[Characteristics and sources of trace elements in ambient PM2.5 in Beijing].
[Characteristics and sources of trace elements in ambient PM2.5 in Beijing].
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发表时间：
2003-11
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通讯作者：
Fumo Yang;K. He;Yong-liang Ma;Xu Chen;S. Cadle;C. Tai;P. Mulawa
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作者：
Fumo Yang;K. He;Yong-liang Ma;Xu Chen;S. Cadle;C. Tai;P. Mulawa
为了解北京环境空气中PM2.5（空气动力学直径小于2.5微米的颗粒物）浓度和成分中微量元素的浓度水平和来源，在车公庄和清华园连续一年每周同时采集样品。微量元素表现出类似的显着每周变化。最强的周变化发生在冬季，连续两周高达 1.6 倍。微量元素没有发现明显的季节性模式，只是冬季的平均浓度要高得多。微量元素EF在春季最低，可能是由于沙尘暴频繁导致人为源贡献减少、土壤扬尘贡献增加所致。环境中Se、Br和Pb的浓度比北京地壳土壤中的预期浓度高出约1000-8000倍。 PM2.5中硒含量最高，反映了北京燃煤细颗粒物的特征。铅的年平均浓度为0.31微克·米-3，虽然没有超过世界卫生组织的年标准，但与洛杉矶和布里斯班的测量值相比，仍处于很高的水平。 Pb与Br、Se的对比分析表明，燃煤可能是PM2.5中除汽车尾气之外Pb的另一个主要来源。
To understand concentration levels and sources of trace elements in PM2.5(particulate matter with aerodynamic diameters less than 2.5 microns) concentration and composition in the ambient air of Beijing, weekly samples were simultaneously collected for one year in Chegongzhuang and Qinghuayuan. Trace elements exhibited similar significant weekly variations. The strongest weekly shift occurred in winter, which reached as high as a factor of 1.6 for two consecutive weeks. No obvious seasonal pattern was found for trace elements except for that their average concentrations were much higher in winter. The EFs of trace elements were lowest in spring, probably due to frequent dust storms resulting in reduced contribution of anthropogenic sources and increased contribution of soil dust. The ambient concentrations of Se, Br, and Pb were about 1000-8000 times higher than those expected from the crustal soil in Beijing. Se was most enriched in PM2.5, reflecting the characteristics of fine particles from coal burning in Beijing. The annual mean concentration of Pb of 0.31 microgram.m-3 did not exceeded the WHO annual standard, but was at very high level compared to those measured in Los Angles and Brisbane. Comparison analysis of Pb with Br and Se shows that coal burning is probably another major source of Pb in PM2.5 other than vehicle emission.