中文关键词天津挥发性有机物(VOCs)臭氧生成潜势(OFP)SOA生成潜势污染来源 英文关键词Tianjinvolatile organic compoundsozone formation potentialSOA formation potentialsource apportionment

作者	单位	E-mail
高璟赟	天津市生态环境监测中心, 天津 300191	Aileen_jing@126.com
肖致美	天津市生态环境监测中心, 天津 300191
徐虹	天津市生态环境监测中心, 天津 300191
李立伟	天津市生态环境监测中心, 天津 300191
李鹏	天津市生态环境监测中心, 天津 300191
唐邈	天津市生态环境监测中心, 天津 300191	tangmiao32@163.com
杨宁	天津市生态环境监测中心, 天津 300191
李源	天津市生态环境监测中心, 天津 300191
毕温凯	天津市生态环境监测中心, 天津 300191
陈魁	天津市生态环境监测中心, 天津 300191	kuichen@126.com

中文摘要 为了解天津市环境空气挥发性有机物（VOCs）污染特征及来源，基于2019年城区点位高时间分辨率在线监测数据，对天津市VOCs浓度水平、化学组成及来源进行分析.结果表明，2019年天津市VOCs年均浓度为48.9 μg·m^-3，不同季节浓度水平依次为：冬季（66.9 μg·m^-3） > 秋季（47.9 μg·m^-3） > 夏季（42.0 μg·m^-3） > 春季（34.6 μg·m^-3）.化学组成包括烷烃、芳香烃、烯烃和炔烃，年均浓度占比分别为：65.0%、17.4%、14.6%和3.0%，其中烷烃、芳香烃和炔烃占比分别在秋季、夏季和冬季最高，烯烃占比在夏季和冬季均较高.春夏季烷烃、烯烃、芳香烃和炔烃的臭氧生成潜势贡献分别为：16.9%、48.6%、33.5%和1.0%，乙烯、丙烯、间/对-二甲苯、1，2，3-三甲苯、甲苯、异戊二烯、反-2-丁烯、顺-2-戊烯、邻-二甲苯和间-乙基甲苯的臭氧生成潜势较高；秋冬季芳香烃对二次有机气溶胶（SOA）生成潜势贡献高达91.5%，邻-二甲苯、甲苯、间/对-二甲苯、乙苯、邻-乙基甲苯和苯是主要贡献物种.PMF解析结果表明，春夏季VOCs主要来源分别为：机动车排放源、LPG/NG和汽油挥发源、溶剂使用源、石化工业源、燃烧源和天然源，贡献率分别为：29.2%、19.9%、16.4%、10.3%、7.3%和6.6%；秋冬季VOCs主要来源分别为：LPG/NG和汽油挥发源、机动车排放源、燃烧源、溶剂使用源和石化工业源，贡献率分别为：32.4%、21.9%、18.5%、13.3%和8.4%.与春夏季相比，秋冬季VOCs来源中LPG/NG和燃烧源贡献率分别显著上升62.8%和153.4%，其他源贡献率下降18.4%~25.0%.结合解析得到的各源类成分谱结果，春夏季石化工业源和溶剂使用源排放以烯烃和芳香烃为主，为臭氧防控重点管控对象；秋冬季燃烧源和溶剂使用源排放芳香烃类物质较多，为SOA重点防控源. 英文摘要 The characterization and source apportionment of atmospheric volatile organic compounds (VOCs) in Tianjin in 2019 were investigated based on high-resolution online monitoring data observed at an urban site in Tianjin. The results showed that the average annual concentration of VOCs was 48.9 μg·m^-3, and seasonal concentrations followed with winter (66.9 μg·m^-3) > autumn (47.9 μg·m^-3) > summer (42.0 μg·m^-3) > spring (34.6 μg·m^-3). The chemical compositions of the VOCs were alkanes, aromatics, alkenes, and alkynes, which accounted for 65.0%, 17.4%, 14.6%, and 3.0% of the VOCs concentrations on average, respectively. The proportion of alkanes, aromatics, and alkynes was the highest in autumn, summer, and winter, respectively, while a higher alkenes proportion was observed in summer and winter. The ozone formation potential contribution of alkanes, alkenes, aromatics, and alkynes in spring and summer was 16.9%, 48.6%, 33.5%, and 1.0%, respectively, and the species with higher contributions were ethene, propylene, m,p-xylene, 1,2,3-trimethylbenzene, toluene, isoprene, trans-2-butene, cis-2-pentene, o-xylene, and m-ethyltoluene. During autumn and winter, the aromatics contributed as much as 91.5% to the secondary organic aerosol (SOA) formation potential, and o-xylene, toluene, m,p-xylene, ethylbenzene, o-ethyltoluene, and benzene were the main contributing species. Positive matrix factorization was applied to estimate VOCs source contributions, and automobile exhaust, liquefied petroleum gas/natural gas (LPG/NG) and gasoline evaporation, solvent usage, petrochemical industrial emissions, combustion, and natural sources were identified as major sources of VOCs in spring and summer, accounting for 29.2%, 19.9%, 16.4%, 10.3%, 7.3%, and 6.6%, respectively. While in autumn and winter, the contributions of LPG/NG and gasoline evaporation, automobile exhaust, combustion, solvent usage, and petrochemical industrial emissions were 32.4%, 21.9%, 18.5%, 13.3%, and 8.4%, respectively. Compared to the source contributions in spring and summer, a significant increase was observed for LPG/NG and combustion emission of 62.8% and 153.4%, respectively, and other sources decreased by 18.4%-25.0% in autumn and winter. Source composition spectrums showed that the petrochemical industry and solvent usage were the main emission sources of alkenes and aromatics in spring and summer, and combustion and solvent usage were the main emission sources of aromatics in autumn and winter. Thus, focus should be played on the petrochemical industry and solvent usage in spring and summer and on combustion and solvent usage in autumn and winter to further prevent and control ozone and SOA in Tianjin.

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