Abstract:

In January 2008, PM_2.5 was sampled concurrently at five contrasting sites: two urban sites (the east gate of China University of Geosciences(CUGB)and the roof of a testing building within CUGB), two industrial sites (coking plant of Capital Steel Plant and a thermoelectric plant), and a background site (Ming Tombs) in Beijing, China. The concentration and spatial distribution of 19 polychlorinated biphenyls (PCBs) congeners were analyzed with isotope dilution and high resolution gas chromatography/high resolution mass spectrometry (HRGS/HRMS) based on US EPA 1668A method. PM_2.5 concentrations were in the range of 101.85-145.57 μg/m³ with mean value of 119 μg/m³, which was 83% higher than the US daily average standard(65 μg/m³), suggesting the atmospheric PM_2.5 pollution is very serious in Beijing city. ∑19PCBs and ∑TEQ concentrations varied from 7.2-16.2 pg/m3 and 8.29-17.81 fgWHO-TEQ/m³, respectively, with an average concentration of 10.9 pg/m³ and 13.58 fgWHO-TEQ/m³.PCBs levels were lower in Beijing compared to other metropolises in the world. The highest PCBs concentration was observed in industrial sites followed by urban sites and background site, incomplete combustion of fossil fuel were main sources of PCBs in Beijing. The aim of this work was to better understand the overall PCBs levels, to identify the source of PCBs in Beijing city, and to provide the scientific foundation for preventing the atmospheric persistent organic pollutants (POPs) pollution. 

Key words: PM_2.5, polychlorinated biphenyls(PCBs), isotope dilution, toxic equivalent(TEQ), Beijing city