Polychlorinated biphenyls(PCBs) are stable in the environment,undergo long-range atmospheric transport,and possess the ability to bioaccumulate through the food chain which can impose a serious threat to human health and the environment.Atmosphere is the major pathway for PCBs to transport and redistribute in the environment.In order to know levels and patterns of PCBs in background air in China,high-volume air samples were collected at 11 background sites from November 2007 to February 2008.PCBs were extracted from samples by accelerated solvent extraction(ASE) and then purified by acid silica column and fluid management systems(FMS).Confirmation and quantitative analysis were performed by HRGC-HRMS using voltage selective ion record mode.Total concentrations of dioxin-like PCBs in background air ranged from 348.8 fg/m3 to 1 768.3 fg/m3(0.7-7.4 fg TEQ/m3),and total concentrations of indicator PCBs were from 9.0 pg/m3 up to 85.2 pg/m3,which were both lower than the concentrations of most other regions and countries.
