| Title: | Removing the effects of meteorological factors on changes in nitrogen dioxide and ozone concentrations in China from 2013 to 2020 |
| Author(s): | Lin C; Lau AKH; Fung JCH; Song Y; Li Y; Tao M; Lu X; Ma J; Lao XQ; |
| Address: | "Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China; Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, The Hong Kong University of Science and Technology, Hong Kong, China. Electronic address: alau@ust.hk. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, The Hong Kong University of Science and Technology, Hong Kong, China; Department of Mathematics, The Hong Kong University of Science and Technology, Hong Kong, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China; Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China. Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China. Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China. Department of Urban Planning and Design, The University of Hong Kong, Hong Kong, China. Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China" |
| DOI: | 10.1016/j.scitotenv.2021.148575 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Previous studies on long-term ozone (O(3)) variations in China have reported inconsistent conclusions on the role of meteorological factors in controlling said variations. In this study, we used an observation-based decomposition model to conduct an up-to-date investigation of the effects of meteorological factors on the variations in nitrogen dioxide (NO(2)) and O(3) concentrations in China in the summer from 2013 to 2020. The variations in NO(2) and O(3) concentrations after removing the major meteorological effects were then analyzed to improve our understanding of O(3) formation regimes. Ground measurements show that both NO(2) and O(3) concentrations decreased in eastern, central, and southeastern China (e.g., NO(2) and O(3) concentrations in Wuhan reduced by 4.3 and 6.2 ppb, respectively), which was not anticipated. Analyses of meteorological effects showed that reduced wind strength, decreased temperature, and increased relative humidity significantly reduced O(3) concentrations in eastern and central China (e.g., by 10.5 ppb in Wuhan). After removing the major meteorological effects, the O(3) trends were reversed in eastern and central China (e.g., increased by 4.9 ppb in Wuhan). The contrasting trends in NO(2) and O(3) concentrations suggest that their O(3) formations were sensitive to volatile organic compounds (VOC-limited regime). In southeastern China, both NO(2) and O(3) concentrations decreased, implying that the O(3) formation regimes changed to mixed sensitive or nitrogen oxide-limited (NO(x)-limited) regimes. The meteorological effects varied by region and may play a dominant role in controlling the long-term O(3) variation. Our results indicate that the attribution of O(3) variation to emission control without accounting for meteorological effects can be misleading" |
| Keywords: | *Air Pollutants/analysis China Environmental Monitoring Meteorological Concepts Nitrogen Dioxide/analysis *Ozone/analysis Clean Air Action Plan Emission Meteorology Nitrogen dioxide Ozone; |
| Notes: | "MedlineLin, Changqing Lau, Alexis K H Fung, Jimmy C H Song, Yushan Li, Ying Tao, Minghui Lu, Xingcheng Ma, Jun Lao, Xiang Qian eng Netherlands 2021/06/28 Sci Total Environ. 2021 Nov 1; 793:148575. doi: 10.1016/j.scitotenv.2021.148575. Epub 2021 Jun 19" |
