« Previous AbstractOptimization of volatile markers of lung cancer to exclude interferences of non-malignant disease    Next AbstractSeasonal Variation in Essential Oils Composition and the Biological and Pharmaceutical Protective Effects of Mentha longifolia Leaves Grown in Tunisia »

Sci Total Environ

Title:		"Source apportionment and ozone formation mechanism of VOCs considering photochemical loss in Guangzhou, China"
Author(s):		Zou Y; Yan XL; Flores RM; Zhang LY; Yang SP; Fan LY; Deng T; Deng XJ; Ye DQ;
Address:		"School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Institute of Tropical and Marine Meteorology, China Meteorological Administration (CMA), Guangzhou 510640, China. State Key Laboratory of Severe Weather & Institute of Tibetan Plateau Meteorology, Chinese Academy of Meteorological Sciences, Beijing, China. Marmara University, Department of Environmental Engineering, Istanbul, Turkey. Institute of Tropical and Marine Meteorology, China Meteorological Administration (CMA), Guangzhou 510640, China. School of Environment and Energy, South China University of Technology, Guangzhou 510006, China. School of Environment and Energy, South China University of Technology, Guangzhou 510006, China. Electronic address: cedqye@scut.edu.cn"
Journal Title:		Sci Total Environ
Year:		2023
Volume:		20230809
Issue:
Page Number:		166191 -
DOI:		10.1016/j.scitotenv.2023.166191
ISSN/ISBN:		1879-1026 (Electronic) 0048-9697 (Linking)
Abstract:		"Understanding the sources and impact of volatile organic compounds (VOCs) on ozone formation is challenging when the traditional method does not account for their photochemical loss. In this study, online monitoring of 56 VOCs was carried out in summer and autumn during high ozone pollution episodes. The photochemical age method was used to evaluate the atmospheric chemical loss of VOCs and to analyze the effects on characteristics, sources, and ozone formation of VOC components. The initial concentrations during daytime were 5.12 ppbv and 4.49 ppbv higher than the observed concentrations in the summer and autumn, respectively. The positive matrix factorization (PMF) model identified 5 major emission sources. However, the omission of the chemical loss of VOCs led to underestimating the contributions of sources associated with highly reactive VOC components, such as those produced by biogenic emissions and solvent usage. Conversely it resulted in overestimating the contributions from VOC components with lower chemical activity such as liquefied petroleum gas (LPG) usage, vehicle emissions, and gasoline evaporation. Furthermore, the estimation of ozone formation may be underestimated when the atmospheric photochemical loss is not taken into account. The ozone formation potential (OFP) method and propylene-equivalent concentration method both underestimated ozone formation by 53.24 ppbv and 47.25 ppbc, respectively, in the summer, and by 40.34 ppbv and 26.37 ppbc, respectively, in the autumn. The determination of the ozone formation regime based on VOC chemical loss was more acceptable. In the summer, the ozone formation regime changed from the VOC-limited regime to the VOC-NOx transition regime, while in the autumn, the ozone formation regime changed from the strong VOC-limited regime to the weak VOC-limited regime. To obtain more thorough and precise conclusions, further monitoring and analysis studies will be conducted in the near future on a wider variety of VOC species such as oxygenated VOCs (OVOCs)"
Keywords:		Megacity Ozone pollution Photochemical age Volatile organic compounds (VOCs);
Notes:		"PublisherZou, Y Yan, X L Flores, R M Zhang, L Y Yang, S P Fan, L Y Deng, T Deng, X J Ye, D Q eng Netherlands 2023/08/12 Sci Total Environ. 2023 Aug 9; 903:166191. doi: 10.1016/j.scitotenv.2023.166191"