title: Indoor residence times of semivolatile organic compounds: model estimation and field evaluation.
abstract: 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 estimated 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 among compounds. We conducted a field study after chlorpyrifos was phased out for indoor use in the United States 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 residential environment.
authors.affiliation: Department of Public Health Sciences, University of California, Davis, California 95616, USA. hmshin@ucdavis.edu
authors.forename: Hyeong-Moo
authors.initials: HM
authors.lastname: Shin
authors.forename: Thomas E
authors.initials: TE
authors.lastname: McKone
authors.forename: Nicolle S
authors.initials: NS
authors.lastname: Tulve
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Clifton
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Bennett
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D004390:Chlorpyrifos / Q000032:analysis*; D004784:Environmental Monitoring; D005430:Floors and Floorcoverings; D006798:Housing; D007306:Insecticides / Q000032:analysis*; D008956:Models, Chemical; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D007306:Insecticides; D055549:Volatile Organic Compounds; D004390:Chlorpyrifos