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Indoor Residence Times of Semivolatile Organic Compounds: Model Estimation and Field Evaluation
Citation:
Shin, H., T. McKone, N. Tulve, M. Clifton, AND D. Bennett. Indoor Residence Times of Semivolatile Organic Compounds: Model Estimation and Field Evaluation. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 47(2):859-867, (2013).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL′s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA′s mission to protect human health and the environment. HEASD′s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA′s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Indoor residence times of semivolatile organic compounds (SVOCs) are a major and mostly unavailable input for residential exposure assessment. We calculated residence times for a suite of SVOCs using a fugacity model applied to residential environments. Residence times depend on both the mass distribution of the compound between the “mobile phase” (air and dust particles settled on the carpet) and the “non-mobile phase” (carpet fibers and pad) and the removal rates resulting from air exchange and cleaning. We developed dust removal rates from cleaning processes using an indoor-particle mass-balance model. Chemical properties determine both the mass distribution and relative importance of the two removal pathways, resulting in different residence times between compounds. We conducted a field study after chlorpyrifos was phased out for indoor use in the U.S. in 2001 to determine the decreases in chlorpyrifos air concentrations over a one year period. A measured average decrease of 18% in chlorpyrifos air concentrations indicates the residence time of chlorpyrifos is expected to be 6.9 years and compares well with model predictions. The estimates from this study provide the opportunity to make more reliable estimates of SVOCs exposure in the indoor environment.
URLs/Downloads:
HEASD - 12-028 TULVE SHIN ET AL RESIDENCE TIME V1 CLEAN COPY 7272012.PDF (PDF, NA pp, 305.726 KB, about PDF)Environmental Science and Technology
