Observational and Health Risk-based Methods to Investigate the Effects of Air Pollution Management

The annual assessment of emission control effects on air quality is essential for policy adjustments. However, this assessment is difficult as the inter-annual changes in pollution are impacted by complex meteorological conditions.

In this study, based on our wind-pollution decomposition (WPD) method, which decomposes wind effects (wind-driven) and non-wind effects, the meteorology-pollution decomposition (MPD) method was established, which separates meteorological effects (met-driven) and non-meteorological effects by importing other meteorological parameters, to approximate the emission change effects by the non-meteorological effects. The performance of the MPD method was assessed by comparing the results of the WPD and MPD methods. A case study showed that the met-driven effect from the MPD method is more reasonable than the wind-driven effect from the WPD method in representing complex meteorological influences during ENSO events.

The MPD method was then applied to investigate the cause of unanticipated haze pollution in China during the COVID-19 lockdown period. The results show that the unfavourable meteorological conditions (drastically elevated humidity levels and weakened airflow) overwhelmed the beneficial effects of emission reduction, causing the severe haze pollution.

The MPD method was also applied to separate the effects of meteorological change and emission reduction on NO₂ and O₃ variations over China during lockdown. The drastically enhanced humidity and stagnant airflow substantially increased NO₂ and decreased O₃ concentration in northern China. In contrast, the enhanced temperature and decreased RH greatly increased O₃ concentration in southern China. Compared with meteorological effects, the non-meteorological effects were consistent all over China. The non-meteorological effects decreased NO₂ concentration over China and increased O₃ concentrations in most regions over China. By removing meteorological effect, new NO₂ decreasing center and new O₃ increasing hotspots were observed in northern China. Great anthropogenic effects (e.g., strict control of human activity) were greatly masked by the meteorological effects in northern China. Reduction of NO₂ increased O₃ in most of China, implying that most stations were located in VOC-limited regimes during lockdown period.

In the last part of this thesis, a risk-based method for evaluating the emission control measures is proposed. Observations from ground networks during the lockdowns were used to assess spatial disparity of the ratio of O₃ formation (ROF) for NO₂ reduction in the Greater Bay Area (GBA) of China. The health risk model from Air Quality Health Index (AQHI) system in Hong Kong was adopted to evaluate the risk tradeoffs between NO₂ and O₃. Results show that the levels of O₃ increase and NO₂ reduction were comparable due to high ROF values in urban areas of central GBA. Despite the O₃ increases, the NO_x emission controls reduced the integrated health risk (IHR) of NO₂ and O₃ in most regions of the GBA. When risk factors from the mortality in Canada or the global review were adopted in the risk analyses, the results are extremely encouraging because the controls of NO_x emission reduced the IHR of NO₂ and O₃ almost everywhere in the GBA. The policy of reducing NO_x emission is also consistent with the goal of carbon neutrality due to the reduction of fossil fuel combustion. The health risk isopleth provides a more comprehensive representation of the health effects of control policy than O₃ isopleth. The findings of this study underscore the importance of using a risk-based method to assess the effectiveness of emission control measures and the overall health benefit from NO_x emission controls in the GBA.

Akimoto, H., & Tanimoto, H. (2022). Rethinking of the adverse effects of NOx-control on the reduction of methane and tropospheric ozone – Challenges toward a denitrified society. Atmospheric Environment, 277, 119033. https://doi.org/10.1016/j.atmosenv.2022.119033An, Z., Huang, R.-J., Zhang, R., Tie, X., Li, G., Cao, J., Zhou, W., Shi, Z., Han, Y., Gu, Z., & Ji, Y. (2019). Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes. In Proceedings of the National Academy of Sciences of the United States of America (Vol. 116, Issue 18, pp. 8657–8666). https://doi.org/10.1073/pnas.1900125116Anderson, H., de Leon, A. P., Bland, J., Bower, J., Emberlin, J., & Strachan, D. (1998). Air pollution, pollens, and daily admissions for asthma in London 1987–92. Thorax, 53(10), 842–848.Aw, J., & Kleeman, M. J. (2003). Evaluating the first-order effect of intraannual temperature variability on urban air pollution. In Journal of Geophysical Research-Atmospheres (Vol. 108, Issue D12). https://doi.org/10.1029/2002jd002688Azman, A. S., & Luquero, F. J. (2020). From China: Hope and lessons for COVID-19 control. The Lancet. Infectious Diseases, 20(7), 756–757. https://doi.org/10.1016/S1473-3099(20)30264-4Cairncross, E. K., John, J., & Zunckel, M. (2007). A novel air pollution index based on the relative risk of daily mortality associated with short-term exposure to common air pollutants. Atmospheric Environment, 41(38), 8442–8454. https://doi.org/10.1016/j.atmosenv.2007.07.003Cao, Z., Sheng, L., Liu, Q., Yao, X., & Wang, W. (2015). Interannual increase of regional haze-fog in North China Plain in summer by intensified easterly winds and orographic forcing. In Atmospheric Environment (Vol. 122, pp. 154–162). https://doi.org/10.1016/j.atmosenv.2015.09.042Chen, K., Wang, M., Huang, C., Kinney, P. L., & Anastas, P. T. (2020). Air pollution reduction and mortality benefit during the COVID-19 outbreak in China. The Lancet. Planetary Health, 4(6), e210–e212. https://doi.org/10.1016/S2542-5196(20)30107-8Chen, X., Fan, S., Li, J., Liu, J., Wang, A., & Fong, S. (2008). The typical weather characteristics of the air pollution in Hong Kong area. In Journal of Tropical Meteorology (Vol. 24, Issue 2, pp. 195–199).Chen, X., Wang, X., Huang, J., Zhang, L., Song, F., Mao, H., Chen, K., Chen, J., Liu, Y., Jiang, G., Dong, G., Bai, Z., & Tang, N. (2017). Nonmalignant respiratory mortality and long-term exposure to PM10 and SO2: A 12-year cohort study in northern China. Environmental Pollution, 231, 761–767. https://doi.org/10.1016/j.envpol.2017.08.085Chen, Y., Zhang, S., Peng, C., Shi, G., Tian, M., Huang, R.-J., Guo, D., Wang, H., Yao, X., & Yang, F. (2020). Impact of the COVID-19 pandemic and control measures on air quality and aerosol light absorption in Southwestern China. Science of the Total Environment, 749, 141419. https://doi.org/10.1016/j.scitotenv.2020.141419Chen, Z., Cai, J., Gao, B., Xu, B., Dai, S., He, B., & Xie, X. (2017). Detecting the causality influence of individual meteorological factors on local PM2.5 concentration in the Jing-Jin-Ji region. In Scientific Reports (Vol. 7). https://doi.org/10.1038/srep40735Chen, Z., Chen, D., Kwan, M.-P., Chen, B., Gao, B., Zhuang, Y., Li, R., & Xu, B. (2019). The control of anthropogenic emissions contributed to 80% of the decrease in PM2.5 concentrations in Beijing from 2013 to 2017. In Atmospheric Chemistry and Physics (Vol. 19, Issue 21, pp. 13519–13533). https://doi.org/10.5194/acp-19-13519-2019Chen, Z. Y., Xie, X. M., Cai, J., Chen, D. L., Gao, B. B., He, B., Cheng, N. L., & Xu, B. (2018). Understanding meteorological influences on PM2.5 concentrations across China: A temporal and spatial perspective. In Atmospheric Chemistry and Physics (Vol. 18, Issue 8, pp. 5343–5358). https://doi.org/10.5194/acp-18-5343-2018Cheng, X., Zhao, T., Gong, S., Xu, X., Han, Y., Yin, Y., Tang, L., He, H., & He, J. (2016). Implications of East Asian summer and winter monsoons for interannual aerosol variations over central-eastern China. In Atmospheric Environment (Vol. 129, pp. 218–228). https://doi.org/10.1016/j.atmosenv.2016.01.037China Ministry of Environmental Protection. (2013). China Environment Status Bulletin 2013.China’s State Council. (2013). The Action Plan for Air Pollution Prevention and Control. http://www.gov.cn/zwgk/2013-09/12/content_2486773.htmChu, B., Zhang, S., Liu, J., Ma, Q., & He, H. (2021). Significant concurrent decrease in PM2.5 and NO2 concentrations in China during COVID-19 epidemic. Journal of Environmental Sciences, 99, 346–353. https://doi.org/10.1016/j.jes.2020.06.031Cohen, A. J., Brauer, M., Burnett, R., Anderson, H. R., Frostad, J., Estep, K., Balakrishnan, K., Brunekreef, B., Dandona, L., Dandona, R., Feigin, V., Freedman, G., Hubbell, B., Jobling, A., Kan, H., Knibbs, L., Liu, Y., Martin, R., Morawska, L., … Forouzanfar, M. H. (2017). Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: An analysis of data from the Global Burden of Diseases Study 2015. In Lancet (Vol. 389, Issue 10082, pp. 1907–1918). https://doi.org/10.1016/s0140-6736(17)30505-6Dai, Q., Liu, B., Bi, X., Wu, J., Liang, D., Zhang, Y., Feng, Y., & Hopke, P. K. (2020). Dispersion Normalized PMF Provides Insights into the Significant Changes in Source Contributions to PM2.5 after the COVID-19 Outbreak. Environmental Science & Technology, 54(16), 9917–9927. https://doi.org/10.1021/acs.est.0c02776Dawson, J. P., Adams, P. J., & Pandis, S. N. (2007). Sensitivity of PM2.5 to climate in the Eastern US: a modeling case study. In Atmospheric Chemistry and Physics (Vol. 7, Issue 16, pp. 4295–4309). https://doi.org/10.5194/acp-7-4295-2007de Foy, B., Brune, W. H., & Schauer, J. J. (2020). Changes in ozone photochemical regime in Fresno, California from 1994 to 2018 deduced from changes in the weekend effect. Environmental Pollution, 263, 114380. https://doi.org/10.1016/j.envpol.2020.114380Ding, A. J., Fu, C. B., Yang, X. Q., Sun, J. N., Zheng, L. F., Xie, Y. N., Herrmann, E., Nie, W., Petäjä, T., Kerminen, V.-M., & Kulmala, M. (2013). Ozone and fine particle in the western Yangtze River Delta: An overview of 1 yr data at the SORPES station. Atmospheric Chemistry and Physics, 13(11), 5813–5830. https://doi.org/10.5194/acp-13-5813-2013Doumbia, T., Granier, C., Elguindi, N., Bouarar, I., Darras, S., Brasseur, G., Gaubert, B., Liu, Y., Shi, X., Stavrakou, T., Tilmes, S., Lacey, F., Deroubaix, A., & Wang, T. (2021). Changes in global air pollutant emissions during the COVID-19 pandemic: A dataset for atmospheric modeling. Earth System Science Data, 13(8), 4191–4206. https://doi.org/10.5194/essd-13-4191-2021Field, C. B. (2014). Climate change 2014–Impacts, adaptation and vulnerability: Regional aspects. Cambridge University Press.Franchini, M., & Mannucci, P. M. (2012). Air pollution and cardiovascular disease. Thrombosis Research, 129(3), 230–234. https://doi.org/10.1016/j.thromres.2011.10.030Gao, C., Yin, H., Ai, N., & Huang, Z. (2009). Historical Analysis of SO2 Pollution Control Policies in China. Environmental Management, 43(3), 447–457. https://doi.org/10.1007/s00267-008-9252-xGery, M., & Crouse, R. (1991). User’s guide for executing OZIPR.Grange, S. K., Carslaw, D. C., Lewis, A. C., Boleti, E., & Hueglin, C. (2018). Random forest meteorological normalisation models for Swiss PM10 trend analysis. Atmospheric Chemistry and Physics, 18(9), 6223–6239. https://doi.org/10.5194/acp-18-6223-2018Gui, K., Che, H., Wang, Y., Wang, H., Zhang, L., Zhao, H., Zheng, Y., Sun, T., & Zhang, X. (2019). Satellite-derived PM2.5 concentration trends over Eastern China from 1998 to 2016: Relationships to emissions and meteorological parameters. Environmental Pollution, 247, 1125–1133. https://doi.org/10.1016/j.envpol.2019.01.056Guo, H., Liu, J., & Wei, J. (2021). Ambient Ozone, PM1 and Female Lung Cancer Incidence in 436 Chinese Counties. International Journal of Environmental Research and Public Health, 18(19), 10386. https://doi.org/10.3390/ijerph181910386Hafner, S. D., Howard, C., Muck, R. E., Franco, R. B., Montes, F., Green, P. G., Mitloehner, F., Trabue, S. L., & Rotz, C. A. (2013). Emission of volatile organic compounds from silage: Compounds, sources, and implications. Atmospheric Environment, 77, 827–839. https://doi.org/10.1016/j.atmosenv.2013.04.076He, C., Liu, R., Wang, X., Liu, S. C., Zhou, T., & Liao, W. (2019). How does El Nino-Southern Oscillation modulate the interannual variability of winter haze days over eastern China? In Science of the Total Environment (Vol. 651, pp. 1892–1902). https://doi.org/10.1016/j.scitotenv.2018.10.100He, G., Pan, Y., & Tanaka, T. (2020). The short-term impacts of COVID-19 lockdown on urban air pollution in China. Nature Sustainability, 1–7. https://doi.org/10.1038/s41893-020-0581-yHe, J., Gong, S., Zhou, C., Lu, S., Wu, L., Chen, Y., Yu, Y., Zhao, S., Yu, L., & Yin, C. (2018). Analyses of winter circulation types and their impacts on haze pollution in Beijing. Atmospheric Environment, 192, 94–103. https://doi.org/10.1016/j.atmosenv.2018.08.060Holm, S. M., & Balmes, J. R. (2022). Systematic Review of Ozone Effects on Human Lung Function, 2013 Through 2020. Chest, 161(1), 190–201. https://doi.org/10.1016/j.chest.2021.07.2170Holzworth, G. C. (1964). Estimates of mean maximum mixing depths in the contiguous United States. Mon. Weather Rev., 92(5), 235–242.Hossain, Md. S., Frey, H. C., Louie, P. K. K., & Lau, A. K. H. (2021). Combined effects of increased O3 and reduced NO2 concentrations on short-term air pollution health risks in Hong Kong. Environmental Pollution, 270, 116280. https://doi.org/10.1016/j.envpol.2020.116280Hou, X., Zhu, B., Kumar, K. R., & Lu, W. (2019). Inter-annual variability in fine particulate matter pollution over China during 2013–2018: Role of meteorology. Atmospheric Environment, 214, 116842. https://doi.org/10.1016/j.atmosenv.2019.116842Huang, X., Ding, A., Gao, J., Zheng, B., Zhou, D., Qi, X., Tang, R., Wang, J., Ren, C., Nie, W., Chi, X., Xu, Z., Chen, L., Li, Y., Che, F., Pang, N., Wang, H., Tong, D., Qin, W., … He, K. (2020). Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China. National Science Review. https://doi.org/10.1093/nsr/nwaa137Huang, X.-F., Yu, J. Z., Yuan, Z., Lau, A. K. H., & Louie, P. K. K. (2009). Source analysis of high particulate matter days in Hong Kong. In Atmospheric Environment (Vol. 43, Issue 6, pp. 1196–1203). https://doi.org/10.1016/j.atmosenv.2008.10.013Huangfu, P., & Atkinson, R. (2020). Long-term exposure to NO2 and O3 and all-cause and respiratory mortality: A systematic review and meta-analysis. Environment International, 144, 105998. https://doi.org/10.1016/j.envint.2020.105998Jacob, D. J., & Winner, D. A. (2009). Effect of climate change on air quality. In Atmospheric Environment (Vol. 43, Issue 1, pp. 51–63). https://doi.org/10.1016/j.atmosenv.2008.09.051Jia, H., Huo, J., Fu, Q., Duan, Y., Lin, Y., Jin, X., Hu, X., & Cheng, J. (2020). Insights into chemical composition, abatement mechanisms and regional transport of atmospheric pollutants in the Yangtze River Delta region, China during the COVID-19 outbreak control period. Environmental Pollution, 267, 115612. https://doi.org/10.1016/j.envpol.2020.115612Jiang, L., He, S., Cui, Y., Zhou, H., & Kong, H. (2020). Effects of the socio-economic influencing factors on SO2 pollution in Chinese cities: A spatial econometric analysis based on satellite observed data. Journal of Environmental Management, 268, 110667. https://doi.org/10.1016/j.jenvman.2020.110667Kang, H., Zhu, B., van der A, R. J., Zhu, C., de Leeuw, G., Hou, X., & Gao, J. (2019). Natural and anthropogenic contributions to long-term variations of SO2, NO2, CO, and AOD over East China. Atmospheric Research, 215, 284–293. https://doi.org/10.1016/j.atmosres.2018.09.012Kang, M., Zhang, J., Zhang, H., & Ying, Q. (2021). On the Relevancy of Observed Ozone Increase during COVID-19 Lockdown to Summertime Ozone and PM2.5 Control Policies in China. Environmental Science & Technology Letters, acs.estlett.1c00036. https://doi.org/10.1021/acs.estlett.1c00036Kassomenos, P., Kotroni, V., & Kallos, G. (1995). Analysis of climatological and air quality observations from Greater Athens Area. Atmospheric Environment, 29(24), 3671–3688. https://doi.org/10.1016/1352-2310(94)00358-RKim, M. J., Park, R. J., & Kim, J.-J. (2012). Urban air quality modeling with full O3–NOx–VOC chemistry: Implications for O3 and PM air quality in a street canyon. Atmospheric Environment, 47, 330–340. https://doi.org/10.1016/j.atmosenv.2011.10.059Koch, D., Park, J., & Del Genio, A. (2003). Clouds and sulfate are anticorrelated: A new diagnostic for global sulfur models. In Journal of Geophysical Research-Atmospheres (Vol. 108, Issue D24). https://doi.org/10.1029/2003jd003621Le, T., Wang, Y., Liu, L., Yang, J., Yung, Y. L., Li, G., & Seinfeld, J. H. (2020). Unexpected air pollution with marked emission reductions during the COVID-19 outbreak in China. Science. https://doi.org/10.1126/science.abb7431Lee, K. K., Spath, N., Miller, M. R., Mills, N. L., & Shah, A. S. V. (2020). Short-term exposure to carbon monoxide and myocardial infarction: A systematic review and meta-analysis. Environment International, 143, 105901. https://doi.org/10.1016/j.envint.2020.105901Leung, D. M., Tai, A. P. K., Mickley, L. J., Moch, J. M., van Donkelaar, A., Shen, L., & Martin, R. V. (2018). Synoptic meteorological modes of variability for fine particulate matter (PM2.5) air quality in major metropolitan regions of China. In Atmospheric Chemistry and Physics (Vol. 18, Issue 9, pp. 6733–6748). https://doi.org/10.5194/acp-18-6733-2018Li, K., Jacob, D. J., Liao, H., Shen, L., Zhang, Q., & Bates, K. H. (2019). Anthropogenic drivers of 2013–2017 trends in summer surface ozone in China. Proceedings of the National Academy of Sciences, 116(2), 422–427. https://doi.org/10.1073/pnas.1812168116Li, L., Li, Q., Huang, L., Wang, Q., Zhu, A., Xu, J., Liu, Z., Li, H., Shi, L., Li, R., Azari, M., Wang, Y., Zhang, X., Liu, Z., Zhu, Y., Zhang, K., Xue, S., Ooi, M. C. G., Zhang, D., & Chan, A. (2020). Air quality changes during the COVID-19 lockdown over the Yangtze River Delta Region: An insight into the impact of human activity pattern changes on air pollution variation. Science of The Total Environment, 732, 139282. https://doi.org/10.1016/j.scitotenv.2020.139282Li, L., Lu, C., Chan, P.-W., Lan, Z., Zhang, W., Yang, H., & Wang, H. (2022). Impact of the COVID-19 on the vertical distributions of major pollutants from a tower in the Pearl River Delta. Atmospheric Environment, 276, 119068. https://doi.org/10.1016/j.atmosenv.2022.119068Li, M., Tang, G., Huang, J., Liu, Z., An, J., & Wang, Y. (2015). Characteristics of Winter Atmospheric Mixing Layer Height in Beijing-Tianjin-Hebei Region and Their Relationship with the Atmospheric Pollution. In Environmental Science (Vol. 36, Issue 6, pp. 1935–1943).Li, R., Zhao, Y., Fu, H., Chen, J., Peng, M., & Wang, C. (2021). Substantial changes in gaseous pollutants and chemical compositions in fine particles in the North China Plain during the COVID-19 lockdown period: Anthropogenic vs. meteorological influences. Atmospheric Chemistry and Physics, 21(11), 8677–8692. https://doi.org/10.5194/acp-21-8677-2021Li, Y., Lau, A., Wong, A., & Fung, J. (2014). Decomposition of the wind and nonwind effects on observed year-to-year air quality variation. Journal of Geophysical Research: Atmospheres, 119(10), 6207–6220. https://doi.org/10.1002/2013JD021300Lian, X., Huang, J., Huang, R., Liu, C., Wang, L., & Zhang, T. (2020). Impact of city lockdown on the air quality of COVID-19-hit of Wuhan city. Science of The Total Environment, 742, 140556. https://doi.org/10.1016/j.scitotenv.2020.140556Liao, H., Chen, W.-T., & Seinfeld, J. H. (2006). Role of climate change in global predictions of future tropospheric ozone and aerosols. In Journal of Geophysical Research-Atmospheres (Vol. 111, Issue D12). https://doi.org/10.1029/2005jd006852Lim, C. C., Hayes, R. B., Ahn, J., Shao, Y., Silverman, D. T., Jones, R. R., Garcia, C., Bell, M. L., & Thurston, G. D. (2019). Long-Term Exposure to Ozone and Cause-Specific Mortality Risk in the United States. American Journal of Respiratory and Critical Care Medicine, 200(8), 1022–1031. https://doi.org/10.1164/rccm.201806-1161OCLin, C., Labzovskii, L. D., Leung Mak, H. W., Fung, J. C. H., Lau, A. K. H., Kenea, S. T., Bilal, M., Vande Hey, J. D., Lu, X., & Ma, J. (2020). Observation of PM2.5 using a combination of satellite remote sensing and low-cost sensor network in Siberian urban areas with limited reference monitoring. Atmospheric Environment, 227, 117410. https://doi.org/10.1016/j.atmosenv.2020.117410Lin, C., Lau, A. K. H., Fung, J. C. H., Song, Y., Li, Y., Tao, M., Lu, X., Ma, J., & Lao, X. Q. (2021). Removing the effects of meteorological factors on changes in nitrogen dioxide and ozone concentrations in China from 2013 to 2020. Science of The Total Environment, 793, 148575. https://doi.org/10.1016/j.scitotenv.2021.148575Lin, C., Li, Y., Lau, A. K. H., Li, C., & Fung, J. C. H. (2018). 15-Year PM2.5 Trends in the Pearl River Delta Region and Hong Kong from Satellite Observation. Aerosol and Air Quality Research, 18(9), 2355–2362. https://doi.org/10.4209/aaqr.2017.11.0437Lin, C. Q., Liu, G., Lau, A. K. H., Li, Y., Li, C. C., Fung, J. C. H., & Lao, X. Q. (2018). High-resolution satellite remote sensing of provincial PM2.5 trends in China from 2001 to 2015. Atmospheric Environment, 180, 110–116. https://doi.org/10.1016/j.atmosenv.2018.02.045Lin, J., Lin, C., Tao, M., Ma, J., Fan, L., Xu, R.-A., & Fang, C. (2021). Spatial Disparity of Meteorological Impacts on Carbon Monoxide Pollution in China during the COVID-19 Lockdown Period. ACS Earth and Space Chemistry, 5(10), 2900–2909. https://doi.org/10.1021/acsearthspacechem.1c00251Ling, Z., Huang, T., Zhao, Y., Li, J., Zhang, X., Wang, J., Lian, L., Mao, X., Gao, H., & Ma, J. (2017). OMI-measured increasing SO2 emissions due to energy industry expansion and relocation in northwestern China. Atmospheric Chemistry and Physics, 17(14), 9115–9131. https://doi.org/10.5194/acp-17-9115-2017Liu, H., He, J., Guo, J., Miao, Y., Yin, J., Wang, Y., Xu, H., Liu, H., Yan, Y., Li, Y., & Zhai, P. (2017). The blue skies in Beijing during APEC 2014: A quantitative assessment of emission control efficiency and meteorological influence. Atmospheric Environment, 167, 235–244. https://doi.org/10.1016/j.atmosenv.2017.08.032Liu, L., Zhang, J., Du, R., Teng, X., Hu, R., Yuan, Q., Tang, S., Ren, C., Huang, X., Xu, L., Zhang, Y., Zhang, X., Song, C., Liu, B., Lu, G., Shi, Z., & Li, W. (2021). Chemistry of Atmospheric Fine Particles During the COVID-19 Pandemic in a Megacity of Eastern China. Geophysical Research Letters, 48(2), 2020GL091611. https://doi.org/10.1029/2020GL091611Liu, S., Liu, C., Hu, Q., Su, W., Yang, X., Lin, J., Zhang, C., Xing, C., Ji, X., Tan, W., Liu, H., & Gao, M. (2021). Distinct Regimes of O3 Response to COVID-19 Lockdown in China. Atmosphere, 12(2), 184. https://doi.org/10.3390/atmos12020184Liu, T., Gong, S., He, J., Yu, M., Wang, Q., Li, H., Liu, W., Zhang, J., Li, L., Wang, X., Li, S., Lu, Y., Du, H., Wang, Y., Zhou, C., Liu, H., & Zhao, Q. (2017). Attributions of meteorological and emission factors to the 2015 winter severe haze pollution episodes in China’s Jing-Jin-Ji area. Atmospheric Chemistry and Physics, 17(4), 2971–2980. https://doi.org/10.5194/acp-17-2971-2017Liu, T., Wang, X., Hu, J., Wang, Q., An, J., Gong, K., Sun, J., Li, L., Qin, M., Li, J., Tian, J., Huang, Y., Liao, H., Zhou, M., Hu, Q., Yan, R., Wang, H., & Huang, C. (2020). Driving Forces of Changes in Air Quality during the COVID-19 Lockdown Period in the Yangtze River Delta Region, China. Environmental Science & Technology Letters, 7(11), 779–786. https://doi.org/10.1021/acs.estlett.0c00511Liu, Y., Hong, Y., Fan, Q., Wang, X., Chan, P., Chen, X., Lai, A., Wang, M., & Chen, X. (2017). Source-receptor relationships for PM2.5 during typical pollution episodes in the Pearl River Delta city cluster, China. In Science of the Total Environment (Vol. 596, pp. 194–206). https://doi.org/10.1016/j.scitotenv.2017.03.255Liu, Y., Song, M., Liu, X., Zhang, Y., Hui, L., Kong, L., Zhang, Y., Zhang, C., Qu, Y., An, J., Ma, D., Tan, Q., & Feng, M. (2020). Characterization and sources of volatile organic compounds (VOCs) and their related changes during ozone pollution days in 2016 in Beijing, China. Environmental Pollution, 257, 113599. https://doi.org/10.1016/j.envpol.2019.113599Liu, Y., Wang, T., Stavrakou, T., Elguindi, N., Doumbia, T., Granier, C., Bouarar, I., Gaubert, B., & Brasseur, G. P. (2021). Diverse response of surface ozone to COVID-19 lockdown in China. Science of The Total Environment, 789, 147739. https://doi.org/10.1016/j.scitotenv.2021.147739Liu, Z., Wang, H., Shen, X., Peng, Y., Shi, Y., Che, H., & Wang, G. (2019). Contribution of Meteorological Conditions to the Variation in Winter PM2.5 Concentrations from 2013 to 2019 in Middle-Eastern China. In Atmosphere (Vol. 10, Issue 10). https://doi.org/10.3390/atmos10100563Luo, M., Hou, X., Gu, Y., Lau, N.-C., & Yim, S. H.-L. (2018). Trans-boundary air pollution in a city under various atmospheric conditions. In Science of the Total Environment (Vol. 618, pp. 132–141). https://doi.org/10.1016/j.scitotenv.2017.11.001Lyu, W., Li, Y., Guan, D., Zhao, H., Zhang, Q., & Liu, Z. (2016). Driving forces of Chinese primary air pollution emissions: An index decomposition analysis. Journal of Cleaner Production, 133, 136–144. https://doi.org/10.1016/j.jclepro.2016.04.093Matsumoto, K., Tominaga, S., & Igawa, M. (2011). Measurements of atmospheric aerosols with diameters greater than 10 μm and their contribution to fixed nitrogen deposition in coastal urban environment. Atmospheric Environment, 45(35), 6433–6438. https://doi.org/10.1016/j.atmosenv.2011.07.061Maynard, R. (2004). Key airborne pollutants—The impact on health. Science of The Total Environment, 334–335, 9–13. https://doi.org/10.1016/j.scitotenv.2004.04.025Melkonyan, A., & Wagner, P. (2013). Ozone and its projection in regard to climate change. Atmospheric Environment, 67, 287–295. https://doi.org/10.1016/j.atmosenv.2012.10.023Meng, C., Cheng, T., Gu, X., Shi, S., Wang, W., Wu, Y., & Bao, F. (2019). Contribution of meteorological factors to particulate pollution during winters in Beijing. Science of The Total Environment, 656, 977–985. https://doi.org/10.1016/j.scitotenv.2018.11.365Ministry of Environmental Protection of China. (2019). 2018 Report on the State of the Environment in China (in Chinese).Montzka, S. A., Butler, J. H., Hall, B. D., Mondeel, D. J., & Elkins, J. W. (2003). A decline in tropospheric organic bromine. Geophysical Research Letters, 30(15). https://doi.org/10.1029/2003GL017745Nichol, J. E., Bilal, M., Ali, M. A., & Qiu, Z. (2020). Air Pollution Scenario over China during COVID-19. Remote Sensing, 12(13), 2100. https://doi.org/10.3390/rs12132100Orellano, P., Reynoso, J., Quaranta, N., Bardach, A., & Ciapponi, A. (2020). Short-term exposure to particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), and ozone (O3) and all-cause and cause-specific mortality: Systematic review and meta-analysis. Environment International, 142, 105876. https://doi.org/10.1016/j.envint.2020.105876Ou, J., Yuan, Z., Zheng, J., Huang, Z., Shao, M., Li, Z., Huang, X., Guo, H., & Louie, P. K. K. (2016). Ambient Ozone Control in a Photochemically Active Region: Short-Term Despiking or Long-Term Attainment? Environmental Science & Technology, 50(11), 5720–5728. https://doi.org/10.1021/acs.est.6b00345Pearce, J. L., Beringer, J., Nicholls, N., Hyndman, R. J., & Tapper, N. J. (2011). Quantifying the influence of local meteorology on air quality using generalized additive models. Atmospheric Environment, 45(6), 1328–1336. https://doi.org/10.1016/j.atmosenv.2010.11.051Pei, Z., Han, G., Ma, X., Su, H., & Gong, W. (2020). Response of major air pollutants to COVID-19 lockdowns in China. Science of The Total Environment, 743, 140879. https://doi.org/10.1016/j.scitotenv.2020.140879Physick, W. L., & Goudey, R. (2001). Estimating an annual-average RSP concentration for Hong Kong using days characteristic of the dominant weather patterns. In Atmospheric Environment (Vol. 35, Issue 15, pp. 2697–2705). https://doi.org/10.1016/s1352-2310(00)00413-1Plocoste, T., Calif, R., & Jacoby-Koaly, S. (2019). Multi-scale time dependent correlation between synchronous measurements of ground-level ozone and meteorological parameters in the Caribbean Basin. Atmospheric Environment, 211, 234–246. https://doi.org/10.1016/j.atmosenv.2019.05.001Pye, H. O. T., Liao, H., Wu, S., Mickley, L. J., Jacob, D. J., Henze, D. K., & Seinfeld, J. H. (2009). Effect of changes in climate and emissions on future sulfate-nitrate-ammonium aerosol levels in the United States. In Journal of Geophysical Research-Atmospheres (Vol. 114). https://doi.org/10.1029/2008jd010701Rae, J. G. L., Johnson, C. E., Bellouin, N., Boucher, O., Haywood, J. M., & Jones, A. (2007). Sensitivity of global sulphate aerosol production to changes in oxidant concentrations and climate. In Journal of Geophysical Research-Atmospheres (Vol. 112, Issue D10). https://doi.org/10.1029/2006jd007826Ratto, G., Videla, F., Almandos, J. R., Maronna, R., & Schinca, D. (2006). Study of Meteorological Aspects and Urban Concentration of SO2 in Atmospheric Environment of La Plata, Argentina. Environmental Monitoring and Assessment, 121(1), 327–342. https://doi.org/10.1007/s10661-005-9127-zRubio, M. A., Lissi, E., & Villena, G. (2002). Nitrite in rain and dew in Santiago city, Chile. Its possible impact on the early morning start of the photochemical smog. Atmospheric Environment, 36(2), 293–297. https://doi.org/10.1016/S1352-2310(01)00356-9Seinfeld, J. H., & Pandis, S. N. (2016). Atmospheric chemistry and physics: From air pollution to climate change. John Wiley & Sons.Shao, M., Lu, S., Liu, Y., Xie, X., Chang, C., Huang, S., & Chen, Z. (2009). Volatile organic compounds measured in summer in Beijing and their role in ground-level ozone formation. Journal of Geophysical Research: Atmospheres, 114(D2). https://doi.org/10.1029/2008JD010863Shao, P., Tian, H., Sun, Y., Liu, H., Wu, B., Liu, S., Liu, X., Wu, Y., Liang, W., Wang, Y., Gao, J., Xue, Y., Bai, X., Liu, W., Lin, S., & Hu, G. (2018). Characterizing remarkable changes of severe haze events and chemical compositions in multi-size airborne particles (PM1, PM2.5 and PM10) from January 2013 to 2016–2017 winter in Beijing, China. Atmospheric Environment, 189, 133–144. https://doi.org/10.1016/j.atmosenv.2018.06.038Shek, K. Y., Zeren, Y., Guo, H., Li, M., Liu, M., Huang, B., & Lyu, X. (2022). Insights on In-Situ Photochemistry Associated with Ozone Reduction in Guangzhou during the COVID-19 Lockdown. Atmosphere, 13(2), 212. https://doi.org/10.3390/atmos13020212Shi, X., & Brasseur, G. P. (2020). The Response in Air Quality to the Reduction of Chinese Economic Activities During the COVID-19 Outbreak. Geophysical Research Letters, 47(11), e2020GL088070. https://doi.org/10.1029/2020GL088070Shi, Y., Xia, Y., Lu, B., Liu, N., Zhang, L., Li, S., & Li, W. (2014). Emission inventory and trends of NOxfor China, 2000–2020. Journal of Zhejiang University SCIENCE A, 15(6), 454–464. https://doi.org/10.1631/jzus.A1300379Shi, Z., Song, C., Liu, B., Lu, G., Xu, J., Van Vu, T., Elliott, R. J. R., Li, W., Bloss, W. J., & Harrison, R. M. (2021). Abrupt but smaller than expected changes in surface air quality attributable to COVID-19 lockdowns. Science Advances, 7(3), eabd6696. https://doi.org/10.1126/sciadv.abd6696Song, C., He, J., Wu, L., Jin, T., Chen, X., Li, R., Ren, P., Zhang, L., & Mao, H. (2017). Health burden attributable to ambient PM2.5 in China. In Environmental Pollution (Vol. 223, pp. 575–586). https://doi.org/10.1016/j.envpol.2017.01.060Song, C., Wu, L., Xie, Y., He, J., Chen, X., Wang, T., Lin, Y., Jin, T., Wang, A., Liu, Y., Dai, Q., Liu, B., Wang, Y., & Mao, H. (2017). Air pollution in China: Status and spatiotemporal variations. In Environmental Pollution (Vol. 227, pp. 334–347). https://doi.org/10.1016/j.envpol.2017.04.075Song, Y., Lin, C., Li, Y., Lau, A. K. H., Fung, J. C. H., Lu, X., Guo, C., Ma, J., & Lao, X. Q. (2021). An improved decomposition method to differentiate meteorological and anthropogenic effects on air pollution: A national study in China during the COVID-19 lockdown period. Atmospheric Environment, 250, 118270. https://doi.org/10.1016/j.atmosenv.2021.118270Stieb, D. M., Burnett, R. T., Smith-Doiron, M., Brion, O., Shin, H. H., & Economou, V. (2008). A new multipollutant, no-threshold air quality health index based on short-term associations observed in daily time-series analyses. Journal of the Air & Waste Management Association (1995), 58(3), 435–450. https://doi.org/10.3155/1047-3289.58.3.435Stockwell, W. R. (1990). The second generation regional acid deposition model chemical mechanism for regional air quality modeling—Stockwell—1990—- Wiley Online Library. https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JD095iD10p16343Su, T., Li, Z., Zheng, Y., Luan, Q., & Guo, J. (2020). Abnormally Shallow Boundary Layer Associated With Severe Air Pollution During the COVID-19 Lockdown in China. Geophysical Research Letters, 47(20), e2020GL090041. https://doi.org/10.1029/2020GL090041Sun, J., Gong, J., Zhou, J., Liu, J., & Liang, J. (2019). Analysis of PM2.5 pollution episodes in Beijing from 2014 to 2017: Classification, interannual variations and associations with meteorological features. Atmospheric Environment, 213, 384–394. https://doi.org/10.1016/j.atmosenv.2019.06.015Tai, A. P. K., Mickley, L. J., & Jacob, D. J. (2010). Correlations between fine particulate matter (PM2.5) and meteorological variables in the United States: Implications for the sensitivity of PM2.5 to climate change. In Atmospheric Environment (Vol. 44, Issue 32, pp. 3976–3984). https://doi.org/10.1016/j.atmosenv.2010.06.060Tang, G., Liu, Y., Zhang, J., Liu, B., Li, Q., Sun, J., Wang, Y., Xuan, Y., Li, Y., Pan, J., Li, X., & Wang, Y. (2021). Bypassing the NOx titration trap in ozone pollution control in Beijing. Atmospheric Research, 249, 105333. https://doi.org/10.1016/j.atmosres.2020.105333Tie, X., Huang, R.-J., Cao, J., Zhang, Q., Cheng, Y., Su, H., Chang, D., Pöschl, U., Hoffmann, T., Dusek, U., Li, G., Worsnop, D. R., & O’Dowd, C. D. (2017). Severe Pollution in China Amplified by Atmospheric Moisture. Scientific Reports, 7(1), 15760. https://doi.org/10.1038/s41598-017-15909-1Tong, C. H. M., Yim, S. H. L., Rothenberg, D., Wang, C., Lin, C.-Y., Chen, Y. D., & Lau, N. C. (2018). Assessing the impacts of seasonal and vertical atmospheric conditions on air quality over the Pearl River Delta region. In Atmospheric Environment (Vol. 180, pp. 69–78). https://doi.org/10.1016/j.atmosenv.2018.02.039Vu, T. V., Shi, Z., Cheng, J., Zhang, Q., He, K., Wang, S., & Harrison, R. M. (2019). Assessing the impact of clean air action on air quality trends in Beijing using a machine learning technique. Atmospheric Chemistry and Physics, 19(17), 11303–11314. https://doi.org/10.5194/acp-19-11303-2019Wang, G., Cheng, S., Wei, W., Yang, X., Wang, X., Jia, J., Lang, J., & Lv, Z. (2017). Characteristics and emission-reduction measures evaluation of PM2.5 during the two major events: APEC and Parade. Science of The Total Environment, 595, 81–92. https://doi.org/10.1016/j.scitotenv.2017.03.231Wang, H., Chen, H., & Liu, J. (2015). Arctic Sea Ice Decline Intensified Haze Pollution in Eastern China. In Atmospheric and Oceanic Science Letters (Vol. 8, Issue 1, pp. 1–9).Wang, N., Lyu, X., Deng, X., Huang, X., Jiang, F., & Ding, A. (2019). Aggravating O3 pollution due to NOx emission control in eastern China. Science of The Total Environment, 677, 732–744. https://doi.org/10.1016/j.scitotenv.2019.04.388Wang, N., Xu, J., Pei, C., Tang, R., Zhou, D., Chen, Y., Li, M., Deng, X., Deng, T., Huang, X., & Ding, A. (2021). Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China. Environmental Science & Technology, 55(9), 5721–5730. https://doi.org/10.1021/acs.est.0c08383Wang, P., Chen, K., Zhu, S., Wang, P., & Zhang, H. (2020). Severe air pollution events not avoided by reduced anthropogenic activities during COVID-19 outbreak. Resources, Conservation and Recycling, 158, 104814. https://doi.org/10.1016/j.resconrec.2020.104814Wang, Q., Sun, Y., Xu, W., Du, W., Zhou, L., Tang, G., Chen, C., Cheng, X., Zhao, X., Ji, D., Han, T., Wang, Z., Li, J., & Wang, Z. (2018). Vertically resolved characteristics of air pollution during two severe winter haze episodes in urban Beijing, China. Atmospheric Chemistry and Physics, 18(4), 2495–2509. https://doi.org/10.5194/acp-18-2495-2018Wang, S., Zhang, Y., Ma, J., Zhu, S., Shen, J., Wang, P., & Zhang, H. (2021). Responses of decline in air pollution and recovery associated with COVID-19 lockdown in the Pearl River Delta. Science of The Total Environment, 756, 143868. https://doi.org/10.1016/j.scitotenv.2020.143868Wang, X., Zhong, S., Bian, X., & Yu, L. (2019). Impact of 2015-2016 El Nino and 2017-2018 La Nina on PM2.5 concentrations across China. In Atmospheric Environment (Vol. 208, pp. 61–73). https://doi.org/10.1016/j.atmosenv.2019.03.035Wang, Y., Wen, Y., Wang, Y., Zhang, S., Zhang, K. M., Zheng, H., Xing, J., Wu, Y., & Hao, J. (2020). Four-Month Changes in Air Quality during and after the COVID-19 Lockdown in Six Megacities in China. Environmental Science & Technology Letters, 7(11), 802–808. https://doi.org/10.1021/acs.estlett.0c00605West, J. J., Cohen, A., Dentener, F., Brunekreef, B., Zhu, T., Armstrong, B., Bell, M. L., Brauer, M., Carmichael, G., Costa, D. L., Dockery, D. W., Kleeman, M., Krzyzanowski, M., Kuenzli, N., Liousse, C., Lung, S.-C. C., Martin, R. V., Poeschl, U., Pope, I., C. Arden, … Wiedinmyer, C. (2016). What We Breathe Impacts Our Health: Improving Understanding of the Link between Air Pollution and Health. In Environmental Science & Technology (Vol. 50, Issue 10, pp. 4895–4904). https://doi.org/10.1021/acs.est.5b03827WHO. (2000a). Air quality guidelines for Europe. World Health Organization. Regional Office for Europe.WHO. (2000b). Evaluation and use of epidemiological evidence for environmental health risk assessment: WHO guideline document. Environmental Health Perspectives, 997–1002.WHO. (2006). Air Quality Guidelines for Particulate Matter, Ozone, Nitrogen Dioxide and Sulfur Dioxide: Global Update 2005. WHO Press.WHO. (2013). Health effects of particulate matter: Policy implications for countries in eastern Europe, Caucasus and central Asia. World Health Organization. Regional Office for Europe. https://apps.who.int/iris/handle/10665/344854WHO. (2016). WHO releases country estimates on air pollution exposure and health impact. World Health Organization.WHO. (2021). WHO global air quality guidelines: Particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. World Health Organization.Wong, T. W., Tam, W. W. S., Yu, I. T. S., Lau, A. K. H., Pang, S. W., & Wong, A. H. S. (2013). Developing a risk-based air quality health index. Atmospheric Environment, 76, 52–58. https://doi.org/10.1016/j.atmosenv.2012.06.071Woodward, A., Smith, K. R., Campbell-Lendrum, D., Chadee, D. D., Honda, Y., Liu, Q., Olwoch, J., Revich, B., Sauerborn, R., Chafe, Z., Confalonieri, U., & Haines, A. (2014). Climate change and health: On the latest IPCC report. In Lancet (Vol. 383, Issue 9924, pp. 1185–1189). https://doi.org/10.1016/s0140-6736(14)60576-6Wu, D. W., Fung, J. C. H., Yao, T., & Lau, A. K. H. (2013). A study of control policy in the Pearl River Delta region by using the particulate matter source apportionment method. In Atmospheric Environment (Vol. 76, pp. 147–161). https://doi.org/10.1016/j.atmosenv.2012.11.069Wu, Z., Zhang, Y., Zhang, L., Huang, M., Zhong, L., Chen, D., & Wang, X. (2019). Trends of outdoor air pollution and the impact on premature mortality in the Pearl River Delta region of southern China during 2006–2015. Science of The Total Environment, 690, 248–260. https://doi.org/10.1016/j.scitotenv.2019.06.401Xiang, S., Liu, J., Tao, W., Yi, K., Xu, J., Hu, X., Liu, H., Wang, Y., Zhang, Y., Yang, H., Hu, J., Wan, Y., Wang, X., Ma, J., Wang, X., & Tao, S. (2020). Control of both PM2.5 and O3 in Beijing-Tianjin-Hebei and the surrounding areas. Atmospheric Environment, 224, 117259. https://doi.org/10.1016/j.atmosenv.2020.117259Xing, J., Li, S., Jiang, Y., Wang, S., Ding, D., Dong, Z., Zhu, Y., & Hao, J. (2020). Quantifying the emission changes and associated air quality impacts during the COVID-19 pandemic in North China Plain: A response modeling study. Atmospheric Chemistry and Physics Discussions, 1–28. https://doi.org/10.5194/acp-2020-522Xu, J., Chang, L., Qu, Y., Yan, F., Wang, F., & Fu, Q. (2016). The meteorological modulation on PM2.5 interannual oscillation during 2013 to 2015 in Shanghai, China. In Science of the Total Environment (Vol. 572, pp. 1138–1149). https://doi.org/10.1016/j.scitotenv.2016.08.024Xu, Y., Xue, W., Lei, Y., Huang, Q., Zhao, Y., Cheng, S., Ren, Z., & Wang, J. (2020). Spatiotemporal variation in the impact of meteorological conditions on PM2.5 pollution in China from 2000 to 2017. Atmospheric Environment, 223, 117215. https://doi.org/10.1016/j.atmosenv.2019.117215Yang, D., Wang, X., Xu, J., Xu, C., Lu, D., Ye, C., Wang, Z., & Bai, L. (2018). Quantifying the influence of natural and socioeconomic factors and their interactive impact on PM2.5 pollution in China. Environmental Pollution, 241, 475–483. https://doi.org/10.1016/j.envpol.2018.05.043Yim, S. H. L., Hou, X., Guo, J., & Yang, Y. (2019). Contribution of local emissions and transboundary air pollution to air quality in Hong Kong during El Nino-Southern Oscillation and heatwaves. In Atmospheric Research (Vol. 218, pp. 50–58). https://doi.org/10.1016/j.atmosres.2018.10.021Yin, C., Li, T., Zou, Y., Li, F., Mai, B., Deng, T., & Wang, N. (2017). 2016 Guangdong haze weather bulletin (in Chinese).Yin, H., Liu, C., Hu, Q., Liu, T., Wang, S., Gao, M., Xu, S., Zhang, C., & Su, W. (2021). Opposite impact of emission reduction during the COVID-19 lockdown period on the surface concentrations of PM2.5 and O3 in Wuhan, China. Environmental Pollution, 289, 117899. https://doi.org/10.1016/j.envpol.2021.117899Yin, Z., Cao, B., & Wang, H. (2019). Dominant patterns of summer ozone pollution in eastern China and associated atmospheric circulations. In Atmospheric Chemistry and Physics (Vol. 19, Issue 22, pp. 13933–13943). https://doi.org/10.5194/acp-19-13933-2019Yu, D., Tan, Z., Lu, K., Ma, X., Li, X., Chen, S., Zhu, B., Lin, L., Li, Y., Qiu, P., Yang, X., Liu, Y., Wang, H., He, L., Huang, X., & Zhang, Y. (2020). An explicit study of local ozone budget and NOx-VOCs sensitivity in Shenzhen China. Atmospheric Environment, 224, 117304. https://doi.org/10.1016/j.atmosenv.2020.117304Yu, S., Su, F., Yin, S., Wang, S., Xu, R., He, B., Fan, X., Yuan, M., & Zhang, R. (2021). Characterization of ambient volatile organic compounds, source apportionment, and the ozone–NOx–VOC sensitivities in a heavily polluted megacity of central China: Effect of sporting events and emission reductions. Atmospheric Chemistry and Physics, 21(19), 15239–15257. https://doi.org/10.5194/acp-21-15239-2021Yue, Y., Wang, X., Zhang, M., Cao, W., Zhou, Y., Chen, S., & Zhu, Y. (2016). Air quality condition in Wuhan and its relationship to meteorological factors (in Chinese). Torrential Rain and Disasters, 35(3), 271–278.Zavala, M., Brune, W. H., Velasco, E., Retama, A., Cruz-Alavez, L. A., & Molina, L. T. (2020). Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area. Atmospheric Environment, 238, 117747. https://doi.org/10.1016/j.atmosenv.2020.117747Zeng, Y., Cao, Y., Qiao, X., Seyler, B. C., & Tang, Y. (2019). Air pollution reduction in China: Recent success but great challenge for the future. In Science of the Total Environment (Vol. 663, pp. 329–337). https://doi.org/10.1016/j.scitotenv.2019.01.262Zhai, S., Jacob, D. J., Wang, X., Shen, L., Li, K., Zhang, Y., Gui, K., Zhao, T., & Liao, H. (2019). Fine particulate matter (PM2.5) trends in China, 2013–2018: Separating contributions from anthropogenic emissions and meteorology. Atmospheric Chemistry and Physics, 19(16), 11031–11041. https://doi.org/10.5194/acp-19-11031-2019Zhang, J. P., Zhu, T., Zhang, Q. H., Li, C. C., Shu, H. L., Ying, Y., Dai, Z. P., Wang, X., Liu, X. Y., Liang, A. M., Shen, H. X., & Yi, B. Q. (2012). The impact of circulation patterns on regional transport pathways and air quality over Beijing and its surroundings. In Atmospheric Chemistry and Physics (Vol. 12, Issue 11, pp. 5031–5053). https://doi.org/10.5194/acp-12-5031-2012Zhang, K., Liu, Z., Zhang, X., Li, Q., Jensen, A., Tan, W., Huang, L., Wang, Y., de Gouw, J., & Li, L. (2022). Insights into the significant increase in ozone during COVID-19 in a typical urban city of China. Atmospheric Chemistry and Physics, 22(7), 4853–4866. https://doi.org/10.5194/acp-22-4853-2022Zhang, K., Xu, J., Huang, Q., Zhou, L., Fu, Q., Duan, Y., & Xiu, G. (2020). Precursors and potential sources of ground-level ozone in suburban Shanghai. Frontiers of Environmental Science & Engineering, 14(6), 92. https://doi.org/10.1007/s11783-020-1271-8Zhang, M., Shan, C., Wang, W., Pang, J., & Guo, S. (2020). Do driving restrictions improve air quality: Take Beijing-Tianjin for example? In Science of the Total Environment (Vol. 712). https://doi.org/10.1016/j.scitotenv.2019.136408Zhang, Q., Ma, Q., Zhao, B., Liu, X., Wang, Y., Jia, B., & Zhang, X. (2018). Winter haze over North China Plain from 2009 to 2016: Influence of emission and meteorology. Environmental Pollution, 242, 1308–1318. https://doi.org/10.1016/j.envpol.2018.08.019Zhang, Q., Pan, Y., He, Y., Walters, W. W., Ni, Q., Liu, X., Xu, G., Shao, J., & Jiang, C. (2021). Substantial nitrogen oxides emission reduction from China due to COVID-19 and its impact on surface ozone and aerosol pollution. Science of The Total Environment, 753, 142238. https://doi.org/10.1016/j.scitotenv.2020.142238Zhang, Q., Quan, J., Tie, X., Li, X., Liu, Q., Gao, Y., & Zhao, D. (2015). Effects of meteorology and secondary particle formation on visibility during heavy haze events in Beijing, China. In Science of the Total Environment (Vol. 502, pp. 578–584). https://doi.org/10.1016/j.scitotenv.2014.09.079Zhang, Q., Zheng, Y., Tong, D., Shao, M., Wang, S., Zhang, Y., Xu, X., Wang, J., He, H., Liu, W., Ding, Y., Lei, Y., Li, J., Wang, Z., Zhang, X., Wang, Y., Cheng, J., Liu, Y., Shi, Q., … Hao, J. (2019). Drivers of improved PM2.5 air quality in China from 2013 to 2017. In Proceedings of the National Academy of Sciences of the United States of America (Vol. 116, Issue 49, pp. 24463–24469). https://doi.org/10.1073/pnas.1907956116Zhang, R., Li, Q., & Zhang, R. (2014). Meteorological conditions for the persistent severe fog and haze event over eastern China in January 2013. Science China Earth Sciences, 57(1), 26–35. https://doi.org/10.1007/s11430-013-4774-3Zhang, W., Wang, H., Zhang, X., Peng, Y., Zhong, J., Wang, Y., & Zhao, Y. (2020). Evaluating the contributions of changed meteorological conditions and emission to substantial reductions of PM2.5 concentration from winter 2016 to 2017 in Central and Eastern China. Science of The Total Environment, 716, 136892. https://doi.org/10.1016/j.scitotenv.2020.136892Zhang, Y., Ding, A., Mao, H., Nie, W., Zhou, D., Liu, L., Huang, X., & Fu, C. (2016). Impact of synoptic weather patterns and inter-decadal climate variability on air quality in the North China Plain during 1980-2013. In Atmospheric Environment (Vol. 124, pp. 119–128). https://doi.org/10.1016/j.atmosenv.2015.05.063Zhao, H., Niu, Z., & Feng, X. (2021). Factors influencing improvements in air quality in Guanzhong cities of China, and variations therein for 2014–2020. Urban Climate, 38, 100877. https://doi.org/10.1016/j.uclim.2021.100877Zhao, N., Wang, G., Li, G., Lang, J., & Zhang, H. (2020). Air pollution episodes during the COVID-19 outbreak in the Beijing–Tianjin–Hebei region of China: An insight into the transport pathways and source distribution. Environmental Pollution, 267, 115617. https://doi.org/10.1016/j.envpol.2020.115617Zhao, S. Y., Zhang, H., & Xie, B. (2018). The effects of El Nino-Southern Oscillation on the winter haze pollution of China. In Atmospheric Chemistry and Physics (Vol. 18, Issue 3, pp. 1863–1877). https://doi.org/10.5194/acp-18-1863-2018Zhao, S., Yin, D., Yu, Y., Kang, S., Qin, D., & Dong, L. (2020). PM2.5 and O3 pollution during 2015–2019 over 367 Chinese cities: Spatiotemporal variations, meteorological and topographical impacts. Environmental Pollution, 264, 114694. https://doi.org/10.1016/j.envpol.2020.114694Zhao, Y., Ma, S., Fan, J., & Cai, Y. (2021). Examining the Effects of Land Use on Carbon Emissions: Evidence from Pearl River Delta. International Journal of Environmental Research and Public Health, 18(7), 3623. https://doi.org/10.3390/ijerph18073623Zhao, Y., Zhang, K., Xu, X., Shen, H., Zhu, X., Zhang, Y., Hu, Y., & Shen, G. (2020). Substantial Changes in Nitrogen Dioxide and Ozone after Excluding Meteorological Impacts during the COVID-19 Outbreak in Mainland China. Environmental Science & Technology Letters, 7(6), 402–408. https://doi.org/10.1021/acs.estlett.0c00304Zheng, B., Tong, D., Li, M., Liu, F., Hong, C., Geng, G., Li, H., Li, X., Peng, L., Qi, J., Yan, L., Zhang, Y., Zhao, H., Zheng, Y., He, K., & Zhang, Q. (2018). Trends in China’s anthropogenic emissions since 2010 as the consequence of clean air actions. In Atmospheric Chemistry and Physics (Vol. 18, Issue 19, pp. 14095–14111). https://doi.org/10.5194/acp-18-14095-2018Zheng, B., Zhang, Q., Geng, G., Chen, C., Shi, Q., Cui, M., Lei, Y., & He, K. (2021). Changes in China’s anthropogenic emissions and air quality during the COVID-19 pandemic in 2020. Earth System Science Data, 13(6), 2895–2907. https://doi.org/10.5194/essd-13-2895-2021Zheng, G. J., Duan, F. K., Su, H., Ma, Y. L., Cheng, Y., Zheng, B., Zhang, Q., Huang, T., Kimoto, T., Chang, D., Pöschl, U., Cheng, Y. F., & He, K. B. (2015). Exploring the severe winter haze in Beijing: The impact of synoptic weather, regional transport and heterogeneous reactions. Atmospheric Chemistry and Physics, 15(6), 2969–2983. https://doi.org/10.5194/acp-15-2969-2015Zheng, X., Orellano, P., Lin, H., Jiang, M., & Guan, W. (2021). Short-term exposure to ozone, nitrogen dioxide, and sulphur dioxide and emergency department visits and hospital admissions due to asthma: A systematic review and meta-analysis. Environment International, 150, 106435. https://doi.org/10.1016/j.envint.2021.106435Zhong, J. T., Zhang, X. Y., Wang, Y. Q., Sun, J. Y., Zhang, Y. M., Wang, J. Z., Tan, K. Y., Shen, X. J., Che, H. C., Zhang, L., Zhang, Z. X., Qi, X. F., Zhao, H. R., Ren, S. X., & Li, Y. (2017). Relative Contributions of Boundary-Layer Meteorological Factors to the Explosive Growth of PM2.5 during the Red-Alert Heavy Pollution Episodes in Beijing in December 2016. In Journal of Meteorological Research (Vol. 31, Issue 5, pp. 809–819). https://doi.org/10.1007/s13351-017-7088-0Zhong, Q., Ma, J., Shen, G., Shen, H., Zhu, X., Yun, X., Meng, W., Cheng, H., Liu, J., Li, B., Wang, X., Zeng, E. Y., Guan, D., & Tao, S. (2018). Distinguishing Emission-Associated Ambient Air PM2.5 Concentrations and Meteorological Factor-Induced Fluctuations. Environmental Science & Technology, 52(18), 10416–10425. https://doi.org/10.1021/acs.est.8b02685Zhu, W., Xu, X., Zheng, J., Yan, P., Wang, Y., & Cai, W. (2018). The characteristics of abnormal wintertime pollution events in the Jing-Jin-Ji region and its relationships with meteorological factors. In Science of the Total Environment (Vol. 626, pp. 887–898). https://doi.org/10.1016/j.scitotenv.2018.01.083Ziemke, J. R., Oman, L. D., Strode, S. A., Douglass, A. R., Olsen, M. A., McPeters, R. D., Bhartia, P. K., Froidevaux, L., Labow, G. J., Witte, J. C., Thompson, A. M., Haffner, D. P., Kramarova, N. A., Frith, S. M., Huang, L.-K., Jaross, G. R., Seftor, C. J., Deland, M. T., & Taylor, S. L. (2019). Trends in global tropospheric ozone inferred from a composite record of TOMS/OMI/MLS/OMPS satellite measurements and the MERRA-2 GMI simulation. Atmospheric Chemistry and Physics, 19(5), 3257–3269. https://doi.org/10.5194/acp-19-3257-2019Zou, Y., Wang, Y., Zhang, Y., & Koo, J.-H. (2017). Arctic sea ice, Eurasia snow, and extreme winter haze in China. Science Advances, 3(3), e1602751. https://doi.org/10.1126/sciadv.1602751