南京北郊大气气溶胶中水溶性有机碳(WSOC)的污染特征  

Characteristics of water-soluble organic carbon(WSOC) in atmospheric particulate matter at northern suburb of Nanjing

作　　者：吴丹[1,2] 沈开源 盖鑫磊[1,2] 夏俊荣[3] 刘刚[1,2] 李凤英[1,2] 杨孟[1,2] WU Dan;SHEN Kai-yuan;GE Xin-lei;XIA Jun-rong;LIU Gang;LI Feng-ying;YANG Meng(Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET),Nanjing University of Information Science and Technology, Nanjing 210044, China;Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science and Technology,Nanjing 210044, China;Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing 210044, China)

机构地区：[1]南京信息工程大学江苏省大气环境与装备技术协同创新中心,江苏南京210004 [2]南京信息工程大学江苏省大气环境监测与污染控制高技术研究重点实验室,江苏南京210044 [3]中国气象局气溶胶与云降水重点开放实验室,江苏南京210044

出　　处：《中国环境科学》2017年第9期3237-3246,共10页China Environmental Science

基　　金：江苏省自然科学基金项目(BK20130998);国家自然科学基金项目(41301581;91544220);南京信息工程大学基金预研项目(2014x003);河北省气象与生态环境重点实验室开放研究基金(Z201607H)

摘　　要：对南京北郊2014年1~11月的大气气溶胶进行采样分析,研究了其中水溶性有机碳(WSOC)的污染特征.WSOC在PM_(2.5),PM_10和TSP中的年平均浓度分别为5.90±3.38、6.93±3.79、7.34±3.91μg/m^3,80%以上的WSOC集中在PM_(2.5)中.PM_(2.5)中WSOC冬季浓度最高,夏季浓度次之,与冬夏季较强的二次转化过程有关;春季粗粒径段浓度较高,受到土壤来源颗粒物的影响;秋季浓度最低.春秋季PM_(2.5)中WSOC浓度夜晚高于白天,受夜间不利扩散条件的影响较大;但冬夏季却是白天高于夜晚,与白天较强的光化学反应有关.降水对各个粒径的WSOC都有清除作用,对PM_(2.5)的清除效率最高;四个季节比较,夏季清除效率最高,达到54.9%.霾发生时,随着霾污染等级的加重,PM_(2.5)中WSOC浓度逐渐增加,从非霾天的3.84μg/m^3升高到重度霾天的11.23μg/m^3,增加了近4倍,在细粒子中的比例也增大,霾天稳定的天气条件有利于二次有机污染物的生成.The atmospheric particles collected during January to November2014at a northern suburban site of Nanjingwas analyzed and focused on the characterization of water-soluble organic carbon(WSOC)in the samples.The annualmean concentrations of WSOC in PM2.5,PM10and TSP were determined to be5.90±3.38,6.93±3.79,7.34±3.91μg/m3respectively,and more than80%of WSOC was concentrated in PM2.5samples.The WSOC concentration in PM2.5washighest in winter following by summer,which was likely related to the strong secondary production during these twoseasons;the WSOC concentration was relatively higher in coarse particles during spring,likely due to influences fromsoil-derived particles;in autumn,the WSOC concentration was the lowest.During spring and autumn,it was also foundthat the PM2.5WSOC concentration was higher during nighttime,probably owing to the atmospheric conditions duringnighttime unfavorable for pollutant dispersion;on the other hand,the concentration was higher during daytime in winterand summer,suggesting the stronger photochemical production of WSOC during these two seasons.The scavenging effectdue to precipitation influenced the WSOC concentrations in particles across all size ranges,but was most efficient forPM2.5,which can reach an maximum of54.9%during summer.The PM2.5WSOC concentration also increasedsignificantly with the increase of pollution level,on average nearly4times from3.84μg/m3in non-hazy days to11.23μg/m3in heavily polluted days;the mass fraction of WSOC in fine mode particles increased in hazy days as well,suggesting that stagnant atmospheric conditions during hazy days promoted the formation of secondary organic pollutants.

关 键 词：WSOC 粒径分布 季节变化 昼夜变化 降水清除 霾 

分 类 号：X513[环境科学与工程—环境工程]