| 2015~2017年上海郊区大气新粒子生成特征 |
| 摘要点击 2367 全文点击 674 投稿时间：2019-03-11 修订日期：2019-06-12 |
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| 中文关键词 新粒子生成(NPF) 新粒子增长-缩小 上海郊区 气象要素 化学组分 |
| 英文关键词 new particle formation(NPF) shrinkage Shanghai suburb meteorological element chemical composition |
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| 中文摘要 |
| 本研究利用扫描电迁移率粒径谱仪（SMPS）对上海郊区2015~2017年期间大气新粒子生成进行长期连续观测，结合气象要素、气态污染物和PM2.5化学组分等数据，分析上海郊区新粒子生成特征.结果表明，上海郊区新粒子生成天（NPF）为172 d，占有效天数（942 d）的18.3%；其中典型新粒子生成天（Event）和新粒子增长-缩小天（Shrinkage）分别为150 d和32 d； NPF天占比春、夏季最高，秋季次之，冬季最低.高温低湿、太阳辐射强、风速大和降雨量少的气象条件有利于新粒子生成；南风、西南风和西风期间Event天占比高，气团主要来自环太湖流域植被覆盖和农业种植区，而Non-NPF和Shrinkage天主导风向为东北、东到东南风.与非新粒子生成天（Non-NPF）相比，Event天各季度SO2和O3均高，表明气态硫酸和光化学反应为新粒子生成的关键因素； PM2.5浓度并不均低于Non-NPF天，但PM10值均更高，可能与多相光催化反应有关.Shrinkage天除O3外，其他污染物浓度均最低，较低的气态前体物导致新粒子增长程度有限.PM2.5化学组分显示，Event天NH4+、SO42-和NO3-无机组分秋季平均浓度高于Non-NPF天，其他季节则相反；有机碳各季节平均浓度均高于Non-NPF天； Shrinkage天各组分浓度最低，但春、夏、冬季有机碳占比均高于Non-NPF天；因此有机物在上海郊区新粒子生成及增长过程中有重要贡献. |
| 英文摘要 |
| In this study, long-term continuous monitoring of atmospheric new particle formation was conducted from 2015 to 2017 in the Shanghai suburbs using a scanning mobility particle sizer (SMPS). Combined with meteorological parameters, gaseous pollutants, and PM2.5 chemical composition data, the characterization of new particle formation was analyzed. The results of data analysis showed there were 172 new particle formation (NPF) days in the Shanghai suburbs, accounting for 18.3% of the total effective days (942 d). Typical new particle formation days (Event) and new particle growth-shrinkage (Shrinkage) days were 150 d and 32 d, respectively. The frequency of NPF occurrence was the highest in spring and summer, followed by autumn and winter. Compared with non-new particle formation (Non-NPF) days, Event and Shrinkage days had higher temperature and wind speed, lower humidity, less rainfall, and stronger solar radiation. The ratio of Event days was the highest when the prevailing wind was southerly, southwesterly, or westerly, and when the air masses were mainly from the vegetation cover and agricultural planting areas in the Taihu Lake Basin. The prevailing wind directions for Non-NPF and Shrinkage days were northeasterly and easterly to southeasterly. On the Event days, SO2 and O3 were higher than that on the Non-NPF days, indicating gaseous sulfuric acid and photochemical reactions were key contributors to new particle formation. Higher PM10 concentration was detected on the Event days than on the Non-NPF days, which may be attributed to the photocatalytic reaction. All the pollutant concentrations were the lowest on Shrinkage days, except that of O3. The average concentrations of inorganic components of PM2.5, such as NH4+, SO42-, and NO3- were higher on Event than on Non-NPF days in fall, whereas the opposite results were observed in other seasons. The average concentration of organic carbon on Event days was higher than that on Non-NPF days in each season. The concentrations of PM2.5 components on Shrinkage days were the lowest. However, the ratio of organic carbon on Shrinkage days was higher than that on Non-NPF days in spring, summer, and winter. The higher ratio of organic carbon on the NPF days than on the Non-NPF days suggested an important role of organic matter in the formation and growth of new particles in the suburbs of Shanghai. |
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