| 伊犁河谷夏季PM2.5和PM10中水溶性无机离子浓度特征和形成机制 |
| 摘要点击 2639 全文点击 1933 投稿时间：2022-01-11 修订日期：2022-03-15 |
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| 中文关键词 水溶性无机离子(WSIIs) 二次无机组分 硫氧化率(SOR) 形成机制 伊犁河谷 |
| 英文关键词 water-soluble inorganic ions (WSIIs) secondary inorganic components sulfate oxidation rate (SOR) formation mechanism Ili River Valley |
| 作者 | 单位 | E-mail | | 陈巧 | 中国环境科学研究院, 北京 100012
新疆维吾尔自治区生态环境监测总站, 乌鲁木齐 830011
天津城建大学环境与市政工程学院, 天津 300384 | 1839245665@qq.com | | 谷超 | 新疆维吾尔自治区生态环境监测总站, 乌鲁木齐 830011 | | | 徐涛 | 新疆维吾尔自治区生态环境监测总站, 乌鲁木齐 830011 | | | 周春华 | 伊犁哈萨克自治州环境监测站, 伊宁 839300 | | | 张国涛 | 中国环境科学研究院, 北京 100012 | | | 赵雪艳 | 中国环境科学研究院, 北京 100012 | zhaoxy@craes.org.cn | | 吴丽萍 | 天津城建大学环境与市政工程学院, 天津 300384 | | | 李新琪 | 新疆维吾尔自治区生态环境监测总站, 乌鲁木齐 830011 | 45707398@qq.com | | 杨文 | 中国环境科学研究院, 北京 100012 | |
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| 中文摘要 |
| 区域尺度大气颗粒物的同步观测与分析是制定大气污染防治策略的重要途径.为研究伊犁河谷城市群大气颗粒物和水溶性无机离子的空间分布特征，于2021年7月19~29日期间同步采集伊宁市和周边三县大气颗粒物样品，深入分析了PM2.5和PM10中9种水溶性无机离子（WSIIs）的空间分布特征、存在形式和影响因素，并对二次无机颗粒物的形成机制进行了探讨.结果表明，夏季伊犁河谷城市群ρ（PM2.5）和ρ（PM10）均值分别为（23±3）μg ·m-3和（59±7）μg ·m-3，伊宁市受本地工业源和移动源排放影响，导致其PM2.5浓度在区域中最高；伊宁县受扬尘源和地形影响，使其PM10浓度在区域中最高；而霍城县的良好扩散条件使其PM2.5和PM10浓度最低.PM2.5和PM10中WSIIs占比分别介于28.2%~29.9%和16.0%~20.2%之间.4种主要离子（SO42-、NO3-、NH4+和Ca2+）占到WSIIs的90%左右，在PM2.5中浓度大小排序为：SO42->Ca2+>NH4+>NO3-，在PM10中浓度大小排序为：SO42->Ca2+>NO3->NH4+；相关性研究结果显示4个城市SO42-浓度相近主要是由区域输送所致，而Ca2+在PM2.5和PM10中占比高于国内大部分城市反映出伊犁河谷核心区城市受扬尘源的影响较大.PM2.5和PM10中n（NO3-）/n（SO42-）分别为0.78和0.76，表明伊犁河谷受固定源影响大于移动源；4个城市n（NO3-）/n（SO42-）的大小排序为：伊宁市>霍城县>伊宁县>察县，与各城市机动车保有量大小一致，反映出伊宁市受机动车等移动源的影响高于周边三县.二次组分主要以（NH4）2SO4、NH4HSO4和NH4NO3的形式存在，各城市NH4+与SO42-反应后均有盈余，盈余的铵盐在伊宁市主要以NH4NO3存在，与伊宁市较高的NO2浓度有关.夏季PM2.5和PM10中NOR变化幅度分别为0.03~0.10和0.03~0.16，受夏季高温影响导致NO3-二次转化较弱；SOR分别介于0.21~0.41和0.23~0.44之间，察县相对较高的湿度使其SOR较高，而霍城县受区域输送影响使其SOR高于伊宁市.形成机制表明：察县和伊宁市的SO42-主要由非均相反应生成，伊宁县主要由均相反应产生，而霍城县SO42-的形成机制较为复杂，受到均相反应和非均相反应的共同影响. |
| 英文摘要 |
| The simultaneous observation and analysis of atmospheric particles on a regional scale is an important approach to developing control strategies for air pollution. To study the spatial distribution characteristics of particulate matter and water-soluble inorganic ions in the Ili Valley Urban agglomeration, PM2.5 and PM10 samples were synchronously collected from July 19 to July 29, 2021 in Yining City and the surrounding three counties, and then nine types of water-soluble inorganic ions (WSIIs) were analyzed. The spatial distribution characteristics, existence form of WSIIs, and influencing factors were discussed in depth. The results showed that the average ρ(PM2.5) and ρ(PM10) in the Ili River Valley urban agglomeration in summer were 23 μg·m-3 and 59 μg·m-3, respectively. The emission of local industrial and mobile sources in Yining City was higher than that of the surrounding three counties, resulting in the highest ρ(PM2.5) in the region (25 μg·m-3). Due to the influence of dust sources and topography, the ρ(PM10) in Yining county was the highest in the region (63 μg·m-3). Huocheng county is located upwind of the region, and these favorable diffusion conditions resulted in the lowest ρ(PM2.5) and ρ(PM10) (20 μg·m-3 and 49 μg·m-3, respectively). The concentrations of WSIIs in PM2.5 and PM10 ranged from 28.2%-29.9% and 16.0%-20.2%, respectively. The four main ions (SO42-, NO3-, NH4+, and Ca2+) accounted for approximately 90% of WSIIs mass concentrations. The concentration order of the four main ions in PM2.5 was SO42->Ca2+>NH4+>NO3- and SO42->Ca2+>NO3->NH4+ in PM10. The results of correlation analysis showed that the similar SO42- concentrations in the four cities were mainly caused by regional transport. Ca2+ was the highest-concentration ion in PM10 of Yining City and Qapqal Xibe Autonomous county, and the proportion of Ca2+ was significantly higher than that in most cities in China, which reflected that the cities in the core area of the Ili Valley were greatly affected by the dust sources. The ratios of n(NO3-)/n(SO42-) in PM2.5 and PM10 were 0.78 and 0.76, respectively, indicating that the influence of stationary sources was greater than that of mobile sources. The ratio of n(NO3-)/n(SO42-) in Yining City>Huocheng county>Yining county>Qapqal Xibe Autonomous county, which was consistent with the motor vehicle populations of the four cities, reflecting that Yining City was affected by motor vehicle sources more than the surrounding three counties. The secondary components mainly existed in the form of (NH4)2SO4, NH4HSO4, and NH4NO3. There was excess ammonia after the reaction between NH4+ and SO42- in each city. NH4NO3 mainly existed in Yining City, which was mainly related to high NO2 in Yining City. The NOR of the four cities were 0.03-0.10 and 0.03-0.16 in PM2.5 and PM10, respectively, and the secondary transformation of NO3- was weak due to the influence of high temperatures in summer. The SOR were 0.21-0.41 and 0.23-0.44, respectively. The SOR of Qapqal Xibe Autonomous county was the highest due to the relatively high humidity, whereas the SOR of Huocheng county was higher than that of the three sites in Yining City due to the influence of regional transportation. The formation mechanisms showed that SO42- in Qapqal Xibe Autonomous county and Yining City were mainly produced by the heterogeneous reaction, and in Yining county it was mainly formed via the homogeneous reaction. However, the formation mechanism in Huocheng county was complex and was affected by both homogeneous and heterogeneous reactions. |
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