1) The document discusses considerations for indoor air sampling to assess vapor intrusion, including identifying contaminant sources, evaluating exposure levels and durations, and addressing confounding variables. 2) An ideal indoor air sampling method would continuously monitor contaminant and air quality parameters over time to identify vapor intrusion pathways and toxic impacts on indoor air. 3) Massachusetts screening levels for soil gas and estimated indoor air background concentrations are provided to evaluate potential indoor air impacts from vapor intrusion.

1. 1
““Assessment of Indoor Air Quality:Assessment of Indoor Air Quality:
Issues and Solutions”Issues and Solutions”
Part II – Sampling ConsiderationsPart II – Sampling Considerations
Presented By:
Peter W. Woodman, Ph.D.
President
Risk Management Incorporated
Annual LSPA/SRA Meeting
Wyndham Westborough Hotel
Westborough, M A
8th
March 2005
Risk Management Incorporated
27 Stoneymeade Way
Acton, MA 0172-5676
Phone: (978) 266-2878 www.riskmi.com

2. 2
Overall ConsiderationsOverall Considerations
 Approach should be aligned with objectives
– “You got to be careful if you don't know where you're going,
because you might not get there.” (Y. Berra)
 Consider applicability and limitations of methods
– "It isn't pollution that is hurting the environment, it's the
impurities in our air and water that are doing it." (D. Quayle)
 Attention to QA/QC is critical
– “If there is a 50-50 chance that something can go wrong,
then 9 times out of ten it will.” (P. Harvey)
Source: Dammon M. Frecker Environmental Science Services, Inc. 2001

3. 3
Fate & TransportFate & Transport
ConsiderationsConsiderations
CONTAMINATED SOIL
GROUNDWATER
KNOWN
SOURCES
HOUSEHOLD
PRODUCTS
AMBIENT/ INDOOR AIR
DRINKING WATER
VOLATILES
UNKNOWN
SOURCES
Risk Management Incorporated Phone: (978) 266-2878 www.riskmi.com

4. 4
Indoor Air Sampling ObjectivesIndoor Air Sampling Objectives
 What are we trying to determine:
– Source and nature of contamination – surface? subsurface?
– Extent and level of contamination?
– Completion of the Vapor Intrusion Pathway?
– Potential exposures in occupied spaces – residential or
commercial?
– Adverse impact and duration of exposure – acute or chronic?
– Other sources of contamination – indoors or outdoors?
– Influence of meteorological conditions and other site
variables?
Answers to these questions should guide selection of
sampling method.

5. 5
Confounding VariablesConfounding Variables
 Outdoor sources
– Nearby facilities
– Mobile sources
 Indoor sources
– Household Chemicals/Personal Care Products
– New Building Materials
– Smokers
– Heating systems

6. 6
Confounding Variables (cont.)Confounding Variables (cont.)
Site Conditions
– Ambient temperature
– Wind
– Precipitation
– Groundwater levels
– Soil oxygen content
– Building ventilation
– Occupant activities

7. 7
Sampling OptionsSampling Options
 Soil Gas, indoor or outdoor air?
 Occupied areas inside the building – basement, working
or living space - or outside?
 Grab vs. 2-, 8- or 24-hour samples – relate to duration
of potential exposures?
 How many samples, blanks, duplicates – QA/QC?
 Breathing zone or close to source?
 HVAC system operating as intended? – location of
supply & exhaust
 Occupants present?

8. 8
““Ideal” Indoor Air Sampling MethodIdeal” Indoor Air Sampling Method
Should be able to:
 Detect presence of potentially toxic vapors in air, both inside and
outside of an occupied structure, and in soil gas beneath the
building at numerous locations over time.
 Identify the potential source(s) of these vapors and determine if a
vapor intrusion pathway into the structure exists.
 Monitor contaminant concentrations on a continuous basis, along
with other indicators of indoor and outdoor air quality (e.g., CO2,
CO, humidity) and the ability of site soils to degrade contaminant
vapors in the vadose zone (e.g., O2).

9. 9
““Ideal” Indoor Air SamplingIdeal” Indoor Air Sampling
Method (cont.)Method (cont.)
 Log the data, display results graphically (e.g., Concentration
vs. Time), and allow remote access in real time for QA/QC
and full interpretation.
 Rule out confounding site variables (other indoor or outdoor
contaminant sources; meteorological conditions; preferential
migration pathways).
 Identify the toxic contaminant(s) impacting indoor air
quality via the vapor intrusion pathway; collect samples and
quantify contaminant concentrations over time (with
appropriate Detection Limits) for comparison to MADEP
Screening Levels for soil gas or Background Concentrations
for Indoor Air and/or conduct an MCP Method 3 Risk
Characterization.

10. 10
ConclusionConclusion
 Does such a sampling method exist that could collect
data to support this weight-of-evidence approach to
the assessment of risk of harm to human health via
the indoor air vapor intrusion inhalation exposure
pathway?
Risk Management Incorporated Phone: (978) 266-2878 www.riskmi.com
YES – We believe that the development and use of the
AIRXPERT System 7000 Multiport Continuous Air
Monitoring System in the field is a step in the right
direction.

11. 11
Background ScreeningBackground Screening
MADEP SOIL GAS SCREENING LEVELS FOR EVALUATION
OF INDOOR AIR IMPACTS *
 VPH/EPH/APH - measurable indoor air impacts unlikely if analyzed
fractional concentrations are below MADEP values:1,2,3
 C5-C8 Aliphatics (VPH) - 111,000 µg/m3
 C9-C12Aliphatics (VPH) - 117,000 µg/m3
 C9-C10 Aromatics (VPH) - 104,000 µg/m3
 C9-C18 Aliphatics (EPH) - 130,000 µg/m3
1
TO-1 (Tenax tubes); TO-2 (activated carbon); TO-14 (Summa™
Canisters).2
MADEP October 1997. 3
MADEP October 2002
Risk Management Incorporated Phone: (978) 266-2878 www.riskmi.com

12. 12
Background ScreeningBackground Screening
 Groundwater/surface water
 VPH/EPH/APH and target analytes - considered anthropogenic;
background concentrations assumed to be zero
 Indoor air
 VPH/EPH/APH – MADEP estimated generic indoor air
background concentrations:1
C5-C8 Aliphatics (VPH) - 85 µg/m3
C9-C12 Aliphatics (VPH) - 90 µg/m3
C9-C10 Aromatics (VPH) - 80 µg/m3
C9-C18 Aliphatics (EPH) - 100 µg/m3
1
MADEP October 2002
Risk Management Incorporated Phone: (978) 266-2878 www.riskmi.com

13. 13
Background ScreeningBackground Screening
 Indoor air
Target APH analytes1
- MADEP indoor air background concentrations:2,3
 Benzene - 21 µg/m3
 1,3-butadiene – NA
 Ethylbenzene - 10 µg/m3
 2-methylnaphthalene - 0 µg/m3
 Methyl-tert-butyl ether – 3-18 µg/m3
 Naphthalene - 5 µg/m3
 Toluene - 29 µg/m3
 Xylenes - 72 µg/m3
1
MADEP October 2002. 2
MADEP October 1992. Risk assessment Shortform.
Residential exposure scenario. Policy #WSC/ORS-142-92. 2
MADEP
Background Documentation for the Development of Numerical Standards.
April 1994.
Risk Management Incorporated Phone: (978) 266-2878 www.riskmi.com