| 济南市夏、冬季PM2.5中化学组分的季节变化特征及来源解析 |
| 摘要点击 2997 全文点击 926 投稿时间：2018-01-09 修订日期：2018-03-08 |
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| 中文关键词 水溶性离子 碳质组分 季节变化特征 济南市 PM2.5 |
| 英文关键词 water-soluble ions carbonaceous component seasonal variation Ji'nan City PM2.5 |
| 作者 | 单位 | E-mail | | 刘晓迪 | 聊城大学环境与规划学院, 聊城 252000 | 1610140206@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 | mengjingjing@lcu.edu.cn | | 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 | | | 李静 | 聊城大学环境与规划学院, 聊城 252000 | | | 邢继钊 | 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 | | | 张二勋 | 聊城大学环境与规划学院, 聊城 252000 | | | 刘加珍 | 聊城大学环境与规划学院, 聊城 252000 | | | 董杰 | 聊城大学环境与规划学院, 聊城 252000 | |
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| 中文摘要 |
| 为探究济南市大气气溶胶中化学组分的季节变化特征，于2015年夏季、冬季分别连续进行1个月的PM2.5样品采集，并分析无机离子、碳质组分与水溶性二次有机碳（WSOC）的组成、浓度水平及来源.结果表明，济南市冬季PM2.5的质量浓度[（158.3±95.3）μg·m-3]约为夏季[（75.3±25.9）μg·m-3]的2倍，在我国其浓度处于中上等水平.无机离子的总浓度呈夏低冬高的季节变化特征，其中SO42-、NO3-、NH4+是浓度最高的3种离子，且这3种离子的相关性均较好，NH4+在夏季和冬季均以（NH4）2SO4和NH4NO3的形式存在.大气中存在较高程度的SO2和NO2的二次氧化，其中硫氧化率（SOR）呈夏高冬低的变化特征，而氮氧化率（NOR）呈相反的季节变化特征.通过分析PM2.5中阴、阳离子电荷平衡可知，PM2.5呈弱碱性.基于热力学模型ISORROPIA-Ⅱ，结果表明冬季PM2.5的酸性比夏季强.OC与EC浓度均呈夏低冬高的变化特征，由OC/EC的比值、WSOC/OC的比值和估算的二次有机碳（SOC）的浓度可知，夏季二次污染的程度比冬季更为严重.主成分分析（PCA）结果表明，济南市夏季无机离子主要来自二次氧化及生物质燃烧，而冬季无机离子主要来自煤炭燃烧及其产生的前体物经光化学氧化形成的二次污染物. |
| 英文摘要 |
| To investigate seasonal variations in the chemical compositions of aerosols in Ji'nan City, PM2.5 samples were collected during summer and winter in 2015. The sampling period lasted one month during each season. PM2.5 samples were analyzed for the composition, concentration, and sources of water-soluble inorganic ions, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC). Results showed that mass concentrations of PM2.5 in winter were about twice those in summer, and concentration levels varied between fine and excellent. The concentrations of total water-soluble inorganic ions were also higher in winter than in summer, with SO42-, NO3-, and NH4+ being the dominant species and well correlated with each other. NH4+ in PM2.5 mostly existed in the form of (NH4)2SO4 and NH4NO3 in both summer and winter. There was strong secondary oxidation of SO2 and NO2. The sulfate oxidizing rate (SOR) was higher in summer than in winter, while the nitrate oxidizing rate (NOR) showed the opposite trend. The ratio of anions to cations in both summer and winter were less than one, suggesting that PM2.5 were slightly alkaline. The ISORROPIA-Ⅱ mode showed that acidity in winter was stronger than in summer. Concentations of OC and EC were both higher in winter than in summer. The ratios of OC to EC and WSOC to OC and estimated concentrations of secondary organic carbon (SOC) showed that secondary pollution was more serious in winter than in summer. Principal component analysis(PCA)indicated that the major sources contributing to inorganic ions were secondary oxidation and biomass burning in summer, and coal combustion and secondary pollutants formed by chemical oxidation of precursors emitted from coal combustion in winter. |
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