Particle pollution in Beijing: features, source and secondary formation
Particle pollution in Beijing: features, source and secondary formation
复制标题
DOI：
--
复制
发表时间：
2010-05
期刊：
影响因子：
--
通讯作者：
Min Hu;Song Guo;Dingli Yue;Weiwei Hu;T. Zhu;Yuanhang Zhang;A. Wiedensohler;Y. Kondo
中科院分区：
文献类型：
--
作者：
Min Hu;Song Guo;Dingli Yue;Weiwei Hu;T. Zhu;Yuanhang Zhang;A. Wiedensohler;Y. Kondo
作为中国的首都和特大城市，北京近年来正在经历着巨大的变化。据报道，在过去的5年里，颗粒物污染是北京的主要空气污染物，在过去的5年里，大约有85%的天数是颗粒物污染(北京环境公告，2004-2008)。同时，自1998年以来，共采取了15个阶段的大气污染控制措施，并为2008年奥运会大力加强。尽管北京政府已经做出了很大努力来缓解大气颗粒物污染，但PM10水平仍然超过了目标水平，已经成为北京主要的空气污染问题。此外，区域和二次污染的存在最近也得到了承认。有机质是PM2.5质量的主要组成部分，其他城市的OC/EC比率的差异表明北京有明显的来源。一项为期两年的有机物种测量和通过受体模型进行的来源解析表明，燃煤和烹饪排放在北京是独一无二的。燃煤和机动车尾气以及各种粉尘是中国颗粒物污染的重要来源。次生有机碳是有机碳的主要组成部分，夏季占总有机碳的比例最高(45%)，冬季最低(19%)。但是，由于仍然存在一些不确定因素，二次化合物的贡献和形成机理有待于今后深入研究。作为二次气溶胶来源的新粒子形成事件在北京每年约有20%的天数出现，春季最高，夏季最低。光学闭合研究表明，Mie模式可以较好地再现北京地区的气溶胶光学性质。这项研究还强调了在烟尘上涂覆涂层在提高气溶胶吸收和散射系数方面的重要性。
As the capital of China and a major mega city, Beijing has been experiencing great changes in recent years. Particulate pollution is reported to be the major air pollutant in Beijing for about 85% of days in the last 5 years (Beijing Environmental Bulletin, 2004-2008). Meanwhile totally 15 stages control measures for air pollution have been taken since 1998, and enhanced strongly for the 2008 Olympic Games. Although great effort has been made by Beijing’s government to mitigate atmospheric particulate pollution, PM10 levels are still over the target levels and have become the major air pollution problem in Beijing. Moreover, the presence of regional and secondary pollution has been recently recognized. Organic matter constitutes a major fraction of PM2.5 mass, and the difference in OC/EC ratios from other cities indicates a distinct source in Beijing. A two-year measurement of organic species and source apportionment by receptor models showed that coal combustion and cooking emissions are unique in Beijing. Coal combustion and vehicle emissions as well as various dusts are important sources for particle pollution in China. Secondary organic carbon comprises a major fraction of OC, with the highest contribution to total OC in summer (45%) and the lowest in winter (19%). However, because some uncertainties still exist, the contributions and formation mechanisms of secondary compounds will require intense investigation in the future. New particle formation events as a source of secondary aerosol are observed on about 20% of the days each year in Beijing, with the highest frequency in spring and lowest in summer. An optical closure study showed that a Mie model can acceptably reproduce the aerosol optical properties in Beijing. This study also highlights the importance of coating on soot in enhancing the aerosol absorption and scattering coefficients.