| 摘要: |
| 为研究上海市闵行区大气降水化学特征及来源，以2006—2020年上海市闵行区大气降水监测数据为依据，对大气降水量、pH值、电导率(EC)和主要离子进行了统计分析。结果表明：2006—2020年上海市闵行区大气降水呈酸性，pH值范围为4.41~5.19，酸雨频率呈下降趋势；EC变化范围为1.26~3.67 mS/m，平均值为2.32 mS/m；夏季pH值最高，酸雨发生频率、EC和总离子浓度最低，冬季pH值最低，总离子浓度最高。大气降水中各离子组分浓度占比大小排序为：SO2-4＞NH+4＞NO-3＞Ca2+＞Cl-＞Na+＞Mg2+＞F-＞K+，主要阴、阳离子SO2-4、Ca2+和NH+4浓度呈明显下降趋势，NO-3浓度变化较平稳；SO2-4与NO-3的浓度比范围为0.94~3.59，呈波动下降趋势，降雨类型由硫酸型逐步转为混合型。因子分析及相关性分析显示，因子1中所有的离子成分都有较大的载荷，各离子在来源上可能具有一定的共性，Ca2+与Mg2+、K+表现出显著相关，其可能来源于地壳组分；Cl-与K+、Mg2+、Ca2+的相关性显著，Mg2+、K+与Cl-、Na+有强相关性，表明海洋输送及生物质燃烧对大气降水化学组成的影响；NO-3、SO2-4和NH+4在因子2中为高荷载，且有很好的相关性，它们可能有相似的来源或形成化合物共同存在。 |
| 关键词: 大气降水 酸雨 化学特征 来源分析 上海市 |
| DOI： |
| 分类号:X517 |
| 基金项目:上海市闵行区科委基金资助项目（2020MHZ092） |
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| Chemical Characteristics and Source Apportionment of Atmospheric Precipitation in Minhang District of Shanghai from 2006 to 2020 |
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LI Bin，HUANG Jun-mei
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Shanghai Minhang District Environmental Monitoring Station，Shanghai 201199，China
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| Abstract: |
| The observational data including pH，electrical conductivity （EC）and ion concentration in Minhang District of Shanghai from 2006 to 2020 was statistically analyzed to study the chemical characteristics and sources of atmospheric precipitation．The results showed that the pH value ranged from 4.41 to 5.19 of the precipitation samples from 2006 to 2020．The frequency of acid precipitation was found to decrease，and the acid rain pollution had been improved．The EC value ranged from 1.26 to 3.67 mS/m，with an average value 2.32 mS/m．The pH value was the highest in summer，while the frequency of acid rain，EC and total ion concentration were the lowest．In winter，the pH value was the lowest while total ion concentration was the highest．The order of concentration proportion of each ion component in atmospheric precipitation was SO2-4＞NH+4＞NO-3＞Ca2+＞Cl-＞Na+＞Mg2+＞F-＞K+．The main ions such as SO2-4，Ca2+and NH+4 decreased significantly，while the concentration of NO-3remained relatively stable．The ratio of SO2-4 to NO-3was 0.94 to 3.59，showing a decreasing trend over the past decades．The rainfall type was shifting gradually from sulfuric to sulfuric nitrous mixed．Pearson correlation analysis and factor analysis indicated that all ionic components had a large load in factoe 1．Ca2+ had a significant correlation with Mg2+ and K+，which may be derived from crustal components．Cl- had a significant correlation with K+，Mg2+，Ca2+，and relatively good correlation were observed among Mg2+，K+，Cl-，Na+，indicating the influence of marine transportation and biomass burning on the chemical composition of atmospheric precipitation．NO-3，SO2-4and NH+4 were high loaded in the second factor and good correlations were observed，which indicated similar sources or the formation of compounds． |
| Key words: Atmospheric precipitation Acid rain Chemical characteristics Source apportionment Shanghai |
