| Title: | [Characteristics and Sources of VOCs at Different Ozone Concentration Levels in Tianjin] |
| Author(s): | Wang WM; Gao JY; Xiao ZM; Li Y; Bi WK; Li LW; Yang N; Xu H; Kong J; |
| Address: | "School of Environmental Science & Engineering, Tianjin University, Tianjin 300350, China. Tianjin Eco-Environmental Monitoring Center, Tianjin 300191, China" |
| DOI: | 10.13227/j.hjkx.202101129 |
| ISSN/ISBN: | 0250-3301 (Print) 0250-3301 (Linking) |
| Abstract: | "To further study the effect of volatile organic compounds (VOCs) on ozone pollution, the characteristics and sources of VOCs at different ozone (O(3)) concentration levels were analyzed, using high-resolution online monitoring data obtained from Tianjin in the summer of 2019. Results showed that VOCs concentrations were 32.94, 38.10, 42.41, and 47.12 mug .m(-3), when the O(3) concentration levels were categorized as excellent, good, light pollution, and moderate pollution, respectively. VOCs were composed of alkanes, alkenes, alkynes and aromatics, which accounted for 61.72%-63.36%, 14.96%-15.51%, 2.73%-4.13%, and 18.53%-19.10%, respectively, of VOCs concentrations at different O(3) concentration levels. Among them, the proportion of alkanes was slightly higher when O(3) concentration was categorized as good or light pollution, alkenes and alkynes accounted for the highest proportion when O(3) concentration was excellent, and the proportion of aromatics was highest during periods of moderate pollution. The main VOCs species were propane, ethane, ethylene, toluent, n-butane, isopentane, m/p-xylene, propylene, acetylene, n-hexane, isobutene, benzene, n-pentane, isoprene, and 1,2,3-trimethylbenzene. The concentration percentage of isopentane, n-pentane, benzene, ethylene, propylene, n-butane, and isobutane increased gradually as O(3) concentration increased. Significant increases in isoprene and 1,2,3-trimethylbenzene were observed during periods of light and moderate pollution. Alkenes and aromatics had higher ozone formation potential (OFP), and the contribution of alkenes to OFP declined as the O(3) level rose, whereas that of aromatics increased. Ethylene, propylene, m/p-xylene, 1,2,3-trimethylbenzene, toluene, isoprene, trans-2-butene, and cis-2-pentene were the key species for O(3) generation, and the contribution ratio of 1,2,3-trimethylbenzene, isoprene, propylene, and ethylene to OFP increased significantly during light or moderate O(3) pollution. Positive matrix factorization was applied to estimate the source contributions of VOCs. Automobile exhaust, solvent usage, liquefied petroleum gas (LPG)/gasoline evaporation, combustion, petrochemical industrial emissions, natural sources, and other industrial emissions were identified as major sources of VOCs in summer. As O(3) concentration level rose, the contribution percentage of automobile exhaust, LPG/gasoline evaporation, petrochemical industrial emissions, and natural sources increased gradually, whereas the contribution of combustion and other industrial emissions decreased overall. The contribution of solvent usage was lower when O(3) levels indicated light or moderate pollution than when it was good" |
| Keywords: | *Air Pollutants/analysis China Environmental Monitoring *Ozone/analysis Vehicle Emissions/analysis *Volatile Organic Compounds/analysis concentration levels ozone (O3) pollution characterization source apportionment volatile organic compounds (VOCs); |
| Notes: | "MedlineWang, Wen-Mei Gao, Jing-Yun Xiao, Zhi-Mei Li, Yuan Bi, Wen-Kai Li, Li-Wei Yang, Ning Xu, Hong Kong, Jun chi China 2021/07/27 Huan Jing Ke Xue. 2021 Aug 8; 42(8):3585-3594. doi: 10.13227/j.hjkx.202101129" |
