Black carbon in the atmospheric dust of Beijing City and its north area
北京及其北部地区大气降尘中的黑碳含量特征

The black carbon (BC) is widely concerned for its adverse environmental effects. In this study, atmospheric dust samples were collected from ten sites in Beijing and surrounding areas, and the BC concentrations were analyzed. The monthly average BC concentrations of dust samples ranged from 1.21 mg·g-1 to 50.10 mg·g-1, with the lowest and highest BC concentrations recorded as 3.32 mg·g-1 in May and 10.40 mg·g-1 in September, respectively. Generally, BC concentrations of dust was lower in winter and spring, which might be resulted from the "dilution" of abundant local topsoil and sand imported in winter and spring. Annual BC flux of dust among all sites ranged from 761 mg·m-2·a-1 (Fengning) to 1659 mg·m-2·a-1 (Beijing). Seasonal dust BC flux distribution patterns were more uniform in urban area because of the temporal consistency of BC sources. Though urban dust had higher BC concentrations than that of most rural sites, frequent dust weather might also bring high dust BC flux to some outfield areas.