title: Determining source strength of semivolatile organic compounds using measured concentrations in indoor dust.
abstract: Consumer products and building materials emit a number of semivolatile organic compounds (SVOCs) in the indoor environment. Because indoor SVOCs accumulate in dust, we explore the use of dust to determine source strength and report here on analysis of dust samples collected in 30 US homes for six phthalates, four personal care product ingredients, and five flame retardants. We then use a fugacity-based indoor mass balance model to estimate the whole-house emission rates of SVOCs that would account for the measured dust concentrations. Di-2-ethylhexyl phthalate (DEHP) and di-iso-nonyl phthalate (DiNP) were the most abundant compounds in these dust samples. On the other hand, the estimated emission rate of diethyl phthalate is the largest among phthalates, although its dust concentration is over two orders of magnitude smaller than DEHP and DiNP. The magnitude of the estimated emission rate that corresponds to the measured dust concentration is found to be inversely correlated with the vapor pressure of the compound, indicating that dust concentrations alone cannot be used to determine which compounds have the greatest emission rates. The combined dust-assay modeling approach shows promise for estimating indoor emission rates for SVOCs.
  
  
  CONCLUSIONS
  The combined dust-assay modeling approach in this study can be used to predict the source strength of indoor released compounds, integrating emissions from consumer products, building materials, and other home furnishings. Our findings show that estimated emission rates are closely related to not only the level of compounds on dust, but also the vapor pressure of the compound. Thus, a fugacity-based indoor mass balance model and measured dust concentrations can be used to estimate the whole-house emission rates from all sources in actual indoor settings, when individual sources of emissions are unknown.
authors.affiliation: Department of Public Health Sciences, University of California, Davis, CA, USA.
authors.forename: H-M
authors.initials: HM
authors.lastname: Shin
authors.forename: T E
authors.initials: TE
authors.lastname: McKone
authors.forename: M G
authors.initials: MG
authors.lastname: Nishioka
authors.forename: M D
authors.initials: MD
authors.lastname: Fallin
authors.forename: L A
authors.initials: LA
authors.lastname: Croen
authors.forename: I
authors.initials: I
authors.lastname: Hertz-Picciotto
authors.forename: C J
authors.initials: CJ
authors.lastname: Newschaffer
authors.forename: D H
authors.initials: DH
authors.lastname: Bennett
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D002140:California; D002675:Child, Preschool; D004391:Dust / Q000032:analysis*; D005260:Female; D006801:Humans; D008396:Maryland; D008956:Models, Chemical; D010414:Pennsylvania; D011247:Pregnancy; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D004391:Dust; D055549:Volatile Organic Compounds
keywords: Dust; Emission rates; Flame retardants; Modeling; Personal care products; Phthalates