title: Polycyclic aromatic hydrocarbons in residential dust: sources of variability.
abstract: BACKGROUND
  There is interest in using residential dust to estimate human exposure to environmental contaminants.
  
  
  OBJECTIVE
  We aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs.
  
  
  METHODS
  We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 through 2007 and during 2010) using household vacuum cleaners, and measured 12 PAHs using gas chromatography-mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability.
  
  
  RESULTS
  Median concentrations for individual PAHs ranged from 10 to 190 ng/g of dust. For each PAH, total variance was apportioned into regional variability (1-9%), intraregional between-household variability (24-48%), within-household variability over time (41-57%), and within-sample analytical variability (2-33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intraregional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration.
  
  
  CONCLUSIONS
  Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects.
authors: School of Public Health, University of California, Berkeley, Berkeley, California, USA. toddpwhitehead@berkeley.edu
authors: Todd P
authors: TP
authors: Whitehead
authors: Catherine
authors: C
authors: Metayer
authors: Myrto
authors: M
authors: Petreas
authors: Monique
authors: M
authors: Does
authors: Patricia A
authors: PA
authors: Buffler
authors: Stephen M
authors: SM
authors: Rappaport
mesh_terms: D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006798:Housing; D006801:Humans; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D011786:Quality Control; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D004391:Dust; D011084:Polycyclic Aromatic Hydrocarbons