中文关键词无机离子乙二酸左旋葡聚糖PM_2.5聊城 英文关键词inorganic ionsoxalic acidlevoglucosanPM_2.5Liaocheng City

作者	单位	E-mail
衣雅男	聊城大学环境与规划学院, 聊城 252000	yiyanan6902@163.com
侯战方	聊城大学环境与规划学院, 聊城 252000 中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室, 西安 710061	houzhanfang@lcu.edu.cn
孟静静	聊城大学环境与规划学院, 聊城 252000 中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室, 西安 710061
燕丽	生态环境部环境规划院, 北京 100012
王心培	华东师范大学地理科学学院, 地理信息科学教育部重点实验室, 上海 200062
刘晓迪	聊城大学环境与规划学院, 聊城 252000
伏梦璇	聊城大学环境与规划学院, 聊城 252000
魏本杰	聊城大学环境与规划学院, 聊城 252000

中文摘要 为探究聊城市冬季PM_2.5中水溶性物质的昼夜变化特征及其来源，于2017年1~2月进行PM_2.5样品采集，对其水溶性无机离子、乙二酸和左旋葡聚糖等水溶性化合物进行分析，并采用主成分分析-多元线性回归模型（PCA-MLR）对其来源进行解析.结果表明，采样期间聊城市PM_2.5平均质量浓度为（132.6±65.4）μg·m^-3，是国家二级标准的1.8倍，且夜晚PM_2.5的污染程度略高于白天.SNA（SO₄^2-、NO₃^-和NH₄⁺）是聊城市PM_2.5中最主要的水溶性离子，在白天与夜晚占总离子的质量分数为73.4%和77.1%，说明聊城市冬季二次污染较严重.白天与夜晚阴阳离子平衡当量比值（AE/CE）都小于1，说明PM_2.5呈碱性，且夜晚PM_2.5的酸性比白天强.无论在白天还是晚上，NH₄⁺的主要存在形态均为NH₄HSO₄和NH₄NO₃.通过相关性分析，证实了乙二酸是在液相中经酸催化的二次氧化反应形成的，且受生物质燃烧的影响很强.通过PCA-MLR模型分析可知，聊城市冬季PM_2.5中的水溶性化合物主要来自机动车尾气及其二次氧化、生物质燃烧，而受矿物粉尘与煤炭燃烧的影响较小. 英文摘要 To investigate the diurnal variations and sources of water-soluble compounds in Liaocheng City, PM_2.5 samples were collected between January and February 2017. The PM_2.5 samples were analyzed for the compositions, concentrations, and sources of water-soluble inorganic ions, oxalic acid, and levoglucosan. The sources of these chemical compound were investigated using principal component analysis (PCA) and multiple linear regression (MLR) modeling. The results showed that the mass concentrations of PM_2.5during the nighttime were higher than those during the daytime, and the average concentrations exceeded the National Ambient Air Quality Standard (GB 3095-2012) by more than 1.8 times. Moreover, atmospheric pollution was worse during the day than during the night. SNA (SO₄^2-, NO₃^-, and NH₄⁺) were the dominant species among the inorganic ions, the relative abundance of which with respect to the total concentrations of inorganic ions was 73.4% and 77.1% during the daytime and nighttime, respectively. The ratios of anion to cation equivalents (AE/CE) were less than one, suggesting that the PM_2.5 was slightly alkaline, and the degree of acidity at night was stronger than during the day. The results of the correlation analyses suggested that aqueous-phase oxidation was the major formation pathway of oxalic acid, which is driven by acid-catalyzed oxidation. The oxalic acid was mainly influenced by biomass burning during the winter in Liaocheng City. The results of the PCA-MLR model suggested that water-soluble compounds in Liaocheng City were mostly from vehicular emissions and secondary oxidation, biomass burning, while the impacts of mineral dust and coal burning were relatively minor.

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