第19届亚运会期间杭州市有机气溶胶污染特征  

Chemical characteristics and variations of organic aerosols in Hangzhou during the 19th Asian Games based on online measurements of organic molecular markers

作　　者：朱书慧 来勇 严仁嫦 高雅琴 沈建东 吴宇航 黄聪艳 叶旭红 金嘉佳 林旭 王蕴赟 张天 费罗兰 帅启凡 ZHU Shu-hui;LAI Yong;YAN Ren-chang;GAO Ya-qin;SHEN Jian-dong;WU Yu-hang;HUANG Cong-yan;YE Xu-hong;JIN Jia-jia;LIN Xu;WANG Yun-yun;ZHANG Tian;FEI Luo-lan;SHUAI Qi-fan(State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex,Shanghai Academy of Environmental Sciences,Shanghai 200233,China;Hangzhou Municipal Ecological and Environment Monitoring Center,Hangzhou 310007,China)

机构地区：[1]上海市环境科学研究院,国家环境保护城市大气复合污染成因与防治重点实验室,上海200233 [2]浙江省杭州生态环境监测中心,浙江杭州310007

出　　处：《中国环境科学》2024年第11期5980-5989,共10页China Environmental Science

基　　金：国家重点研发计划(2023YFC3705201);国家自然科学基金资助项目(42307155)。

摘　　要：采用气溶胶在线热脱附(TAG)系统对有机气溶胶(OA)中110种有机分子示踪物浓度进行了在线监测,分析了亚运会前、会期和会后杭州市OA的化学组成变化和污染特征,评估了减排措施对OA一次和二次生成的影响.结果表明,一次来源有机分子示踪物中,指示机动车排放的藿烷浓度降幅最为显著,会期平均浓度较会前下降了32%,其与元素碳(EC)的浓度比值表明,会前和会后OA整体受柴油车排放影响较为显著,会期藿烷与EC浓度比值更接近汽油车排放源谱,表明会期针对柴油车排放的管控措施对降低一次OA浓度成效显著.二次来源有机分子示踪物中,羟基羧酸和二羧酸浓度占比最高,其会期平均浓度较会前分别下降了56%和32%.进一步比较其与OA中其它有机分子示踪物、挥发性有机(VOCs)前体物的小时浓度相关性发现,二羧酸与OA中指示工业源、自然源排放的二次有机气溶胶(SOA)示踪物及其VOCs前体物具有较强的相关性,羟基羧酸仅与OA中苯系物SOA示踪物和蒎烯SOA示踪物具有较好的相关性,表明二羧酸有机分子主要是由工业排放等人为源以及自然源OA和VOCs经过光化学氧化二次生成,羟基羧酸类OA则是由一次或二次OA在颗粒相中进一步氧化生成.会期羟基羧酸和二羧酸类有机分子示踪物及其VOCs前体物浓度的大幅降低,表明针对工业源、移动源等人为源VOCs排放的管控措施对于降低杭州市OA的二次生成也有显著成效.Air quality in Hangzhou was greatly improved during the 19th Asian Games with the implementation of temporary emission control measures.Observation data collected at the Asian Games Core Supersite show that average concentration of PM_(2.5) during the Games declined by 18%and 71%compared with the periods before and after the Games,respectively.Among its major components,organic aerosols(OA)displayed largest decrease in average concentration by 32%.To further understand the chemical characteristics and formation variations of OA brought by emission reductions,a thermal desorption aerosol GC/MS(TAG)online system was adopted in this study to measure hourly concentrations of total 110organic molecular markers in OA at the same site.The results show that hopanes,which are mainly emitted from vehicles,dropped most significantly among primary organic molecular groups with a mass decrease ratio of 32%.The variations ofαβ-norhanpe to EC andαβ-hanpe to EC mass ratios suggest that OA collected at the supersite was more influenced by diesel emissions before and after the Games.While during the Games,their mass ratios were closer to emission inventory obtained from gasoline vehicles,indicating that restriction measures executed in diesel vehicles remarkably lowered the concentration of primary OA.Among secondary organic molecular markers,hydroxyl-carboxylic acids and dicarboxylic acids were the two groups showing highest mass proportions in TAG-measured OA.Their average concentrations also decreased during the Games by 56%and 32%,respectively.Their correlations with other organic molecular groups in OA as well as volatile organic compounds(VOCs)in the gas phase suggest that dicarboxylic acids were formed via photochemical processing from various particular and gaseous precursors,including naphthalene-related,α-pinene-related,and isoprene-related secondary organic aerosol(SOA)tracers as well as VOC species such as aldehyde ketones,furans,terpenes.While hydroxyl-carboxylic acids were mainly secondarily produced from aromat

关 键 词：有机气溶胶 有机分子示踪物 藿烷 羟基羧酸 二羧酸 

分 类 号：X513[环境科学与工程—环境工程]