Size distribution of water-soluble inorganic ions in urban aerosols in Shanghai
Size distribution of water-soluble inorganic ions in urban aerosols in Shanghai
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DOI：
10.5094/apr.2014.073
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发表时间：
2014-10
影响因子：
4.5
通讯作者：
Ye Tao;Zi Yin;X. Ye;Zhen Ma;Jianmin Chen
中科院分区：
文献类型：
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作者：
Ye Tao;Zi Yin;X. Ye;Zhen Ma;Jianmin Chen
摘要研究了上海市城市气溶胶中水溶性无机组分的粒径分布。采用离子色谱法对2012年4 - 5月8级层叠采样器采集的气溶胶样品进行了分析。2.1 μm以下粗粒颗粒的离子质量浓度为so4 - > no3 - ~ nh4 + > ca2 + >Na + ~Cl - >K + >Mg 2+ >F−，3.3 μm以上粗粒颗粒的离子质量浓度为no3 - > so4 - 2 > ca2 + > nh4 + >Na + >Cl - >K + >Mg 2+ >F−。5个组分的粒径分布表明，so4 2−、no3−和nh4 +在1 μm以下呈细峰分布，ca2 +、mg2 +、Na +和Cl−呈双峰分布，第二峰大于2.1 μm。反轨迹分析表明，气团可分为三大类。总离子浓度在陆地和混合状态之间具有可比性。在陆相环境中，细态硫酸盐和硝酸盐主要与铵相结合。在整个粒径范围内，过量的硫酸盐和硝酸盐可能以Ca(no3) 2和caso4的形式存在。在海洋环境中，so4.2−、no3−和nh4 +的减少有助于空气质量的改善。除海洋气溶胶外，土壤粉尘和燃煤排放也是海盐型离子（即Na +和Cl−）的重要来源。
Abstract The size distribution of water-soluble inorganic components of urban aerosols in Shanghai was studied. The size-resolved aerosol samples collected by an 8-stage cascade sampler between April and May of 2012 were analyzed by ion chromatography. The ion mass concentrations followed the sequence of SO 4 2− >NO 3 − ~NH 4 + >Ca 2+ >Na + ~Cl − >K + >Mg 2+ >F − for each size fraction below 2.1 μm, while the sequence was NO 3 − >SO 4 −2 >Ca 2+ >NH 4 + >Na + >Cl − >K + >Mg 2+ >F − for coarse mode particles larger than 3.3 μm. The size distribution in 5 fractions showed that SO 4 2− , NO 3 − , and NH 4 + were generally in the fine mode peaking below 1 μm while Ca 2+ , Mg 2+ , Na + , and Cl − were bimodally distributed with a second peak larger than 2.1 μm. Back trajectory analyses revealed that the air masses could be classified into three main groups. The total ion concentrations were comparable between the terrestrial and mixing regimes. In the terrestrial regime, fine mode sulfate and nitrate were predominantly associated with ammonium. The excessive sulfate and nitrate over the whole size range might exist in the forms of Ca(NO 3 ) 2 and CaSO 4 . In the maritime regime, the decrease in SO 4 2− , NO 3 − , and NH 4 + contributed to the improvement in air quality. Besides marine aerosols, local emissions from soil dust and coal combustion were also important sources of sea-salt type ions (i.e., Na + and Cl − ).