airborne contaminants lab

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Airborne Contaminants Lab

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Airborne Contaminants Lab. Topics. Overview of workplace health and its regulation Particulates and microscopy Gases and vapors Monitoring Real time Noise. Format. Lecture with break Break Hands-on, with Sheila M Simmons Environmental Health, Safety, and Risk Management - PowerPoint PPT Presentation

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Page 1: Airborne Contaminants Lab

Airborne Contaminants Lab

Page 2: Airborne Contaminants Lab
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Topics

• Overview of workplace health and its regulation

• Particulates and microscopy

• Gases and vapors– Monitoring– Real time

• Noise

Page 6: Airborne Contaminants Lab

Format

• Lecture with break

• Break

• Hands-on, with Sheila M Simmons

• Environmental Health, Safety, and Risk Management

• http://www.uaf.edu/safety/

Page 7: Airborne Contaminants Lab

Practical Application

• The terms– “Environmental Engineering” – “Environmental work

• Often extend to analyzing the workplace environment for contaminants– hence offering opinions on human health– firms often practice in this area.

Page 8: Airborne Contaminants Lab

Alphabet Soup

• EPA

• OSHA

• NIOSH

• AIHA

• ACGIH

Page 9: Airborne Contaminants Lab

Alphabet Soup

• OSHA, Occupational Safety and Health Administration

• NIOSH, National Institute of Occupational Safety and Health

• AIHA, American Industrial Hygiene Association

• ACGIH, American Conference of Governmental Industrial Hygienists.

Page 10: Airborne Contaminants Lab

OSHA and NIOSH

• Created in 1970’s by same act of congress• MSHA was earlier,

• OSHA– Law enforcement– Department of Labor

• NIOSH– Science– Center for Disease Control in PHS.

Page 11: Airborne Contaminants Lab

AIHA and ACGIH

• Industrial hygiene = science of workplace health

• AIHA accredits laboratories

• ACGIH produces TLV’s– “safe values”

Page 12: Airborne Contaminants Lab

Occupational Standards

• OSHA, PELs– (CFR, code of federal regulations, on line)– PELs

• ACGIH, TLVs

• NIOSH, RELs

• DFK, MAKs

Page 13: Airborne Contaminants Lab

TLVs

• Of the approximately 450 standards– 15% have human or otherwise well tested– 25% have some animal testing– 60% Based on “analogy,” “supposed,” or

“traditional.”

Page 14: Airborne Contaminants Lab

OSHA

• OSHA main site OSHA – 1910 Subpart Z– 1910.1000

• History of Tables– ANSI list– lawsuits

Page 15: Airborne Contaminants Lab

Contaminant Particulates

• Asbestos

• Quartz

• Dust

Page 16: Airborne Contaminants Lab

Asbestos is useful

• Asbestos used since ancient times• Fireproof

• WW II ship building• Insulation

• 1950’s Schools• Sound proofing,

• Many materials• Strength of fibers, chemical resistant

Page 17: Airborne Contaminants Lab

Asbestos kills• About 10,000 persons die each year from

asbestos related disease– 1,000 from mesothelioma– 4,000 from asbestosis– 5,000 from lung cancer

• (correlated with cigarette smoking)

• 20 to 40 year latency period• Airborne fibers, not parent material

Page 18: Airborne Contaminants Lab

Asbestos is regulated

• OSHA regulates workplace exposures

• EPA regulates schools

• EPA regulates disposal process

Page 19: Airborne Contaminants Lab

Asbestos Minerals

• Asbestos is a commercial term– Polysilicate minerals

Insert SiO4:Insert SiO4:

Page 20: Airborne Contaminants Lab

10 u +/-

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Amphiboles• Amosite (Mg, Fe)

• Actinolite (Ca, Mg, Fe)

• Anthophyllite (Mg, Fe)

• Crocidolite (Na, Fe+++, Fe++)

• Tremolite (Ca, Mg)

Page 22: Airborne Contaminants Lab

Serpentine• Chrysotile (Mg)

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Respiratory Tract

• Anatomy

• Physiology

• Notes on the asbestos diseases

Page 24: Airborne Contaminants Lab

Asbestosis

• Fibrotic lung disease

• Lungs fill with scar tissue– restrictive lung disease, stiff– oxygen transport reduced– breathing labored

Page 25: Airborne Contaminants Lab

Gallery

• Boston University School of Public Health

• Breath Taken: The Landscape & Biography of asbestos

• http://www/busph.bu.edu/Gallery

Page 26: Airborne Contaminants Lab

Normal Lung:Normal Lung:

Page 27: Airborne Contaminants Lab

HoneycombingHoneycombing

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AsbesosisAsbesosis

Page 29: Airborne Contaminants Lab

Asbestos, clubbing of fingers

Asbestos, clubbing of fingers

Page 30: Airborne Contaminants Lab

Hairdresser, combed from hair

Hairdresser, combed from hair

Page 31: Airborne Contaminants Lab

Mesothelioma

• Cancer of the lining of the abdominal cavity

• Or thoracic cavity

• Fatal

Page 32: Airborne Contaminants Lab

childhood exposure father worked in plant and died of asbestosis note tumor on right side, fills with fluid

childhood exposure father worked in plant and died of asbestosis note tumor on right side, fills with fluid

Page 33: Airborne Contaminants Lab

• Mesothelioma is a rare cancer

• 2 deaths per million populations

• But in a study of asbestos insulation workers there were 175 deaths from mesothelioma.

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Lung Cancer

• 32 of 41 studies indicated statistically significant increase in lung cancer of asbestos workers

• Non-smokers were 5-fold higher than non-exposed

• Smoking asbestos workers were much higher 50- to 90-fold

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Toxicology, Fiber type• Some studies indicate chrysotile can

cause mesothelioma

• Most indicate amphiboles, especially crocidolite

• Some authors have concluded amphiboles are 100 times more potent than chrysotile in inducing mesothelioma.

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particle

fiber

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Clearance and fiber size• Residents of cities breath several hundred

grams of particles over a lifetime• Only a few grams at autopsy• Most are cleared from lung• Sorting in the airways by aerodynamic

diameter• Thin fibers penetrate much deeper than

round particles of similar diameter

Page 45: Airborne Contaminants Lab

Clearance mechanism by location of deposition

• Nasal clearance: – in from of ciliated, by sneezing or blowing– further back swept down and swallowed

• Tracheobronchial: cleared via cilia– mucociliary escalator

• Alveolar– macrophage

Page 46: Airborne Contaminants Lab

Macrophages

• Digest particles

• Carry towards ciliated airway

• Can wind up in lymph nodes and elsewhere– especially is “surface” route is overwhelmed

Robins pg. 757Robins pg. 757

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Macrophage

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Macrophage

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Clearance

• Fibers less than 1 micron cleared half-life of 10 days

• Fibers longer than 16 micron, half-life over 100 days

• Maximum fiber length of one macrophage about 16-17 microns

Page 50: Airborne Contaminants Lab

Disease vs. fiber length

• Animal studies

• Dust rich in f < 5 less lung cancer

• Dust rich in f > 5 more lung cancer

• Asbestosis associated f > 2 • Lung cancer f > 5 • Mesothelioma f > 10

Page 51: Airborne Contaminants Lab

Dose-Response

• Measured in fibers per cc

• f/cc

• Usually states “longer than 5 u.”

• EPA uses “structures” for some purposes

• but

• Disease incidence is proportional to exposure.

Page 52: Airborne Contaminants Lab

Dose-Response

• 10 f/cc-yr has been suggests as threshold for asbestosis. (0.2 f/cc for 50 years)

• OSHA PELs (over 5 microns)– 12 f/cc in 1971

– 5 f/cc in 1972

– 2 f/cc in the early 1980’s

– 0.2 f/cc in 1986

– Now 0.1 f/cc.

Page 53: Airborne Contaminants Lab

Dose-Response, Epidemiology

• Lowest dose that produced tumors

• 16 of 19 studies lowest dose was > 10 f/cc yr

• 14 of 19 studies lowest dose was > 20 f/cc yr

• 3 studies lowest dose was < 10 f/cc yr

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Dose-Response, estimated• For 1 excess lung cancer / 10,000 [ATSDR]• For environmental (24 hrs, 365 days)

– 0.35 f/cc yr (non-smokers)

• For workers (40 hrs, 50 weeks)– 1.5 f/cc yr– 0.1 f/cc for 15 yrs– 0.05 f/cc for 30 yrs

• OSHA uses 1 / 1000 for “significance,” sometimes.

Page 55: Airborne Contaminants Lab

ACGIH TLVs

• Amosite 0.5 f/cc, A1

• Chrysotile 2.0 f/cc, A1

• Crocidolite 0.2 f/cc, A1

• “Other forms” 2.0 f/cc, A1

• (New TLV’s do not distinguish fiber type

Page 56: Airborne Contaminants Lab

Toxicity, Summary

• Airborne asbestos fibers are a significant health hazard

• 0.1 f/cc (OSHA PEL) for mixed fiber types is reasonable

• Chrysotile is less toxic than amphiboles

• Fibers less than 5 microns long are less toxic than fibers over 16 microns

Page 57: Airborne Contaminants Lab

Microscopy

• PCM phase contrast microscopy– and more PCM– NIOSH 7400– workhorse

• Cheap, done on job

• count all fibers longer than 5 microns

– Does not distinguish asbestos from non-asbestos

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PCM of Fiber Bundle

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Microscopy

• TEM transmission electron microscopy– can distinguish asbestos fibers and their mineral

type– expensive (10-15 times PCM)– can count small fibers

• Beam of electrons from bottom– just like PCM

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TEM of virus

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SEM

• Scanning Electron Microscopy– Shines the electrons in from the top– Scans– Shows surface features.

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SEM

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Microscopy

• PLM polarized light microscopy– can distinguish asbestos from non-asbestos– not used for air samples– yields percentage of asbestos fibers in bulk

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• Most minerals are translucent (i.e., if the mineral grain is thin enough then the light will pass through).

• Analyst examines light that passes through a given sample

• It has interacted with the internal structure of the mineral grains.

• The light emerges from the sample it has been altered due to interactions within the mineral grains.

• Each mineral is unique in its composition and/or structure so each mineral has a unique affect on light when it passes through it.

• Thus interpreting the emergent light allows a geologist to identify minerals with great accuracy.

Page 66: Airborne Contaminants Lab

PLM of fibers

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Microscopy

• NIOSH 7400/7402– uses TEM to determine % of asbestos in PCM– standard method (“OSHA hybrid” similar)

• EPA Level II– TEM– measures small fibers (< 5 microns) as well as

larger

Page 68: Airborne Contaminants Lab

Summary of Microscopes

• PCM, Phase Contrast Microscope– 400 X, transparent

• PLM, Polarized Light– 400 X, mineral identification

• Binocular– 400 X, dissection and gross identification

• TEM– very powerful, expensive, identification

• SEM– vivid pictures

Page 69: Airborne Contaminants Lab

Quartz

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Quartz

• Silicon dioxide (SiO2)• Occurs in a crystalline or noncrystalline

(amorphous) form. • Crystalline silica may be found in more

than one form (polymorphism). • The polymorphic forms of crystalline

silica are alpha quartz, beta quartz, tridymite, cristobalite, keatite, coesite, stishovite, and moganite

• Some more toxic than others

Page 71: Airborne Contaminants Lab

Inhalation of Quartz

• silicosis, kills 200 – 300 each year

• pulmonary tuberculosis (TB), lung cancer, and scleroderma.

• A rare multisystem disorder characterized by inflammatory, vascular, and fibrotic changes usually involving the skin, blood vessels, joints, and skeletal muscle

Page 72: Airborne Contaminants Lab

Silicosis

• Silicosis is similar to asbestosis and emphysema, a scarring and hardening of the lungs

• Mediated by auto-immune problems• Can kill relatively quickly in sensitive

individuals, – 2 to 5 years of exposure– sandblasters (“sand” no longer used in US.)

Page 73: Airborne Contaminants Lab

Monitoring Silica

• Particles size

• Crystal structure

• Use special techniques– XRD Spectrometry – IR Spectrometry – Colorimetric Spectrophotometry

Page 74: Airborne Contaminants Lab

Dust

• Nuisance Dust

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How to collect samples

• Draw known amount of air over a filter.• Filter traps particles• Dissolve filter for PCM

– material must permit

• For silica, use cyclone to separate respirable particles

• For dust, must weight filter before and after– Use PVC filter

• More on air volume a little later.

Page 76: Airborne Contaminants Lab

How about gases

• Hundreds on list(s)

• What are we monitoring

• And Why?

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What Chemical

• Do we know?

• Liquid

• Gas

• Particle

Page 78: Airborne Contaminants Lab

Chemical Properties

• Major division– Hydrophobic vs. hydrophilic

• Reactive or

• Flammable

• Explosive

• Other chemicals present

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Process characteristics

• Sudden releases

• Ambient

• History

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Receptor characteristics

• Most highly exposed worker

• All workers

• Area

• Work tasks– exertions– clothing

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Exposure route

• Inhalation

• Dermal

• Ingestion

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Air contaminant terms

• Gas– gas at NTP

• Vapor

• fume

• aerosol

• fog

• smog

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Health Hazards

• Asphyxiation

• Narcosis

• Chronic toxicity

• Acutely toxic

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Once you know where you are going

• Regulations may specify

• Manufactures and suppliers literature

• Industrial hygiene professional(CIH)

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Two main divisions

• Air sampling– Take a sample and analyze elsewhere

• Direct reading– real time

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Explosive

• Sampling or Direct?

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Sampling Objective

• Documenting exposures

• Regulation compliance

• Pinpointing sources

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Acute Hazard

• Alarms

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Chronic hazard

• Usually health

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Summary of sampling method criteria**

• Sampling Objective

• Physical and chemical characteristics of chemical

• Presence of other chemicals

• Required accuracy and precision

• Regulatory requirements

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Summary of sampling method criteria, cont.**

• Portability and ease of operation

• Cost

• Reliability

• Type: area, personal, grab, integrated, etc.

• Duration of sampling and program.

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Air sampling devices

• Collect and take to laboratory

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6-9”

Breathing zone

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Suction pump

Flow rate control

Sampling Train

Collection device

Air inlet orifice

Airflow meter

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Grab vs. Integrated

• Vacuum bottles

• Bags

• http://www.skcinc.com/prod/tsb.html

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Integrated

• Absorption• Adsorption• Filters

– Cyclones– Electrostatic– Inertial– Impinger– Elutriators

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Absorption

• Highly soluble and non-reactive

• Reactive

• Similar– Gas wash– spiral– fritted glass– glass beads

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Gas Washing

http://www.skcinc.com/prod/impinger.html

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Adsorption

• http://www.skcinc.com/abosor.html

• Passive http://www.skcinc.com/passamp.html

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Filters

• http://www.skcinc.com/prod/filters.html (good intro)

• Respirable dust and selective filtration

• http://www.skcinc.com/prod/ACyclone.html

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Calibration

• Mass of chemical determined in laboratory

)(.

)(3mvolumeS

mgMassionconcentratTWA

Page 103: Airborne Contaminants Lab

TLVoffraction Expected F

)(mg/mLimitExposureEL

ug)(DetectionofLimitLOD

VolumeSampleSV

3

FxEL

LODSV

Page 104: Airborne Contaminants Lab

Primary vs. Secondary

• Secondary– Gas meters– Rotameters

• http://www.skcinc.com/prod/frott.html

• Primary– http://www.skcinc.com/prod/sfflow.html

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Direct Reading

• Colormetric– Length of stain– Draeger

• Tubes

– +/- 25% is an oft quoted reliability– Advantages

• cheap

• fast

Page 106: Airborne Contaminants Lab

Direct Reading, electronic

• Most use Wheatstone Bridge

R R

R

Variable R

M

Page 107: Airborne Contaminants Lab

Sensor changes conductivity

• Change with temperature– LEL/UEL

• Change with gas– O2, etc.

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Calibration

• Gas supply

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NFPA

• National Fire Protection Association

• Standards setting body

• Flammable Liquid

• Combustible Liquid

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Flash Point

• The flash point is a Temperature.

• It is lowest temperature at which the liquid gives off enough vapor to form an ignitable mixture with the air above the mixture.

• Determined by closed-cup and a variety of test methods.

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Flammable Liquid

• Flammable has flash point below 100 F (37.8 C)

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Combustible Liquid

• Flash point above 100 F.

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Flammable RangeAKA Explosive Range

• LEL, Lower Explosive Limit. Minimum concentration of vapors, below which propagation of flame does not take place. The mix is too lean.

• UEL, Upper Explosive Limit. Maximum concentration of vapors, above which propagation of flame does not take place. The mix is too rich.

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LEL-UEL

• Typically expressed as vapor % of atmosphere.• For many liquids (or gases), the LEL is 6 to 12 %• Table in book lists some in 1% to 2% range• Contrast with TLV. Most TLVs are 100s or 1000s

PPM, while 1% is 10,000 PPM. So if vapor is less than TLV, much less than LEL.

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If you don’t remember anything else

• Cannot use combustion gas meters to check if low oxygen

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“Environmental” vs. Workplace

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Chemical EPA(mg/m3) OSHA (mg/m3) %Carbon 10.4 58 555% monoxideStyrene 1 425 42500%

Carbon 0.7 62 8850% disulfide

Page 118: Airborne Contaminants Lab

MSDS• Material Safety Data Sheet• Manufactures and Suppliers of “chemicals” must

supply.• Here’s a site, Safety • Always start with MSDS

– Available – Simple– One place– Don’t rely on, dimethylmercury

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Summary

• Must know what you are sampling for

• Why you are sampling

• Must calibrate

• Must keep records

• Talk to the lab.