| 《大气污染防治行动计划》后期成都大气PM2.5中水溶性无机离子特征 |
| 摘要点击 2449 全文点击 648 投稿时间：2021-04-26 修订日期：2021-05-31 |
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| 中文关键词 PM2.5 水溶性无机离子 季节变化 源解析 成都 |
| 英文关键词 PM2.5 water-soluble inorganic ions seasonal variation source apportionment Chengdu |
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| 中文摘要 |
| 为探究《大气污染防治行动计划》实施后期成都大气PM2.5中水溶性无机离子（WSIIs）季节变化及来源等特征，本研究于2016~2017年在成都城区进行了分季节PM2.5样品的连续采集，对其中WSIIs进行了全面分析.结果表明，成都市年均ρ（PM2.5）和ρ（WSIIs）分别为（114.0±76.4）μg·m-3和（41.2±31.3）μg·m-3，ρ（WSIIs）可占ρ（PM2.5）的36.1%，其季节贡献特征为：秋季（39.5%） > 冬季（38.2%） > 春季（32.5%） > 夏季（28.9%）.全年及各季节ρ（PM2.5）和ρ（WSIIs）均值均表现为夜间高于白天，且昼夜差异幅度呈现出了明显的季节变化特征.SNA（SO42-、NO3-和NH4+）是WSIIs的重要组成，在春、夏、秋和冬这4季中可占到整体ρ（WSIIs）的84.2%、86.6%、86.3%和87.0%.秋和冬的ρ（NO3-）/ρ（SO42-）比值分别为1.1和1.6，高于春和夏的0.96和0.57，移动源和固定源相对贡献随季节变化特征明显.观测期间WSIIs主要来源包括二次生成、扬尘源和燃烧源.后向轨迹分析表明，来自成都东部地区的近地气团对应的ρ（PM2.5）低于源自西部的高空气团，就WSIIs构成而言，东部气团对应的ρ（SO42-）占比高于西部气团，而西部气团对应的ρ（NO3-）占比则高于前者. |
| 英文摘要 |
| The purpose of this study was to investigate the seasonal variation and sources of water-soluble inorganic ions (WSIIs) in PM2.5 during the later stage of the Air Pollution Prevention and Control Action Plan in Chengdu. PM2.5 samples in different seasons were collected from 2016 to 2017 in the urban area of Chengdu, and the WSIIs in PM2.5 were analyzed. The results show that the annual average ρ(PM2.5) and ρ(WSIIs) in Chengdu were (114.0±76.4) μg·m-3 and (41.2±31.3) μg·m-3, respectively. ρ(WSIIs) accounted for 36.1% of ρ(PM2.5). The seasonal contributions of ρ(WSIIs) to ρ(PM2.5) were:autumn (39.5%) > winter (38.2%) > spring (32.5%) > summer (28.9%). The average ρ(PM2.5) and ρ(WSIIs) at night throughout the year and during each season were higher than those during the day, and the diurnal difference showed obvious seasonal variation. SNA (SO42-, NO3-, and NH4+) were important components of WSIIs and accounted for 84.2%, 86.6%, 86.3%, and 87.0% of the total ρ(WSIIs) in spring, summer, autumn, and winter, respectively. The ρ(NO3-)/ρ(SO42-) ratios in autumn and winter were 1.1 and 1.6, respectively, which were higher than the 0.96 and 0.57 ratios in spring and summer, respectively. This means that the contributions of mobile and stationary sources varied significantly with the seasons. The main sources of WSIIs during the observation period included secondary formation, dust, and combustion sources. The backward trajectory analysis shows that ρ(PM2.5) of the near-surface air mass from the eastern areas of Chengdu were lower than that of the upper air mass from the western areas. In terms of WSII composition, the contribution of ρ(SO42-) from the eastern air masses was higher than that from the western air masses, whereas the contribution of ρ(NO3-) from the western air masses was higher than the former. |
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