This study reports concentrations of BDEs 47, 99, 100, 153, and 154 in outdoor air [median sigmaPBDE (sum of BDEs 47, 99, 100, 153, and 154) = 18 pg m(-3)] in air from a range of office and home indoor microenvironments (median sigmaPBDE = 762 pg m(-3)) and vegan and omnivorous duplicate diet samples (median sigmaPBDE = 154 and 181 pg g(-1) dryweightforvegan and omnivorous diets, respectively). Median daily human exposure to sigmaPBDE via inhalation is 6.9 ng/person and 90.5 ng/person via diet but the relative significance of these pathways may vary considerably between individuals. Median concentrations in indoor air were higher in workplace (sigmaPBDE = 1082 pg m(-3)) than in domestic (sigmaPBDE = 128 pg m(-3)) microenvironments, and substantial differences in concentrations in air from different rooms in the same office building were found. When data from the only mechanically ventilated room was excluded, a significant positive correlation (p < 0.001) was observed between PBDE concentrations and both the number of electrical appliances and polyurethane foam-containing chairs. Concentrations of sigmaPBDE and BDEs 47 and 99 were significantly higher (p < 0.1) in omnivorous diet samples than in vegan diet samples, implying that while plant-based foods contribute appreciably, higher exposure occurs via ingestion of animal-based comestibles.