沙尘过程中汾渭平原气溶胶化学组分及含水量的演变特征研究  

Evolution Characteristics of Aerosol Chemical Components and Water Content During Sandstorms in the Fenwei Plain

作　　者：刁一伟 杨孟 沈利娟 王红磊[4] 刘焕武 刘诗云 赵天良[4] DIAO Yiwei;YANG Meng;SHEN Lijuan;WANG Honglei;LIU Huanwu;LIU Shiyun;ZHAO Tianliang(Key Laboratory of Ecosystem Carbon Source and Sink,China Meteorological Administration,Wuxi University,Wuxi 214105,China;School of Atmosphere and Remote Sensing,Wuxi University,Wuxi 214105,China;School of Environmental Engineering,Wuxi University,Wuxi 214105,China;Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,China;Xi′an Environmental Monitoring Station,Xi′an 710119,China;Clear Science&Technology Co.,Ltd.,Beijing 100029,China)

机构地区：[1]无锡学院,中国气象局生态系统碳源汇重点开放实验室,江苏无锡214105 [2]无锡学院大气与遥感学院,江苏无锡214105 [3]无锡学院环境工程学院,江苏无锡214105 [4]南京信息工程大学,中国气象局气溶胶-云-降水重点开放实验室,江苏南京210044 [5]西安市环境监测站,陕西西安710119 [6]中科三清科技有限公司,北京100029

出　　处：《环境科学研究》2023年第9期1654-1664,共11页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2022YFC3701204);国家自然科学基金项目(No.42275196);无锡学院引进人才科研启动专项经费(No.2023r035)。

摘　　要：为研究沙尘过程对下游城市地区空气质量的影响,本文基于2021年3月10日—4月6日气溶胶化学组分和气象要素的在线观测数据,结合MODIS卫星遥感AOD(Aerosol Optical Depth)数据、MERRA 2再分析数据和环境六要素数据,探讨了汾渭平原两次沙尘过程和一次扬尘过程中气溶胶化学组分的演变特征,使用ISORRPIAⅡ模式计算了气溶胶含水量和pH,分析了其变化特征.结果表明:①沙尘1(2021年3月16日00:00—21日07:00)、扬尘(3月21日08:00—28日14:00)和沙尘2(3月28日15:00—31日21:00)期间,西安市PM10平均浓度分别为309.5、168.3和472.2μg/m^(3),分别是沙尘前(3月10日00:00—15日22:00)的2.7、1.5和4.1倍.②两次沙尘和扬尘均起源于内蒙古自治区阿拉善盟以及甘肃省酒泉市—张掖市—金昌市一带,但由于传输路径存在显著差异,导致对地面PM_(2.5)浓度的影响不同,沙尘1、扬尘和沙尘2期间PM_(2.5)浓度分别是沙尘前的1.2、1.1和2.5倍.③沙尘和扬尘过程中PM_(2.5)中水溶性离子浓度占比均减小,沙尘1、扬尘和沙尘2中水溶性离子占比分别为45.8%、37.9%和14.8%.在不同阶段PM_(2.5)中水溶性离子占比最高的均为NO_(3)^(−),范围为24.6%(沙尘2)~38.7%(沙尘前);其次是NH4+,占比在19.1%(沙尘前)~22.3%(沙尘2)之间.沙尘过程对SO_(2)转化生成SO_(4)^(2−)的影响要弱于对NO_(2)转化生成NO_(3)^(−)的影响.④沙尘1过程中POC(一次有机碳)占比最高为49.0%,但在扬尘和沙尘2过程中POC占比均较低,分别为42.3%和41.2%,略低于沙尘前.⑤沙尘1、扬尘和沙尘2过程中气溶胶含水量均显著降低,分别为沙尘前的29.9%、43.7%和6.2%.⑥沙尘过程使得水溶性离子中阳离子含量增加,使得气溶胶碱性增强.沙尘1和沙尘2过程中pH分别为6.7和6.5,高于沙尘前(6.2).研究显示,沙尘传输对汾渭平原城市大气中PM_(2.5)化学组分影响较大,显著降低了气溶胶的含水量,增加了气溶胶的pH,导致气溶胶的�Repeatedly occurring sandstorms represent a significant concern in northern China because of their related hazards since particulate matter has harmful impacts on air quality in leeward cities.From March to April 2021,two sandstorms and one dust event(SDS)occurred in the Fenwei Plain.The spatial-temporal variation of aerosol chemical components was studied using simultaneous on-line ambient ions monitor,OC/EC online analyzer,weather and environmental data.The spatial distribution and transport of the sandstorms was represented by the Moderate Resolution Imaging Spectroradiometer(MODIS)Collection 6.1(C6.1)aerosol optical depth(AOD)product sand Modern-Era Retrospective Analysis for Research and Applications,Version 2(MERRA 2)reanalysis datasets.Additionally,the ISORROPIAⅡmodel was used to calculate aerosol water content and pH.The results showed that during sandstorm 1(00:00,March 16th-07:00,March 21st),dust(08:00,March 21st-14:00,March 28th)and sandstorm 2(15:00,March 28 th-21:00,March 31st),the average PM10 concentration in Xi´an City reached 309.5,168.3 and 472.2μg/m^(3),respectively,which was 2.7,1.5 and 4.1 times higher than that before the sandstorm(00:00,March 10th-22:00,March 15^(th)).The SDS events originated from Alxa League in Inner Mongolia and Jiuquan-Zhangye-Jinchang in Gansu Province,and experienced different transport pathways before reaching the Fenwei Plain,therefor the contribution of SDS to the surface PM_(2.5)concentrations showed significant difference.PM_(2.5)concentration increased by 2.5 times during sandstorm 2 compared with that before sandstorm,followed by the concentration increase in sandstorm 1(1.2 times)and dust event(1.1 times).The content of water-soluble ions in PM_(2.5)decreased during the SDS events,accounting for 45.8%,37.9%and 14.8%of PM_(2.5)in sandstorm 1,dust and sandstorm 2,respectively.Among the water-soluble ions,NO_(3)^(−)had the largest proportion in all SDS events,accounting for 24.6%(sandstorm 2)-38.7%(before sandstorm),followed by NH4+,accounting for 19.1%(bef

关 键 词：沙尘 汾渭平原 水溶性离子 含碳气溶胶 气溶胶含水量 pH 

分 类 号：X51[环境科学与工程—环境工程]