Emissions of polybrominated diphenyl ethers (PBDEs) in Zurich, Switzerland, determined by a combination of measurements and modeling

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants but they are of concern and are currently being phased-out because of their environmentally hazardous properties and their potential to cause adverse health effects. We analyzed PBDEs in Zurich, Switzerland, and applied a multi-media environmental fate model to back-calculate the rate of PBDE emission to air. PBDE concentrations in ambient air were measured in summer 2010 and winter 2011 in the city center of Zurich. Concentrations were higher in summer (sum PBDEs 118-591 pg m−3) than in winter (sum PBDEs 17-151 pg m−3), and are on the upper end of concentrations reported in literature for urban sites with no point sources of PBDEs. The emissions derived from our measurements (summer: 53-165 μg capita−1 d−1, winter: 25-112 μg capita−1 d−1) and extrapolated to annual emissions for Switzerland (114-406 kg a−1) lie in the middle of ranges reported on the basis of substance flow analyses and emission inventories. The difference between summer and winter emissions is small compared to the difference that would be expected from the temperature dependence of PBDE vapor pressure, which would be consistent with emissions occurring to a large extent from flame-proofed materials located indoors under nearly constant temperature conditions and/or emissions to air occurring by suspension of particles containing PBDEs. Compared to previous studies in Switzerland, concentrations and emissions of PBDEs appear to have increased during the last five years with an increasing contribution of decabromodiphenyl ether, despite the addition of PBDEs to national and international regulations.