| 南京北郊四季PM2.5中有机胺的污染特征及来源解析 |
| 摘要点击 1958 全文点击 665 投稿时间：2019-08-26 修订日期：2019-09-24 |
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| 中文关键词 有机胺 离子色谱 新粒子生成 正交矩阵因子解析(PMF) 源解析 |
| 英文关键词 amines ion chromatography new particle formation positive matrix factorization (PMF) source apportionment |
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| 中文摘要 |
| 2017年12月至2018年11月在南京北郊采集了大气PM2.5样品，对其中的有机胺、主要水溶性离子、有机碳和元素碳进行了定量分析.共测定南京北郊大气PM2.5中5种有机胺：甲胺、乙胺、二甲胺、三甲胺和苯胺.有机胺年平均总浓度为（54.2±29.2）ng·m-3，其中最丰富的物种为二甲胺[年均值：（20.2±13.7）ng·m-3]，其次为甲胺[年均值：（13.1±6.3）ng·m-3]、三甲胺[年均值：（8.6±4.1）ng·m-3]、乙胺[年均值：（6.3±4.1）ng·m-3]和苯胺[年均值：（5.9±3.9）ng·m-3]，有机胺总浓度呈现出明显的季节变化，表现为夏季 > 秋季 > 春季 > 冬季.污染天有机胺的浓度大于清洁天，主要是受大气颗粒物酸性影响大气有机胺气/粒转换所致，并且大气颗粒物酸性也是导致夏季高温条件下颗粒态有机胺仍高于其它季节的另一原因.在新粒子生长天，发现有机胺的浓度会有所增加.PMF法溯源结果显示南京北郊大气PM2.5中主要有6种有机胺排放源：即工业源、农业源、生物质燃烧、机动车排放、二次源和道路扬尘.其中甲胺、乙胺主要来源于二次源和机动车排放；二甲胺、三甲胺主要来源于生物质燃烧、二次源和机动车排放；苯胺主要来源于工业排放和生物质燃烧.有机胺的来源具有显著的季节差异，春季秋季道路扬尘源占比较高，夏季二次源为有机胺主要的污染源，冬季机动车排放源和生物质燃烧源有一定提升.而有机胺的昼夜差异并不明显，二次源、机动车排放源以及生物质燃烧源是3个主要影响因素. |
| 英文摘要 |
| PM2.5 samples were collected from December 2017 to November 2018 at a northern suburb site of Nanjing. The concentrations of five amines, major water-soluble ions, organic carbon, and elemental carbon were determined. The five amines measured were methylamine, ethylamine, dimethylamine, trimethylamine, and aniline. The annual average of the total amine concentration was (54.2±29.2) ng·m-3. Among these, dimethylamine was the most abundant[annual average:(20.2±13.7) ng·m-3], followed by methylamine[annual average:(13.1±6.3) ng·m-3], trimethylamine[annual average:(8.6±4.1) ng·m-3], ethylamine[annual average:(6.3±4.1) ng·m-3], and aniline[annual average:(5.9±3.9) ng·m-3]. The total amine concentration showed explicit seasonal variations:summer > autumn > spring > winter. The amine concentration on polluted days was higher than that on clean days. This may be influenced by aerosol acidity, promoting the partitioning of gaseous amine into the particulate phase. Aerosol acidity was also the major reason for the higher concentration of amine observed in summer than in other seasons. During new particle formation events, the concentrations of amines increased substantially. Positive matrix factorization (PMF) was utilized to identify the potential sources of amines, identifying six sources:industrial emission, agriculture emission, biomass burning, automobile emission, secondary formation, and dust. Methylamine and ethylamine mainly originated from secondary formation and automobile emissions. Dimethylamine and trimethylamine mainly originated from biomass burning, secondary formation, and automobile emissions; Aniline mainly originated from industrial emissions and biomass burning. A significant seasonal difference is observed with respect to the sources of amines. In spring and autumn, road dust sources account for a relatively high proportion. In summer, secondary sources are the main sources of amines. However, the diurnal variations of amine are not evident, and the secondary source, motor vehicle emission, and biomass combustion are the three main influencing factors. |
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