Passive sampler derived air concentrations of PBDEs along an urban–rural transect: Spatial and temporal trends

Passive air samplers consisting of polyurethane foam (PUF) disks housed in chambers were deployed at several sites along a ∼75 km urban–rural gradient in Toronto and analyzed for polybrominated diphenyl ethers (PBDEs). Samplers were allowed to integrate gas-phase PBDEs over three consecutive seasons starting in the summer of 2000. PBDEs were fairly uniform along the transect with air concentrations in Toronto (10–30 pg m−3) about a factor of two greater than at rural sites. Lowest concentrations were observed during the winter and probably associated with reduced inputs from indoor sources of PBDEs and to a preference for PBDEs to partition to the particle-phase at colder temperatures. The composition of PBDEs in the air samples did not differ across the transect or for the different seasons.