Analytical Methods for Air and Vapor

Sampling

Andy Rezendes

Alpha Analytical Labs

Andy Rezendes, Alpha Analytical, Inc.

October 11, 2011

EBC SubSlab Mitigation

Systems for Vapor Intrusion

Analytical Methods for Air and Vapor

Sampling

www.alphalab.com

Synopsis:

♦ General Overview of Air Analytical Methods

♦ Sampling Soil Vapor and Ambient Air w/ Canisters

♦ Regional Sampling Procedures for VI Investigations-

♦ MA, CT, NH, ME

♦ Your questions…

Analytical Methods for Air and Vapor Sampling

www.alphalab.com

Principle of Air Sampling

• Air sampling is conducted by creating a controlled pressure differential via mechanical means to

allow air flow into or through a collection device

Whole air sample

collect air sample in container, return to lab

Sorbent sample collect compounds of concern using solid or liquid media, return to lab

www.alphalab.com

Air Analysis Methodology

EPA Compendium of Methods (TO methods)

Source test methods-40 CFR part 60 app. A

NIOSH / OSHA methods-designed for PELs

IP methods (indoor air)

MA DEP APH method (Air-phase Petroleum

Hydrocarbons)

www.alphalab.com

Air Sampling Equipment

Canisters (FSL and SUMMA),

Tedlar bags, tubes, or badges for

VOCs

MCE or PVC cartridges for dust

and inorganics

PUF cartridges for semivolatile

organics

www.alphalab.com

grab filter F.C. w/ soil vapor

config. ambient air F.C.

2.7 Liter

• Flow controller configurations

• Canisters

• does size matter?

Air Sampling Equipment for

Canister Sampling

6.0 Liter 1.0 Liter

Smaller sizes are being

produced (i.e. 100 mL)

www.alphalab.com

• Correct configuration of flow controllers-soil vapor or ambient?

• Canister vacuum should be at 30 in.-check w/ flow controller or vacuum gauge

• Chain of custody-record can ID and flow controller serial # for your benefit!!

• Record start-stop vacuum readings

Canister Sampling Documentation

www.alphalab.com

Canister Sampling Documentation

COC Review

www.alphalab.com

• Typically composite or time weighted average (TWA)

• Duration should reflect the exposure scenario

• Grab sample only if odors are an issue

• Must be sampled through 2 micron particulate filter

• Field duplicates obtained by co-locating canisters

General Principles

Ambient Air Sampling

www.alphalab.com

• Maximum flowrate = 200 mL/min

• Use Teflon or polypropylene tubing to connect to soil gas

probe, check w/ lab for size (typically ¼” OD)

• Must be sampled through 2 micron particulate filter

!!!!

• Field duplicate sampling an issue; tee-off co-locate?

• Provide screening data on COC if available

General Principles

Soil Vapor Sampling

www.alphalab.com

• Ambient air samples –should have some vacuum left in canister (i.e. 5 in. Hg) – more critical if not

• Soil vapor samples –should have some vacuum left in canister (i.e. 5 in. Hg) – less critical if not

• Grab samples – final vacuum not critical, can go to 0 in. Hg

• Greater than 15 in. Hg – may be a need for dilution

Post – Sampling, when am I done?

www.alphalab.com

Compound Typical

Concentration

Chloromethane 0.5 ppbV / 1.03 ug/m3

CH4 + Cl2 UV

CH3Cl + HCl

Dichlorodifluoromethane

0.5 ppbV / 2.5 ug/m3

Petroleum / Combustion-related

compounds

Benzene = 0.1 ppbV / 0.32 ug/m3

Carbon Tetrachloride (10-6 = 0.16 ug/m3)

0.1 ppbV / 0.63 ug/m3

Atmospheric Background of VOCs

www.alphalab.com

Subslab Mitigation Systems and

PVC Cement

Ingredient Percent

Acetone 10-20

2-Butanone 0-5

Cylcohexanone 10-16

Tetrahydrofuran 50-60

Polyvinylchloride (PVC) 12-18

Regional Sampling Procedures MA MCP, CT, NH, ME

www.alphalab.com

MADEP Vapor Intrusion Guidance WSC# (DRAFT)

Main document

Assesment Mitigation Regulator Framework

Communication & Public Involvement Obtaining Access

•Appendix 1 –Threshold Values

•Residential – TVr

•Industrial/Commercial – TVi/c

•Appendix 2 –Soil Gas Screening Values – currenlty reserved (0.05 attenuation factor)

•Appendix 3 –Detailed Sampling Procedures

•Appendix 4 – Common GW and Soil Remidiation Approaches-reserved

•Appendix 5- Guidance on the Design, Installation, Operation, and Monitoring of Sub-

Slab Depressurization Systems

•Appendix 6 - References for Other Active Mitigation Systems

•Appendix 7 - Mitigation System Check List

•Appendix 8 -Use of Activity and Use Limitations (AULs) to Address Future Buildings

in Areas of Potential Vapor Intrusion

www.alphalab.com

Parameter Most Conservative Conditions Least Conservative

Conditions

Season Late winter/early spring Summer

Temperature Indoor 10oF > than outdoors Indoor temp < outdoor temp.

Wind Steady, > ~5 mph Calm

Soil Saturated with rain Dry

Doors/Windows Closed Open

Heating System Operating Off

MADEP Guidance-Sampling Indoor

Air

When to sample (table 2-3)

Sampling composite times (recommended) –

Commercial – 8 hr

Residential – 24 hr (minimum of 4 hr)

www.alphalab.com

Outdoor air sample recommended

Can limit investigation to COCs, refer to MassDEP Risk

Characterization Guidance (sect. 2)

Should be sampled simultaneously or at a similar time as

subslab/soil vapor samples

Other collection devices allowed in App. 3 (vials, bags,

passive monitors, tubes), no MCP methodology for these

devices

MADEP Guidance-Sampling

Indoor Air

www.alphalab.com

Currently main document not consistent w/ appendices

Should not be sampled “at too high a rate”, will most likely

be updated to 200 mL/min

Should be sampled simultaneously or at a similar time as

indoor air samples

MADEP Guidance-Sampling

Subslab/Soil Vapor

www.alphalab.com

• “Hybrid method” of TO-15 and VPH methods

• Method has been finalized (December 2009)

• Labs will not be subtracting out “non-petroleum

hydrocarbons” unless requested

• 2-Methylnaphthalene dropped from TAL

MADEP APH

(Air-phase Petroleum Hydrocarbons)-Update

www.alphalab.com

CAM Methods for TO-15 and

APH

• Question E – APH & TO-15 Methods – was the complete TAL reported for each method?

• Lab reporting requirements – Sample results

– Method Blank

– LCS

– Matrix duplicate

– Internal standard performance

– Media certification results

– Flow controller calibration results

– Vacuum of canister at receipt in lab

www.alphalab.com

CAM Methods for TO-15

and APH

• Data User (that’s you) Reporting Requirements

– Serial # of canister for each sample ID

– Serial # of flow controller for each sample ID

– Sample duration

www.alphalab.com

• Screening values for residential and commercial sites

• Specific target analyte list and RLs (Table 1)

• Soil gas sampling – maximum flowrate of 200 mL/min

• Ambient air sampling – 8 hr. or 24 hr. composite (commercial / residential)

• Living space closest to VI pathway

NHDES Vapor Intrusion Guidance Manual

www.alphalab.com

• Does not address sampling

• Has specific target analyte list and limits for soil vapor, indoor air

– Residential

– Commercial

• References EPA Vapor Intrusion Guidance

• Currently working on new guidance

CT & RI RSR Criteria

www.alphalab.com

• New guidance out, January 2010 (sampling guidance is draft)

• Has screening values for following:

– Residential – chronic & subchronic (7 yr), both single and multi-component

– Commercial – chronic & subchronic (7 yr), both single and multi-component

• Indoor air sampling duration: 24 hr. residential, 8 hr. commercial

• Soil vapor samples – 30 minute duration

• Has adopted APH method for petroleum-related sites

Maine Vapor Intrusion Guidance