Latitudinal distribution patterns of OCPs and PCBs in near-surface atmospheric aerosols in the East Asian monsoon climate system: Using beryllium-7 as a reference
YANG Yong-liang;GENG Cun-zhen;LI Yong;ZHANG Gan;SHI Shuang-xin;ZHU Xiao-hua;JIAO Xing-chun;TAN Ke-yan;YU Han-qing;National Research Center of Geoanalysis, Key Laboratory of Ecological Geochemistry,MLR;College of Chemistry, Chemical and Environmental Engineering, Qingdao University;Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences;State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry, Chinese Academy of Sciences;National Research Center for Environmental Analysis and Measurements, Dioxins Laboratory of the National Research Center for Environment Analysis and Measurement;
Using the cosmogenic nuclide7Be as a reference, here we show that the atmospheric circulation in East Asian monsoon climate system(EAMCS) can affect the latitudinal distributions of POPs. Beryllium-7(7Be) concentrations in near-surface atmospheric aerosols at sampling frequency of 3 d per week for one year in Beijing, Qingdao, and Guangzhou are summarized. Simultaneous measurements of7Be, organochlorine pesticides(OCPs), and polychlorinated biphenyls(PCBs) at five different latitude cities in EAMCS were conducted during the seasonal transition period of spring and autumn. We observed that the latitudinal distribution of the annual average 7Be concentrations follows a normal distribution pattern, with the maximum occurring at ~40°N. The instantaneous observation of7Be at different latitude sampling sites in EAMCS also showed a normal distribution pattern, but with the maximum at 30°N in spring and autumn. The maximum concentrations of OCPs and PCBs in near-surface aerosols occurred at different latitude showed a similar pattern as that of7Be, i.e. with the maximum at 30°N. The abundance of PCB-28 in vapor phase increased with latitude but nearly unchanged with latitude in aerosols. PCB-180, which has low evaporation tendency, in aerosols showed enrichment at 36°N, while PCB-180 in vapor phase appeared to be nearly unchanged with latitude. Our results suggest a latitude-focused accumulation mechanism for POP compounds with lower volatile tendency in the atmosphere in EAMCS. Using cosmogenic nuclide7Be as a reference, the conclusion that atmospheric circulation in EAMCS may influence the latitudinal distribution of POPs can be made.