1. Jay Peters Gina M. Plantz Richard J. Rago
Implications of indoor air background concentrations on health risks in buildings
Jay Peters
Gina M. Plantz
Richard J. Rago

2. Major sources of VOCs in indoor air (IA): homes, offices, and schools
Consumer products
Cleaners; personal, hobby, and auto care products; furniture and furnishings
Building materials
Flooring, construction adhesives, paint, stain
Heating systems
Fossil fuel burning
Outdoor air
Industrial and vehicular emissions
Environmental contamination
Vapor intrusion

3. Major sources of VOCs in indoor air: homes, offices, and schools
Consumer products
Cleaners; personal, hobby, and auto care products; furniture and furnishings
Building materials
Flooring, construction adhesives, paint, stain
Heating systems
Fossil fuel burning
Outdoor air
Industrial and vehicular emissions
Environmental contamination
Vapor intrusion
Indoor air background
Is there a way we can get this red box to animate around the previous slide?

4. Indoor air background Recognized in environmental regulations
“Indoor air concentrations resulting from sources other than vapor intrusion (i.e., ambient air and indoor sources) are commonly referred to as “background.” (EPA, 2011)
“Background IA sources can be broken down into several categories … household activities, consumer products, building materials and furnishings, ambient air pollution.” (NJDEP, VITG 2013)
EPA provides guidance on addressing background conditions in Superfund cleanups (Role of Background in the CERCLA Cleanup Program, OSWER Directive No P, April 26, 2002)
But … health risk associated with indoor air background and implications on risk management for environmental contamination not well established

5. Identified background indoor air concentrations of VOCs
Approach
Identified studies that examined indoor air quality from background sources
Identified background indoor air concentrations of VOCs .
Characterized health risks associated with background indoor air quality
Evaluated health risks in the context of common environmental risk management guidelines

6. Residential indoor air background studies
Considered three major studies:
2,898 samples; compiles data from 15 studies ( )
“Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences (1990–2005): A Compilation of Statistics for Assessing Vapor Intrusion, EPA 530-R , June 2011”
200 indoor air background samples in Los Angeles, CA, and Houston, TX
“Relationships of Indoor, Outdoor, and Personal Air (RIOPA),” Weisel et al, The Health Effects Institute, November 2005
100 indoor air background samples in Montana
“Typical Indoor Air Concentrations of Volatile Organic Compounds in Non-Smoking Montana Residences Not Impacted by Vapor Intrusion,” Montana Department of Environmental Quality, August 2012

7. Non-residential indoor air background studies
Offices
EPA Building Assessment Survey and Evaluation (BASE) Study (1999)
California Health Buildings Study (Daisey et al, 1994)
Haley & Aldrich: Rago et al ( ); manuscript in preparation
Jay to add sample numbers to these slides
Schools
Adgate et al (2004)
Haley & Aldrich: Rago et al ( ); manuscript in preparation

8. Background concentrations
Focused on:
VOCs commonly analyzed and detected among IAQ studies
VOCs of potential concern for environmental contamination
Three main groups of VOCs:
Benzene, ethylbenzene, toluene, xylene (BTEX)
Chlorinated VOCs: tetrachloroethylene (PCE), trichloroethylene (TCE), 1,2-dichloroethane (DCA), vinyl chloride (VC), chloroform, carbon tetrachloride
Petroleum-related: naphthalene, aliphatic and aromatic hydrocarbons
Background defined as a range of concentrations: 50th and 90th percentile values of background data set .

10. Characterizing health risks
Risk is a function of
Air concentration
Exposure time (hours/day) and frequency (days/year)
Toxicity
Toxicity values derived by USEPA
Cancer unit risk factor (URF) – non-threshold effects; used to derive incremental lifetime cancer risk (ILCR)
Reference concentration (RfC) – threshold effects; used to derive hazard index

11. Risk management levels
Risk management: cancer risk
Probability of carcinogenic response in excess of background cancer risk
1 in 1,000,000 (1x10-6) x 1 in 10,000 (1x10-4)
Many states: 1x10-6 to 1x10-5
Risk management: non-cancer hazard
No increased risk of adverse health effects
Hazard index (HI): 1
Screening levels are set at the lowest risk management thresholds, to gauge whether a chemical requires further evaluation
Risks are managed as cumulative risk among all chemicals

12. Inset box “Hazard rank = background / screening level’

15. INSERT GRAPHIC HERE: COMPARE RES, OFFICE, SCHOOL BACKGROUND FOR THE 7 COCs
Cancer Risks
Cumulative Cancer Risk:
2x10-4 (90th PCTL)
7x10-5 (50th PCTL)
Edit figure to state ‘cancer risk’ (not ‘risk rank ranges’). Add inset box with cumulative risks and add lines to show risk management ranges

16. HI = 1

17. Summary of indoor air background risks
ILCR and maximum hazard index (HI) for 50th and 90th percentile background indoor air
Residences: ELCR = 7x10-5 to 2x10-4 and HI = 1 to 4
Schools: ELCR = 2x10-6 to 3x10-6 and HI = 0.2 to 0.3
Offices: ELCR = 2x10-6 to 5x10-6 and HI = 0.1 to 0.4
Background risk estimates for residences 1-2 order of magnitudes higher than for schools and offices

18. Conclusions
Residential background indoor air is associated with cumulative risks well above the threshold risk management levels used by most regulatory agencies
Screening levels for indoor air are below or within the ranges for normal residential indoor air background
Decisions about managing environmental contamination from vapor intrusion focus on levels well within or below background

19. Thank You! Jay Peters Haley & Aldrich, Inc. Gina Plantz Richard Rago
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Gina Plantz
Haley & Aldrich, Inc.
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Richard Rago
Haley & Aldrich, Inc.
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