| 近2年上海市夏季降水地球化学特征研究 |
| 摘要点击 2691 全文点击 1326 投稿时间：2009-11-02 修订日期：2009-12-11 |
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| 中文关键词 降水 化学特征 酸雨 来源 后向轨迹 上海 |
| 英文关键词 precipitation chemical character acid rain source backward trajectory Shanghai |
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| 中文摘要 |
| 在连续监测采样分析基础上运用相关性分析、主成分分析、海盐示踪法和HYSPLIT模型，分析了上海市2008年和2009年夏季降水主要成分的化学特征、来源及酸性降水的成因.近2年夏季降水中，pH平均值分别为4.72和4.68，酸雨频率分别为53.30%和63.30%；离子浓度的大小顺序为SO2-4＞NH+4＞NO-3＞Cl-＞Ca2+＞Na+＞Mg2+＞K+，其中SO2-4、NH+4、NO-3等二次组分在降水中占有较高比例，三者之和分别占降水中离子总量的55.01% 和65.97%，表明上海市大气环境中二次污染比较突出；SO2-4/NO-3的当量比分别为3.19和2.13,表明该市夏季酸性降水类型为硫酸和硝酸复合型；可溶性有机碳(DOC)含量变化范围为1.36～10.69 mg/L,平均含量为2.44 mg/L；NH+4同SO2-4( r=0.81)、NO-3( r=0.58)的相关性分别大于Ca2+同SO2-4( r=0.72)、NO-3( r=0.57)的相关性，且NH+4/Ca2+的当量比分别为1.31和2.49，说明NH+4对夏季降水酸性的中和作用大于Ca2+；夏季降水中，SO2-4、NH+4、NO-3、K+、Ca2+主要是陆源物质输入，Mg2+、Cl-两者海、陆源物质都有贡献且陆源贡献大于海源.后向轨迹分析表明上海市夏季酸性降水不仅与局地污染源有关，还与来自其西南方向的远距离污染物质输入有关. |
| 英文摘要 |
| The chemical compositions of the rainwater collected in Shanghai in Summer of 2008-2009 were investigated. The chemical character and pollutant source of rainwater were evaluated depended on HYSPLIT model, ions tracer techniques, correlation and principal component analysis. The results showed that: ① the mean pH in rain was 4.72 and 4.68; ② the frequency of acid rain was 53.30% and 63.30%, respectively, in 2008 and 2009; ③ ionic concentration was SO2-4＞NH+4＞NO-3＞Cl-＞Ca2+＞Na+＞Mg2+＞K+, in which the secondary components like SO2-4，NO- 3and NH+4 contributed significantly to total ions of rainwater and they accounted for 55.01% and 65.97% of total ions in 2008 and 2009, respectively, which indicate the severe secondary pollution in Shanghai; ④ the ratio of SO2-4 to NO-3 in Summer precipitation in 2008 and 2009 was 3.19 and 2.13, respectively, which implies sulfuric-nitrous mixed type of precipitation; ⑤ the content of DOC varied from 1.36 mg/L to 10.69 mg/L and average value was 2.44 mg/L in rainwater; ⑥ SO2-4 and NO-3 were mainly in the form of (NH4)2SO4 and NH4NO3, which showed the dominant neutralization effect of NH+4 over Ca2+ in Summer. Source identification indicated that SO2-4，NH+4，NO-3，K+ and most Ca2+ derived from anthropogenic sources, while Mg2+ and Cl- derived from both marine and non-marine but non-marine was over marine. The chemistry of precipitation in Shanghai was impacted by local pollutants and the long-and moderate-range transport by Southwest monsoon according to backward trajectory analysis. |
