A Compilation of Statistics for VOCs from Post‐1990 Indoor Air Concentration Studies in North American Residences Unaffected by Subsurface Vapor Intrusion

Abstract

This paper provides a summary of a number of indoor air quality studies reporting concentrations of volatile organic compounds (VOCs) in indoor air samples collected from residential properties in North America and provides average values for certain statistics (percentiles, detection frequency, maximum). This compilation includes several VOCs that are commonly assessed in studies of subsurface vapor intrusion to indoor air, but may also be attributable to consumer products, building materials, or even outdoor air (ambient) sources, specifically benzene, carbon tetrachloride, chloroform, 1,1-dichloroethane, 1,1-dichloroethene, 1,2-dichloroethane, cis and trans-1,2-dichloroethene, ethylbenzene, methyl tert-butyl ether, methylene chloride, tetrachloroethene, trichloroethene, toluene, trichloro-1,2,2-trifluoroethane, 1,1,1-trichloroethane, vinyl chloride, and meta, para, and ortho-xylene. In studies spanning 1990 through 2005, eleven of these compounds were detected in more than 50% of samples collected, and for several compounds (benzene, carbon tetrachloride, chloroform, ethylbenzene, and tetrachloroethene) the lower and upper quintiles of the indoor air concentrations are within the range of typical risk-based target levels. These summary statistics may help interpret data collected during a vapor intrusion investigation and communicate the findings of indoor air quality studies to building occupants and other stakeholders. Similar studies have been published in the past, but there has been a gradual change in indoor air quality over time and a large amount of new data has been collected, so this paper provides more relevant information for current use than previous compilations.

Hazard assessment of chemical air contaminants measured in residences

“…Our results are similar to those identified by the reviews done by Dawson and McAlary (2009), Koistinen et al(2008), and Loh et al(2007) with some distinct differences. Loh et al(2007) identified a similar subset of high priority VOC and SVOC chemical air pollutants using a combination of measurements and modeling.…”

“…Our review identified a similar set of VOC and SVOC priority pollutants with the addition of acrolein, which was not included in their study. Dawson and McAlary (2009) identified benzene as a having an elevated cancer risks in most homes by comparing concentrations of a subset of 10 VOCs to available standards. Koistinen et al(2008) identified 5 priority pollutants in European homes, formaldehyde, CO, NO2, benzene, We also compared our results to an older review done by Brown et al(1994) to look at changes in concentrations over time.…”

Vapor intrusion attenuation factors relative to subslab and source, reconsidered in light of background data

“…Figures 4a and b were prepared from the U.S. EPA VI database, selecting only those data meeting the criterion of falling below the 500 μg/m 3 cutoff. These data are compared with other published data from non-VI indoor air studies [27-31]. The results from Dawson and MacAlary [27] actually summarized some of the other datasets shown, but the individual results are given just to provide a sense that the summary captured well many other study results.…”

Use of On-Site GC/MS Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs

“…Indoor sources of VOCs are ubiquitous, resulting in detectable concentrations in indoor air that are often above regulatory screening levels. For example, background concentrations of TCE range from 0.3 to 1.6 µg/m 3 in houses unaffected by vapor intrusion (50 th to 95 th percentile values; Dawson and McAlary, 2009), concentrations that are the same level when compared to a residential 10 -6 risk limit of 0.43 µg/m 3 (USEPA, 2013). Background concentrations of TCE, benzene, and several other VOCs also commonly exceed regulatory screening levels (USEPA, 2011a).…”