| 成都市大气颗粒物粒径分布及水溶性离子组成的季节变化特征 |
| 摘要点击 2657 全文点击 851 投稿时间：2017-02-26 修订日期：2017-04-29 |
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| 中文关键词 成都 大气颗粒物 水溶性离子 粒径分布 来源 |
| 英文关键词 Chengdu atmospheric particles water-soluble ions size distribution source |
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| 中文摘要 |
| 利用Anderson冲击式分级采样器，于2012年2月~2013年1月在成都市城东成都理工大学校园内按月采集了不同粒径的大气颗粒物样品，分析了颗粒物样品的质量浓度以及9种水溶性离子含量.结果表明，采样期间成都市PM2.1和PM11的年平均浓度分别为（125.9±56.14）μg·m-3和（224.5±83.64）μg·m-3，颗粒物浓度冬季最高，春季次之，秋季浓度最低；成都市水溶性离子浓度平均水平为37.15 μg·m-3，其中检测的9种离子浓度从大到小顺序依次为SO42- > NO3- > NH4+ > Ca2+ > Cl- > Mg2+ > K+ > Na+ > F-，SO42-、NO3-和NH4+占总水溶性离子的78%，是主要的离子组分.SO42-、NO3-、NH4+呈单峰分布，其主要分布于细粒子中；Ca2+和F-也呈单峰分布，但是主要分布在粗粒子中；Cl-和K+粒径分布相似，Mg2+和Na+分布相似，均呈双峰分布.成都市冬、春季节粗、细颗粒物中的水溶性离子浓度均明显高于夏、秋季节.结合离子相关性分析，细颗粒物中的SO42-、NO3-和NH4+可能主要以（NH4）2SO4或NH4HSO4、NH4NO3的形式存在，而粗颗粒物中的主要离子组分SO42-、NO3-和Ca2+则可能以Ca（NO3）2、CaSO4等形式存在.主成分分析结果表明，颗粒物中水溶性离子主要来自二次过程、土壤扬尘、生物质燃烧和农业源. |
| 英文摘要 |
| Size-resolved atmospheric particles were collected monthly from February 2012 to January 2013 on the campus of Chengdu University of Technology using the Anderson multi-stage impactor sampler. The mass concentrations of these samples and the contents of nine water-soluble ion species were analyzed. The results showed that the annual average concentrations of PM2.1 and PM11 in Chengdu during the sampling period were (125.9±56.14) μg·m-3 and (224.5±83.64) μg·m-3, respectively. The highest mass concentration of particulate matter was observed in winter, followed by spring while the lowest was in autumn. The average content of water-soluble ions in particulate matter in Chengdu was about 37.15 μg·m-3 and the order of water-soluble ion mass concentrations was SO42- > NO3- > NH4+ > Ca2+ > Cl- > Mg2+ > K+ > Na+ > F-. Meanwhile, SO42-, NO3-, and NH4+ were the major water-soluble ionic components that accounted for 78% of total water-soluble ions. Unimodal distribution was observed for SO42-, NO3-, and NH4+ mainly in fine particles, while Ca2+ and F- were concentrated in coarse particles and their distribution was also unimodal. Similar size distributions were found for Cl- and K+, as well as Mg2+ and Na+, both of which were bimodal. The content of water-soluble ions in both fine and coarse particles during winter and spring was significantly higher than that in summer and autumn in Chengdu. Based on the correlation analysis for major ions, SO42-, NO3-, and NH4+ in fine particles are likely in the form of (NH4)2SO4, NH4HSO4, and NH4NO3. In coarse particles, the major water-soluble ions (i.e. SO42-, NO3-, and Ca2+) might exist in the forms of Ca(NO3)2 and CaSO4. The secondary formation processes, soil dust, and biomass burning are the major sources of water-soluble ion species in the particulate matter in Chengdu. |
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