Seasonal variation of polybrominated diphenyl ethers in PM2.5 aerosols over the East China Sea

PM2.5 aerosol samples were collected from a receptor site in the East China Sea (ECS) to explore the seasonal variation and sources of polybrominated diphenyl ethers (PBDEs). The concentrations of BDE-209 and total 11 PBDEs without BDE-209 (∑11PBDEs) were 7.1 ± 6.8 and 0.97 ± 0.52 pg m−3, respectively. A distinct seasonal variation was observed for both BDE-209 and ∑11PBDEs, that higher concentrations in winter and spring dominated by the northwesterly winds while lower concentrations in autumn and summer when the southeasterly winds prevailed, suggesting a significant role of continental outflow on the elevated concentrations of PM2.5-bound PBDEs in winter and spring. Besides, the strong dust storm could increase the load of PBDEs in continental outflow to the atmosphere over ECS. Differently, due to the absence of continental outflow in autumn and summer, the good correlations between BDE-209 and ∑11PBDEs implied a potential contribution of the low brominated PBDEs from photoproducts of BDE-209 in high temperature circumstance, while the good correlations of OC with BDE-209 and BDE-99 suggested a significant role of OC in the occurrence of PM2.5-bound PBDEs over ECS.