Personal, Indoor, and Outdoor VOC Exposures in a Probability Sample of Children

Abstract

As part of the Minnesota Children's Pesticide Exposure Study we measured volatile organic compound (VOC) concentrations in a probability sample of households with children. The 6-day average concentrations for 10 common VOCs were obtained in urban and nonurban residences twice during this multiphase study: screening-phase indoor measurements were collected in 284 households, and in the intensive-phase matched outdoor (O), indoor (I), and personal (P) measurements were collected in a subset (N ¼ 72) of the screened households. Screening-phase households with smokers had significantly higher concentrations of benzene and styrene compared to nonsmoking households; households with an attached garage had significantly higher levels of benzene, chloroform, styrene, and m/p-and o-xylene compared to households without an attached garage; and nonurban residences, which had a greater prevalence of smokers and attached garages, had significantly higher 1,1,1-trichloroethane, styrene, and toluene and significantly lower tetrachloroethylene concentrations compared to urban households. The screening-phase weighted distributions estimate the mean and variability in indoor VOC concentrations for more than 45,000 households with children in the census tracts sampled. Overall, median indoor concentrations of most VOCs measured in this study were similar to or lower than indoor levels measured previously in the United States. Intensive-phase outdoor VOC concentrations were generally lower than other major metropolitan areas, but urban concentrations were significantly higher than nonurban concentrations for all compounds except 1,1,1-trichloroethylene. A consistent pattern of P4I4O was observed for nine of 10 VOCs, with 1,1,1-trichloroethylene (I4P4O) being the only exception to this pattern. For most children, the indoor at-home microevironment was strongly associated with personal exposure after controlling for important covariates, but the ratio of median to upper bound exposures was smaller than that observed in studies of adults. There are relatively little data on VOC exposures in children, so these results are useful for estimating the central tendency and distribution of VOC exposures in locations where children spend a majority of their time.

Multiple comparisons of organic, microbial, and fine particulate pollutants in typical indoor environments: Diurnal and seasonal variations

“…Although KG, PS, and WP were located in the same region, the biggest differences between the I/O ratios of KG/PS and WP show us that the major sources of VOCs in KG and PS originated from indoor sources. It was found that children were exposed to VOCs in the houses more than outside, probably due to the house-originated sources (Adgate et al, 2004). The I/O ratios of H1 and H2, both located near traffic sources, were lower than those calculated for KG and PS.…”

Defining Urban and Rural Areas in U.S. Epidemiologic Studies

“…3 Environmental epidemiologic studies concerned with pollution or other exposures within a rural or urban environment continue to be conducted. [4][5][6][7] In addition, in the United States, the rural health disparity has been a recent focus of attention and made a priority for improvement, 8 while urban health is an emerging discipline. 9 Concomitantly with these areas of research interest and activity, it is likely that Bexposure[ to urban and rural living will be increasingly studied.…”

Evaluating methods for predicting indoor residential volatile organic compound concentration distributions

“…For example, several homes in the BEAM study had attached garages, and it has been shown that this feature may affect indoor residential concentrations for certain compounds (Wallace, 1991;Gordon et al, 1999;Graham et al, 2004;Adgate et al, 2004b;Dodson et al, 2008). The influence of an attached garage was explored by calculating the three source indicators (namely, source strength, I-O difference and I/O ratio) for only those homes in the BEAM study without an attached garage, and then by comparing the across-study prediction results using these homes with the predictions based on all of the BEAM homes.…”

“…Indoor air concentrations of a number of volatile organic compounds (VOCs) are often higher than outdoor concentrations (Clayton et al, 1999;Wallace, 2001;Adgate et al, 2004b;Sexton et al, 2004b). This, in combination with the significant amount of time people spend indoors, results in indoor exposures having a greater impact on total exposure and potential health effects than outdoor air concentrations (Adgate et al, 2004a;Sexton et al, 2004a;Sax et al, 2006).…”