[Pollution characterization and source apportionment of polybrominated diphenyl ethers in autumn air of Xi'an]

Air samples in gas and particle phases were collected using a high volume active sampler from August to October in 2008 at Xi'an for evaluating the pollution level of polybrominated diphenyl ethers (PBDEs). Lower brominated PBDEs and BDE-209 were analyzed via GC-MS and GC/ECD, respectively. The total concentrations (gas plus particle phases) of 12 PBDEs were ranged from 37.43 to 620.30 pg/m3, with an average of 216.28 pg/m3, while tri- to hexa-brominated congeners (Sigma11 PBDEs) ranged from 16.32 to 86. 49 pg/m3, BDE-209 ranged from 16. 34 to 576.01 pg/m3. Tri- to tetra-brominated congeners existed mainly in gas phase, tetra- to hexa-brominated congeners were predominated in particle phase, and BDE-209 was detected only in particle phase. The proportion of PBDEs in particle phase increased with bromine number. Gas-particle partition coefficient of PBDEs was well correlated with sub-cooled liquid vapor pressure, and the partitioning of PBDEs between gas and particle phases were close to equilibrium. Correlation analysis indicated that all the PBDEs have good coefficients except BDE-85. Source analysis indicated that PBDEs in the atmosphere of Xi'an were mainly from the Penta-BDE and Deca-BDE contamination.