Personal, indoor, and outdoor VOC exposures in a probability sample of children

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 = 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 P>1>O was observed for nine of 10 VOCs, with 1,1,1-trichloroethylene (1>P>O) 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.