夏秋季宁波市气态元素汞(GEM)污染特征及潜在源区贡献分析  

Pollution Characteristics and Potential Source Contributions of Gaseous Elemental Mercury(GEM) During Summer and Autumn in Ningbo City

作　　者：易辉 林佳梅 蔡秋亮 王克强 陈进生[1,3] 佟磊[1,3,4] 李建荣 肖航[1,3,4] YI Hui;LIN Jia-mei;CAI Qiu-liang;WANG Ke-qiang;CHEN Jin-sheng;TONG Lei;LI Jian-rong;XIAO Hang(Key Laboratory of Urban Environment and Health,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen 361021,China;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Excellence in Regional Atmospheric Environment,Chinese Academy of Sciences,Xiamen 361021,China;Ningbo Urban Environment Observation and Research Station,Chinese Academy of Sciences,Ningbo 315800,China)

机构地区：[1]中国科学院城市环境研究所城市环境与健康重点实验室,厦门361021 [2]中国科学院大学,北京100049 [3]中国科学院区域大气环境研究卓越创新中心,厦门361021 [4]中国科学院宁波城市环境观测研究站,宁波315800

出　　处：《环境科学》2020年第1期65-74,共10页Environmental Science

基　　金：国家自然科学基金项目(U1405235)

摘　　要：气态元素汞(gaseous elemental mercury,GEM)是普遍存在于大气中的对生物体有害的重金属元素其化学性质稳定,在大气中停留时间长,可随气团长距离输送属于全球性污染物.本研究于2017年夏秋季对宁波市大气GEM、常规污染物和气象参数进行综合观测,研究沿海地区GEM受人为源和自然源共同作用下的迁移转化规律及潜在源贡献来源.结果表明:①观测期间大气GEM的平均质量浓度为(2.32±0.90) ng·m-3,变化范围为0.97~10.95 ng·m-3,且夏季低于秋季.②GEM、O3和GOM在夏季、秋季、晴天和阴雨天的日内浓度变化表明,高浓度的O3和强烈的光照可加速GEM发生光化学反应,GEM在晴天的光化学氧化强度高于阴雨天.③相关性分析表明,GEM与PM2.5(R=0.65,P<0.01)、PM10(R=0.47,P<0.01)、NO2(R=0.46,P<0.01)和CO(R=0.57,P<0.01)呈显著正相关关系,其来源与化石燃料等物质燃烧有关.④O3等光化学氧化剂的浓度、GEM在颗粒物上的气粒分配及PM2.5、水汽和NO2的消光效应,可对GEM光化学氧化速率产生重要影响.⑤潜在源贡献分析(potential source contribution function analysis,PSCF)结果表明夏季浙江省北部(包含宁波市)、西北部,安徽省南部和江西省大部分地区构成一个三角形区域是NBUEORS大气GEM的潜在源贡献区域,且本地源、区域源和长距离源输送对GEM污染均具有重要影响.秋季的潜在源贡献区域主要为浙江省北部区域,范围小于夏季.GEM主要来自本地源和区域源输送影响.因此,针对大气GEM污染的控制,需要跨省的区域联防联控,综合治理,方可有效减轻大气汞的污染.Gaseous elemental mercury(GEM) is commonly known as a hazardous heavy metal in the atmosphere and is harmful to living organisms.GEM is chemically stable and has a long residence time in the atmosphere;hence,it can be transported over long distances with air masses and is regarded as a global pollutant.We study the transportation and transformation mechanisms of GEM and its potential anthropogenic and natural contribution sources.GEM,conventional atmospheric pollutants,and meteorological parameters were monitored at a coastal site in Ningbo during the summer and autumn of 2017.The results were as follows.①The concentrations of GEM ranged from 0.97-10.95 ng·m-3 and the mean and standard deviation(SD) were(2.32±0.90) ng·m-3,whereby the mean summer concentration was lower than the mean autumn concentration.②The diurnal variations of GEM,ozone(03),and gaseous oxidized mercury(GOM) during summer/autumn and sunny/rainy days suggest that higher levels of 03 and that strong solar radiation accounted for the rapid photochemical oxidation of GEM.The intensity of oxidation on sunny days was higher than that on rainy days.③Correlation analysis showed that GEM was significantly positively correlated with PM2.5(R=0.65,P <0.01),PM10(R=0.47,P<0.01),NO2(R=0.46,P <0.01),and CO(R=0.57,P <0.01).Local and regional sources of GEM were mainly related to fossil fuel combustion.④The photochemical oxidation rate of GEM was influenced by the concentrations of oxidants(e.g.,03),gasparticle partitioning between GEM and particles,and light extinction effects of PM2.5,water vapor,and NO2.⑤Potential source contribution analysis(PSCF) indicated that the northwestern Zhejiang Province(including Ningbo City),the southern Anhui Province,and most of Jiangxi Province constitute a triangular area that is a potential source contribution to NBUEORS atmospheric GEM pollution during the summer.Local,regional,and long-range sources all had strong impacts on GEM pollution.During the autumn,the potential sources were mainly in the northern Zheji

关 键 词：气态元素汞(GEM) 光化学氧化 空气污染物 相关性分析 潜在源贡献分析(PSCF) 

分 类 号：X513[环境科学与工程—环境工程]