| 长三角城郊冬夏PM2.5中铵盐的形成过程及来源解析 |
| 摘要点击 2553 全文点击 785 投稿时间：2022-12-29 修订日期：2023-03-01 |
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| 中文关键词 PM2.5 气溶胶铵盐 稳定同位素技术 δ15N-NH4+ 源解析 |
| 英文关键词 PM2.5 aerosol ammonium sable isotope technology δ15N-NH4+ source apportionment |
| 作者 | 单位 | E-mail | | 项妍琨 | 南京信息工程大学应用气象学院, 南京 210044
南京信息工程大学大气环境中心, 教育部气候与环境变化国际合作联合实验室, 南京 210044 | xyk6688@126.com | | 曹芳 | 南京信息工程大学应用气象学院, 南京 210044
南京信息工程大学大气环境中心, 教育部气候与环境变化国际合作联合实验室, 南京 210044 | caofangle@163.com | | 张雯淇 | 南京信息工程大学应用气象学院, 南京 210044
南京信息工程大学大气环境中心, 教育部气候与环境变化国际合作联合实验室, 南京 210044
浙江省宁波市气象台, 宁波 315012 | | | 范美益 | 南京信息工程大学应用气象学院, 南京 210044
南京信息工程大学大气环境中心, 教育部气候与环境变化国际合作联合实验室, 南京 210044 | | | 章炎麟 | 南京信息工程大学应用气象学院, 南京 210044
南京信息工程大学大气环境中心, 教育部气候与环境变化国际合作联合实验室, 南京 210044 | |
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| 中文摘要 |
| 气溶胶铵盐（p-NH4+）作为大气气溶胶细颗粒物（PM2.5）中主要的二次无机气溶胶（SIAs）污染物，在灰霾形成过程中起重要作用.然而对于大气中NHx（p-NH4+和NH3）各潜在来源的贡献仍存在争议.分别于2015年冬季和夏季在苏州东山半岛采集了3 h高频大气气溶胶PM2.5样品，测定总氮（TN）和p-NH4+的质量浓度及其δ15N同位素比值，并结合贝叶斯模型（SIAR）模拟，定量解析了PM2.5中铵盐的生成过程和来源.结果表明，在冬夏两季SO42-、NO3-和NH4+均为主要的水溶性离子，占比总和超过70%.PM2.5、TN和p-NH4+质量浓度变化趋势一致，且冬季均是夏季的2~3倍.δ15N-NH4+值在冬季和夏季均与浓度呈正比，然而冬季整体（-1.7‰±4.3‰）却比夏季整体（7.8‰±5.9‰）更低，这表明每个季节内δ15N-NH4+值的变化是由于不同潜在来源的贡献率不同造成的，而冬夏两季δ15N-NH4+值的差异则主要是由于铵-氨气粒分配时的氮同位素分馏导致的.SIAR溯源结果显示，非农业来源是东山地区p-NH4+主导来源，冬季贡献率为59%，夏季贡献率为69%，相较于农业来源挥发形成的NH3，化石燃料燃烧生成的NH3更易于在大气中生成气溶胶铵盐. |
| 英文摘要 |
| As the main pollutants of secondary inorganic aerosols(SIAs) in fine particulate matter(PM2.5), aerosol ammonium(p-NH4+) plays a significant role in the formation of haze. However, the contribution ratio of each potential source of atmospheric NHx(p-NH4+ and NH3) still remains controversial. In this study, 3 h high-frequency PM2.5 samples were collected in Dongshan, Suzhou during winter and summer in 2015, respectively. Meanwhile, we determined concentrations and δ15N isotope ratios of total nitrogen(TN) and p-NH4+ and quantitatively analyzed formation processes and sources of p-NH4+ based on the Bayesian mixing model(SIAR). SO42-, NO3-, and NH4+ were the main water-soluble ions(WSIs) both in winter and summer, accounting for more than 70% in general. The concentration change trends of PM2.5, TN, and p-NH4+ were consistent, and the concentrations in winter were 2-3 times those in summer. The δ15N-NH4+ value was in direct proportion to the p-NH4+ concentration both in winter and summer. However, δ15N-NH4+ values in winter(-1.7‰±4.3‰) were lower than those in summer(7.8‰±5.9‰). This indicated that the differences in δ15N-NH4+ were caused by different contribution rates of each potential source within each season, whereas it was mainly led by nitrogen isotope fractionation during ammonium-ammonia gas particle distribution in different seasons. The SIAR model calculated that non-agricultural sources were the dominant source of p-NH4+ in Dongshan, with the contribution rate of 59% in winter and 69% in summer, which indicated that NH3 emitted by fossil fuel combustion more easily formed particle aerosol ammonium than that volatilized from agricultural sources. |
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