL) = 10–6 liter

Length

1 meter (m) = 3.281 feet = 39.37 inches1 centimeter (cm) = 10–2 meter = 0.039 inch1 millimeter (mm) = 10–3 meter1 micrometer (µm) = 1 micron (p) = 10–6 meter

Weight

1 gram(s) (g) = 0.035 ounce1 milligram (mg) = 10–3 gram1 microgram (µg) = 10–6 gram1 nanogram = 10–9 gram1 picogram = 10–12 gram

Temperature

1° Fahrenheit (F) = [(1.8) (X°C)] + 321° Centigrade (C) = [X°F – 32]/1.8

348 AppendixB

Sample Units

ppm = parts of contaminant per million parts of sample material (e.g., air)ppb = parts of contaminant per billion parts of sample materialppt = parts of contaminant per trillion parts of sample materialmg/m3 = milligrams of contaminant per cubic meter of sample materialpg/m3 = micrograms of contaminant per cubic meter of sample materialgrains/m3 = grains of pollen per cubic meter of air sampleCFU/m3 = colony forming units per cubic meter of airmg/m2-hour = milligrams of contaminant per square meter of material in

one hourmg/X-hour = milligrams of contaminant per item, or composite unit, (X) in

one hour of emissions testingmg/hour-m3 = milligrams of contaminant emitted in one hour within a three

cubic meter spaceµg/X-hour = micrograms of contaminant per item, or composite unit, (X) in

one hour of emissions testing

Flow Rates

cubic centimeter per minute (cc/min)liter per minute (Lpm)milliliters per minute (mL/min)

349

Appendix C: Allergy Symptoms

Common Allergy Symptoms

Many of the allergy symptoms are commonly known and understood. Yetsome are not acknowledged by the general public. Improperly interpretedallergy symptoms may result in a search for other causes of a given symptomother than allergens. The investigator should be familiar with the symptomsas presented herein.

Allergic Asthma

Asthma generally results when cold air, pungent odors, viral infections, aspi-rin and related drugs, inert dusts, or allergens cause hyperactivity of the air-ways with narrowing of the air passages. This is translated into a tighteningsensation of the chest and breathing difficulties associated with coughing andwheezing. Movement of the chest-wall muscles may be felt as a heavy weight,a constriction of the lungs. If complications involve the pneumothorax, ribfracture, or pneumonia, chest tightness becomes pronounced and painful.Breathing could become excruciating and resemble symptoms of pleurisy.

Strenuous exercise may also heighten the severity as exposure levelsincrease. In severe episodes, the sufferer may also experience wheezing andmental dullness due to reduced oxygen inspired/delivered to the brain.

If a person has been relatively free of asthma until exposure to animals,cut grass, or a virus, and if the exposure is brief, the attack should subsidewith proper treatment. It may even subside spontaneously.

Allergic Dermatitis

Although acute symptoms of allergic dermatitis are not singularly diagnostic,they characteristically involve itching, redness, swelling, and a scaly rash.

Itching can be intense and may lead to what is known as weeping lesions,caused by the serum oozing from the underlying small blood vessels. Typicalareas of the body for this to happen are the cheeks, the creases behind theears, and at the bends of the arms and legs.

Commonly called eczema or atopic dermatitis, the rash can spread enoughto become disabling. During the healing stage, the affected skin thickens,becomes dry, and cracks. Some bleeding may also occur during this stage.

350 AppendixC

A local infection that takes the form of skin boils is serious and should beconsidered a threat to the comfort of the individual. As their immune systemhas yet to develop completely, infants and young children may not demon-strate as severe a reaction as an adult. They may simply develop a red, flat,scaly rash without the annoyance experienced by older individuals.

Allergic Rhinitis

Allergic rhinitis is characterized by nasal congestion and sneezing, whichare, in turn, associated with irritation of the throat, eyes, and ears.

Eye Pain

Allergic conjunctivitis can induce a painful, burning condition known aspink eye. Bright light often adds to the discomfort, leading the individual toappear to be afraid of light. Severe watering and squinting may occur.

Hay Fever

When symptoms are seasonal, allergic rhinitis is referred to as hay fever.Such allergens include pollen and mold spores. Itching of the nasal passagesis a common symptom associated with pollen and mold spores. In an attemptto relieve the discomfort, a sufferer frequently performs nose-rubbing ritualsand facial contortions. Itching of the roof of the mouth and inner corner ofthe eyes may further contribute to demonstrations of distress.

Inner Ear Pain and Hearing Loss

Allergic rhinitis is associated with extensive fluid leakage into the middleear. Fluid buildup causes an aching pain that can temporarily diminishhearing. If untreated the condition can cause fever and increased pain, andlead ultimately to rupture of the eardrum.

Nasal Congestion

Nasal congestion may result in breathing difficulties due to blockage of thenasal passages. Congestion may also result in a watery, blood-flecked dis-charge either from the nose or back of the throat. Some allergy sufferersdescribe a tickle of the throat. Drainage and throat irritation provoke cough-ing and other indirectly related problems.

When nasal blockage occurs, allergy sufferers tend to breathe through theirmouths and frequently lose sleep. The problem thus culminates in fatigueand irritability. Although these symptoms are associated with allergies, it isimportant that the environmental professional be aware that they may be theresult of other problems that may require a physician.

AppendixC 351

Not all nasal discharges are caused by allergies. Simple colds or virusinfections may simulate allergic disease. Allergic disease is not normallyaccompanied by the presence of fever, general aching, and a yellow or greennasal discharge. When exposed to unusually high levels of an allergen, anallergy sufferer may develop a systemic reaction where general aching isthe primary symptom. Yellow or green nasal/throat discharges are gen-erally associated with viral or bacterial infections, and an infection lastsabout two weeks. An allergic condition comes and goes with environmen-tal changes.

Another cause of congestion that should not be confused with allergicrhinitis is that which is caused by a tumor obstruction. Nasal blockage mayresult from polyps—normal or malignant growths of sinus and nasal tis-sue filled with fluid, which may or may not be the result of allergy-causedpostnasal drip. If the blockage persists unabated for several days, both lossof smell and nasal/sinus infections may result.

Sinus Headache

Sinus obstruction results in area related headaches. The sinuses have outletsor air spaces through the nasal passages. These air spaces are located nearthe nose, under the cheeks, and above the eyes. When the spaces becomeobstructed, buildup of air or fluid leads to increased pressure, resulting inpain. This pain may range from a dull discomfort to a sharp, steady ache inthe areas involved (e.g., above the eyes). This is referred to as a sinus head-ache, or sinusitis.

Other Allergy-Related Diseases

Some rare forms of allergy-related illness occur in less than 1 percent of theUnited States population. Awareness concerning some of their symptomsmay be relevant to an overall investigation of environmental impact of air-borne allergens. These are discussed herein.

Allergic Bronchopulmonary Aspergillosis

Allergic bronchopulmonary aspergillosis is, as the name implies, an allergicdisease that involves exposures to the fungus Aspergillus. Aspergillus fumigatus is generally the species implicated. This disease involves invasion of themucous lining of the air passages within the lungs. Affected individuals mayexperience a persistent cough associated with sputum, asthmalike symp-toms, fever, and chest pain. Viable spores are the initiator and, once invasionhas occurred, the disease is progressive until treatment is administered.

352 AppendixC

Contact Dermatitis

Contact dermatitis involves an itchy, red rash that is generally confined tothe site of exposure. Scratching may lead to blistering. Although the areasimpacted are commonly exposed skin surfaces, exposures may result fromtransference of allergen from one place to another (e.g., scratching unexposedskin surfaces with contaminated fingernails). The most common exposuresare to oils from poison ivy and poison sumac, which if burned may becomeairborne or are spread by contact with weeping sores. Removal from andavoidance of the allergen will, in most cases, provide relief within two weeksif the affected areas are left alone.

Hives

Hives, or urticaria, are generally associated with food or drugs. On rareoccasions they may be associated with animal allergens, skin contact withthe mold Penicillium, and Hevea brasiliensis latex. Raised bumps may appearanywhere on the body. These may range in size from that of a small peato large sections of the body and are often accompanied by red haloes anditching. Each lesion may last only a few hours, but new ones can appear atfrequent intervals, and itching may become so intense that it is difficult toperform simple tasks or sleep.

Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis, or allergic alveolitis, generally involves anoccupationally related inflammation of the alveoli and bronchioles of thelungs. Acute pneumonitis (short term, extremely high exposures) results inbreathlessness, chills, and fever. Fever may be as high as 104°F, and, withinfour to six hours symptoms progress into muscle aches and moodiness. Chestx-rays may show diffuse nodular shadows that are predominately found inthe lower portions of the lungs.

Subacute symptoms occur upon repeated exposures and appear as chronicbronchitis. This phase is characterized by repeated exposures and by recur-ring cough, breathlessness, weight loss, and malaise.

Chronic exposures to low levels of antigenic material may be demon-strated by less obvious symptoms. The allergy sufferer may only expe-rience breathlessness and weight loss, but the chest x-rays will revealprogressive scarring. Pulmonary function tests will show declining func-tional lung volume. Diagnostic confirmation of the various stages of thedisease generally requires the aid of a physician. Common occurrenceof the disease is typically limited to bird handlers and to farmers in thesoutheast. Disease is generally associated with a known source and isregion dependent.

353

Appendix D: Classification Volatile Organic Compounds

Alcohols

Due to its association with cosmetics, the more commonly found alcoholin indoor air quality is isopropanol. Alcohols are most frequently used assolvents, perfumes, components of pharmaceuticals (e.g., cough medicine),cleaning agents (e.g., packaged as hand wipes), and fuel additives. The ali-phatic alcohols have a distinct “alcohol” odor, and the aromatic alcohols havemore of a medicinal or creosote odor.

Low-level exposures to aliphatic alcohols may result in irritation of theeyes and upper respiratory tract, occasionally headache and dizziness. Thelowest 8-hour exposure for volatile alcohols is 1 ppm (American Conferenceof Governmental Industrial Hygienists [ACGI] limit for propargyl alcohol).Airborne exposures to alicyclic and aromatic alcohols may result in irritationof the eyes and upper respiratory tract, anorexia, weight loss, weakness, andmuscle aches and pain.

Aldehydes

The aldehydes are commonly encountered in indoor air quality. They aremost frequently used as cleaning agents, biocides, and constituents of resins.Odors have been described as sharp, pungent.

The aldehydes follow the First Member Rule in that formaldehyde is themost toxic of the group. Although not as common as many people wouldsuspect, formaldehyde has been known to cause skin sensitization that maydemonstrate itself in a fashion like poison ivy, and formaldehyde is a suspecthuman carcinogen. Airborne exposures to aldehydes may result in irritationand a burning sensation of the eyes, upper respiratory tract, and skin.

354 AppendixD

Aliphatic and Alicyclic Hydrocarbons

Many of the volatile organic compounds (VOCs) found in indoor air qualityare aliphatic (e.g., methane) and alicyclic (e.g., cyclohexane) hydrocarbons.Methane, an aliphatic, is evolved during the animal and plant decay, andit is encountered in the atmosphere typically at levels of 1.8 ppm. Many ofthe aliphatics and alicyclics are components of gasoline, and they are usedfor heating, welding, illumination gases, refrigeration, and solvents. The ali-phatics and alicyclics do not have an odor.

With a low toxicity, the principal effect of aliphatic and alicyclic VOCs isnarcosis at very high exposure levels, in excess of what would normally befound in indoor air quality. Symptoms may include lightheadedness, head-ache, and irritation of the eyes and nose.

Aromatic Hydrocarbons

Most of the more commonly encountered organics in indoor air quality are vol-atile aromatic hydrocarbons. Aromatics are most frequently used in solvents,and they are a component of gasoline. They have a pleasant, “aromatic” odor.

The aromatic hydrocarbons follow what is referred to as the “First MemberRule.” This rule states that the toxicity of the first member of a homologousseries is likely to differ qualitatively from the toxicity of the other membersof the same series. For instance, benzene, the first member in the aromatichydrocarbon series, is the more toxic of the aromatics, causes damage to theblood cell-forming system, and is a suspect human carcinogen. The otheraromatics are neither as toxic, nor known to cause the same extreme healtheffects as benzene.

The health effects associated with aromatic VOCs at low levels antici-pated in nonindustrial environments are narcosis and moderate irritation.Symptoms may include fatigue, weakness, dizziness, headache, and irrita-tion of the eyes, nose, and throat.

Esters

Esters are occasionally encountered in indoor air environments. They aremost frequently used as solvents, and commonly found in highlighter pens.Esters have sweet, variable odors (e.g., bananas or wintergreen) and are often

AppendixD 355

used for food. Airborne exposures to esters may result in irritation of theeyes and upper respiratory tract and narcosis. Symptoms may include head-ache and throat irritation.

Ethers

The ethers are rarely encountered in indoor air environments. They are anarcotic and frequently used for anesthesia and have been used in solvents,making gun powder, refrigerant, and aerosol propellant. Odors have beendescribed as sweet and pleasant.

Low-level exposures to glycol ethers may result in irritation of the eyes andupper respiratory tract. The lowest 8-hour exposure for volatile alcohols is400 ppm (ACGIH limit for ethyl ether).

Glycol Ethers (i.e., Cellosolves)

The glycol ethers are occasionally encountered in indoor air environments.They are most frequently used as solvents (referred to by the trade name ofCellosolves) in dry cleaning, nail polishes, varnishes, and enamels. Odorshave been described as sweet and musty. Airborne exposures to glycol ethersmay result in irritation of the eyes and upper respiratory tract.

Halogenated Hydrocarbons

Other than the ubiquitous Freon, the volatile halogenated hydrocarbonsare less frequently encountered in indoor air environments. They are mostfrequently used as solvents. Halogenated hydrocarbons have a faint sweetodor.The halogenated hydrocarbons follow the First Member Rule in thathalogenated methanes (e.g., methyl bromide and chloroform), ethanes (e.g.,vinyl bromide), and benzenes (e.g., benzyl chloride) are the more toxic of thegroup. They are narcotic, can cause liver and kidney damage, depression ofthe bone marrow activity, and are suspected human carcinogens. Airborneexposures to all other halogenated hydrocarbons may result in headache,dizziness, and nausea.

356 AppendixD

Ketones

Ketones are occasionally encountered in indoor air environments. Theyare most frequently used as solvents. They are also used in antifreezesolutions and hydraulic fluids. The most commonly found ketones inindoor air are acetone and methyl ethyl ketone. Ketones have a faint pleas-ant odor. Airborne exposures to ketones may result in irritation of the eyesand upper respiratory tract and narcosis. Symptoms may include headacheand throat irritation as well.