| 摘要: |
| 于2020年6月—2021年5月，应用相关分析、富集因子（EF）以及正定矩阵因子分解模型（PMF）和气团来源分析对东南沿海岛屿平潭大气降水化学特征及来源进行了综合评价与分析。结果表明，平潭大气降水pH值为3.96~7.49，平均值为4.78；电导率（EC）为4.9~342.0 μs/cm,平均值为24.4 μs/cm，高于我国降水背景点值；大气降水中各离子组分当量浓度排序为：Cl-> Na+> SO2-4> NO-3> Ca2+> NH+4> Mg2+> K+> F-> NO-2，Cl-和Na+是降水中占比最大的阴、阳离子，其当量浓度占总离子当量浓度的51.4%；NO-3对平潭大气降水酸化的贡献较高（55.9%），且有77%的大气降水酸度被碱性物质中和，其中铵根离子（NH+4）和钙离子（Ca2+）有着较强的中和能力。富集因子分析结果表明，除海洋源外，地壳源和人为源也是平潭大气降水离子的主要来源；PMF模型结果显示，海洋源、人为源、地壳源和燃烧源分别贡献了平潭大气降水离子的61.1%，23.8%，10.0%和5.1%；气团来源分析结果表明，区域传输对平潭大气降水离子分布及空气质量影响显著，京津冀和长三角地区排放的人为污染物可以经海上传输通道由北至南影响我国下风向地区，给沿海地区大气细颗粒物（PM2.5）与臭氧（O3）协同控制带来挑战。 |
| 关键词: 大气降水 化学组成 来源分析 岛屿 平潭 |
| DOI： |
| 分类号:X511 |
| 基金项目:福建省生态环境厅环保科技计划项目（2022R005） |
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| Chemical Characteristics and Source Apportionment of Precipitation in a Typical Coastal Island City of Southeastern China |
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CHEN Nai-hua
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Pingtan Environmental Monitoring Center of Fujian, Pingtan, Fujian 350400, China
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| Abstract: |
| Chemical characteristics and source apportionment of precipitation from June 2020 to May 2021 were evaluated and analyzed using correlation analysis, the enrichment factor (EF), the positive matrix factorization (PMF) model, and air mass source analysis in Pingtan, a typical coastal island city in southeastern China. The results showed that, during the period of sampling, pH value varied from 3.96 to 7.49, with a volume weighted mean (VWM) of 4.78, and the EC ranged from 4.9 to 342.0 μs/cm, with a VWM of 24.4 μs/cm. The pH and EC were higher than those in the precipitation background areas in our country. The concentration of each ion in precipitation was in the following order: Cl-> Na+> SO2-4> NO-3> Ca2+> NH+4> Mg2+> K+> F-> NO-2. Cl-and Na+were the most abundant anion and cation in precipitation, accounting for 51.4% of the total ions. 55.9% of the acidity of precipitation came from the contribution of NO-3 and 77% of the acidity were neutralized by alkaline substances, in which NH+4 and Ca2+ were the dominant neutralization substances in the precipitation. By EF analysis, it was discovered that, in addition to marine, crustal and anthropogenic emissions were the main sources of precipitation ions in Pingtan. Four sources were identified by PMF, including marine (61.1%), anthropogenic emissions (23.8%), crust (10.0%), and burning (5.1%). The air mass source analysis indicated that regional transport has a significant effect on precipitation chemistry and air quality in Pingtan. Pollutants from the Beijing Tianjin Hebei region and the Yangtze River Delta region affected downwind areas through the maritime transport channel, which brings challenges to the coordinated control of PM2.5and O3 in coastal areas. |
| Key words: Precipitation Chemical composition Source apportionment Island area Pingtan |
