[2019年天津市大气挥发性有机物的特征及来源解析]
[Characterization and Source Apportionment of Atmospheric VOCs in Tianjin in 2019].
作者信息
Gao Jing-Yun, Xiao Zhi-Mei, Xu Hong, Li Li-Wei, Li Peng, Tang Miao, Yang Ning, Li Yuan, Bi Wen-Kai, Chen Kui
机构信息
Tianjin Eco-Environmental Monitoring Center, Tianjin 300191, China.
出版信息
Huan Jing Ke Xue. 2021 Jan 8;42(1):55-64. doi: 10.13227/j.hjkx.202006257.
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, and seasonal concentrations followed with winter (66.9 μg·m) > autumn (47.9 μg·m) > summer (42.0 μg·m) > spring (34.6 μg·m). 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, ,-xylene, 1,2,3-trimethylbenzene, toluene, isoprene, trans-2-butene, cis-2-pentene, -xylene, and -ethyltoluene. During autumn and winter, the aromatics contributed as much as 91.5% to the secondary organic aerosol (SOA) formation potential, and -xylene, toluene, ,-xylene, ethylbenzene, -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.
基于在天津某城市站点观测到的高分辨率在线监测数据，对2019年天津市大气挥发性有机化合物（VOCs）的特征及来源进行了研究。结果表明，VOCs的年均浓度为48.9 μg·m³，季节浓度顺序为冬季（66.9 μg·m³）＞秋季（47.9 μg·m³）＞夏季（42.0 μg·m³）＞春季（34.6 μg·m³）。VOCs的化学组成包括烷烃、芳烃、烯烃和炔烃，它们分别平均占VOCs浓度的65.0%、17.4%、14.6%和3.0%。烷烃、芳烃和炔烃的占比分别在秋季、夏季和冬季最高，而夏季和冬季的烯烃占比较高。春季和夏季，烷烃、烯烃、芳烃和炔烃对臭氧生成潜势的贡献分别为16.9%、48.6%、33.5%和1.0%，贡献较高的物种有乙烯、丙烯、间二甲苯、1,2,3 - 三甲基苯、甲苯、异戊二烯、反 - 2 - 丁烯、顺 - 2 - 戊烯、邻二甲苯和乙苯。在秋季和冬季，芳烃对二次有机气溶胶（SOA）生成潜势的贡献高达91.5%，间二甲苯、甲苯、对二甲苯、乙苯、邻乙甲苯和苯是主要贡献物种。应用正定矩阵因子分解法估算VOCs的来源贡献，汽车尾气、液化石油气/天然气（LPG/NG）和汽油蒸发、溶剂使用、石化工业排放、燃烧和天然源被确定为春季和夏季VOCs的主要来源，分别占29.2%、19.9%、16.4%、10.3%、7.3%和6.6%。而在秋季和冬季，LPG/NG和汽油蒸发、汽车尾气、燃烧、溶剂使用和石化工业排放的贡献分别为32.4%、21.9%、18.5%、13.3%和8.4%。与春季和夏季的来源贡献相比，秋季和冬季LPG/NG和燃烧排放分别显著增加了62.8%和153.4%，其他来源减少了18.4% - 25.0%。源成分谱表明，石化行业和溶剂使用是春季和夏季烯烃和芳烃的主要排放源，燃烧和溶剂使用是秋季和冬季芳烃的主要排放源。因此，应重点关注春季和夏季的石化行业和溶剂使用以及秋季和冬季的燃烧和溶剂使用，以进一步防控天津的臭氧和SOA。
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