常州市PM_(2.5)中水溶性离子组分污染特征及来源分析  

Pollution Characteristics and Sources of Water-soluble Ions in PM_(2.5) in Changzhou City

作　　者：刘敬琰 胡彦钧 叶招莲[1] 赵竹子 LIU Jing-yan;HU Yan-jun;YE Zhao-lian;ZHAO Zhu-zi(School of Resources and Environmental Engineering,Jiangsu University of Technology,Changzhou,213001,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Science,Xi'an 710075,China)

机构地区：[1]江苏理工学院资源与环境工程学院,江苏常州213001 [2]黄土与第四纪地质国家重点实验室,中国科学院地球环境研究所,陕西西安710075

出　　处：《长江流域资源与环境》2024年第8期1753-1767,共15页Resources and Environment in the Yangtze Basin

基　　金：黄土与第四纪地质国家重点实验室开放基金(SKLLQG1944);江苏省双创博士人才项目(2020-30865);江苏理工学院研究生实践创新计划项目(XSJCX23_95)。

摘　　要：常州是长三角中部重要的现代制造业基地,是长三角地区25个监测城市点中空气污染较为严重的城市之一;为研究常州市大气细颗粒物(PM_(2.5))中水溶性离子的污染特征,于2020~2021年春(2020年5月)、夏(2020年7月)、秋(2020年9月)以及冬(2021年1月),于常州城区进行了为期4个月PM_(2.5)样品的采集,获得PM_(2.5)的质量浓度及主要水溶性离子的质量浓度,结合相关性分析、后向轨迹模型和主成分分析等方法,探讨了不同季节、不同污染阶段水溶性离子组分的变化特征及主要来源。结果显示,采样期间,常州市PM_(2.5)的年均浓度51.88±20.47μg/m^(3),是GB3095-2012中规定的PM_(2.5)年均二级浓度限值的1.5倍,其季节特征为冬季>春季>夏季>秋季;水溶性离子年均总质量浓度为24.37±11.54μg/m^(3),在污染最严重的冬季,离子对PM_(2.5)的贡献率高达56.24%,显著高于其他季节,NH_(4)^(+)、NO_(3)^(-)和Cl^(-)在冬季显著升高,反映出燃烧排放源、机动车排放及其二次生成源的重要影响。硫氧化速率(SOR)和氮氧化速率(NOR)分析结果表明,NOR(0.14±0.07)小于SOR(0.40±0.10),表明相同大气背景下,SO_(2)的二次转化率更高;两者季节变化趋势不同,SOR和NOR的差异分别受相对湿度的影响和NH_(4)^(+)浓度及周边交通源的影响。进一步对不同污染阶段的离子特征展开分析,从洁净阶段到污染阶段,SOR和NOR都有不同程度的升高,表明污染阶段SO_(2)和NOx的转化率更高;比较不同污染阶段下离子的百分占比发现,在相对洁净时期,PM_(2.5)中的离子组分表现为以硫酸盐和钙离子为主的类型;而在相对污染较重时期,硝酸根和铵根的大幅度提升是导致污染产生的重要因素。主成分分析结果表明,冬季常州主要受到燃烧排放源(32.23%)、机动车、二次气溶胶(29.97%)以及土壤源(22.63%)的影响;夏季则主要受到二次气溶胶和燃烧排放混合源(44.20%)、土壤源和海盐源(2As an important modern manufacturing base in the middle of the Yangtze River Delta,Changzhou is one of the 25 monitored cities with severe air pollution.To investigate the pollution characteristics of watersoluble ions in atmospheric fine particulate matter(PM_(2.5)),PM_(2.5)samples were collected in urban Changzhou for four months(spring(May 2020),summer(July 2020),autumn(September 2020),and winter(January 2021)).The mass concentration of PM_(2.5)and water-soluble inorganic ions(WSIIs)were determined,and the chemical characteristics,seasonal differences and main sources of water-soluble ions were investigated by using the multiple-technique analysis,combined correlation analysis,HYSPLIT modelling and primary component analysis.The results showed that during the sampling period,the annual average concentration of PM_(2.5)was 51.88±20.47μg/m^(3),which was 1.5 times higher than the annual average PM_(2.5)concentration limit set by GB3095-2012.The seasonal ranking of PM_(2.5)concentration was in the order of winter>spring>summer>autumn.The annual averaged WSIIs was 24.37±11.54μg/m^(3).The relative contribution of WSIIs to PM_(2.5)increased markedly in winter(56.24%).NH_(4)^(+),NO_(3)^(-),and Cl-showed significant increases in winter,indicating the important influences from combustion emissions,vehicle emissions,and secondary sources.Sulfur oxidation rate(SOR)and nitrogen oxidation rate(NOR)analysis revealed that NOR(0.14±0.07)was lower than SOR(0.40±0.10),indicating a higher secondary conversion rate of SO_(2) under the same atmospheric background.Seasonal disparity was found between SOR and NOR,indicating different dominant factors which affected the sulfate and nitrate formation,with SOR influenced by relative humidity and NOR by NH_(4)^(+)concentration and surrounding traffic sources.We conducted further analysis of characteristics of chemical compositions in different phases.From clean to pollution phase,SOR and NOR rose to a certain extent,suggesting a higher conversion rate of SO_(2)and NOx during pollut

关 键 词：PM_(2.5) 水溶性离子 污染特征 来源分析 常州 

分 类 号：X51[环境科学与工程—环境工程]