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为了解北京大气细粒子(PM2.5)的污染水平和污染特征,在车公庄和清华园进行了连续1年、每周1次同步采样和全样品分析。2个采样点PM2.5的化学组成相似。含碳组分和水溶性离子是主要的组分,其质量浓度之和超过PM2.5的50%。有机碳、元素碳和细粒子PM2.5的季节变化一致,即冬季质量浓度最高,夏季最低。夏季NO-3的质量浓度最低且在采样过程中从特氟隆滤膜上有近50%的挥发。SO2-4不同于PM2.5的季节变化主要取决于SO2的转化率。地壳元素的质量浓度从冬季到春季大幅度上升,春季沙尘天气频是一个重要原因。
In order to understand the pollution level and pollution characteristics of Beijing’s atmospheric fine particles (PM2.5), Chegongzhuang and Tsinghua Garden were operated for 1 year in a row, with simultaneous sampling and full sample analysis once a week. The chemical composition of PM2.5 at two sampling points is similar. The carbonaceous component and the water-soluble ion are the major components, and the sum of their mass concentrations exceeds 50% of PM2.5. The seasonal changes of organic carbon, elemental carbon and PM2.5 were the same, that is, the highest concentration in winter and the lowest in summer. Summer NO-3 has the lowest mass concentration and nearly 50% volatilization from Teflon® filters during the sampling process. The seasonal change of SO2-4 from PM2.5 mainly depends on the conversion of SO2. The mass concentration of crustal elements has risen sharply from winter to spring, and the frequency of sand and dust weather in spring is an important factor.