Levels, compositions, and gas-particle partitioning of polybrominated diphenyl ethers and dechlorane plus in air in a Chinese northeastern city

Air samples were collected using a HiVol air sampler for 24 hours every week from September 2008 to August 2009 in the city of Dalian, a typical coast city in Northeast China. 12 polybrominated diphenyl ethers (PBDEs) congeners (BDE-17, -28, -47, -66, -85, -99, -100, -138, -153, -154, -183 and -209) and Dechlorane Plus (DP) were measured and analyzed. Annual arithmetic mean concentrations of ∑ ₁₂PBDEs (gas+particle phase) and DP (Particle phase) in air samples were 104±95pgm ^-3 and 3±6pgm ^-3, respectively. BDE-209 was the dominating congener in all seasons with the contribution of 56±21% of ∑ ₁₂PBDEs, followed by BDE-28, -47 and -99. The mean fractional abundance of the syn-DP isomer (f _syn) in all samples was 0.31±0.14, lower than the value reported for technical DP mixture produced in China (f _syn=0.4), indicating depletion of syn-DP in Chinese air. A year monitoring of PBDE in air produced a large dataset that provided a gas-particle partitioning analysis based on a wide temperature range and also individual PBDE congeners. The values of the portion of PBDEs in particle phase to the whole PBDEs in air had a general trend that became higher with the increasing number of bromine atoms at the same temperature and with decreasing temperature for the same congener. The result of PBDEs gas-particle partitioning analysis indicated that PBDEs in gas and particle phases were closer to equilibrium at higher temperature periods. For the first time, the K _OA-based absorption model was evaluated for individual PBDE congeners. The results showed that, the model is more suitable for predicting low brominated congeners than high brominated ones, and the accuracy of model predictions decreases along with decrease of temperatures for individual PBDE congeners.