Impact of the COVID-19 lockdown on air pollution in an industrial city in Northeastern China
Abstract
Many studies in China investigated how the lockdown following the coronavirus disease 2019 substantially affected air quality; however, few were conducted in Northeastern China. Here, the changes in six criteria air pollutants, including particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and ozone (O3), were investigated in Shenyang from January to May 2015–2020. Compared with the pre-lockdown, the mass concentrations of PM2.5, PM10, SO2, NO2, and CO during the lockdown decreased by 40.3% to 48.6%, indicating a positive impact of lockdown policies on reducing pollutant emissions. The responses of PM2.5, PM10, and CO to the lockdown measures in downtown areas were more sensitive than in the suburbs. However, the O3 concentration showed the opposite trend, attributed to the drop in NOx and particulate matters. Compared to the same period in 2015–2019, the proportion of days with good air quality increased from 63.2% to 77.2% during the lockdown and Shenyang experienced no severe pollution. Our results suggest that reducing human activities can improve air quality; however, coordinated control policies of O3, PM2.5, and NO2 are imperative.
Keyword : novel coronavirus, air quality index, spatiotemporal distribution, lockdown, particulate matter, nitrogen dioxide, carbon monoxide, sulfur dioxide, ozone
How to Cite
Wang, X., Wang, Y., Zhao, Y., Tian, M., Wu, X., Zhang, Y., Gao, F., Sun, J., Wei, X., Yang, X., & Qu, X. (2023). Impact of the COVID-19 lockdown on air pollution in an industrial city in Northeastern China. Journal of Environmental Engineering and Landscape Management, 31(3), 219–231. https://doi.org/10.3846/jeelm.2023.19472
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
Adam, M. G., Tran, P. T. M., & Balasubramanian, R. (2021). Air quality changes in cities during the COVID-19 lockdown: A critical review. Atmospheric Research, 264, 105823. https://doi.org/10.1016/j.atmosres.2021.105823
Allison, L. S. (2020). Role of the terrestrial biosphere in atmospheric chemistry and climate. Accounts of Chemical Research, 53(7), 1260–1268. https://doi.org/10.1021/acs.accounts.0c00116
Bagherinia, M., Bodaghpour, S., Karimi, N., Ghasempour, F., Bilal, M., & Mhawish, A. (2023). Spatio-temporal air quality assessment in Tehran, Iran, during the COVID-19 lockdown periods. Geocarto International, 38(1), 2169374. https://doi.org/10.1080/10106049.2023.2169374
Bao, R., & Zhang, A. (2020). Does lockdown reduce air pollution? Evidence from 44 cities in northern China. Science of the Total Environment, 731, 139052. https://doi.org/10.1016/j.scitotenv.2020.139052
Cai, W., Wang, H., Wu, C., Lu, K., Peng, Z., & He, H. (2021). Characterizing the interruption-recovery patterns of urban air pollution under the COVID-19 lockdown in China. Building and Environment, 205, 108231. https://doi.org/10.1016/j.buildenv.2021.108231
Cao, X., Liu, X., Hadiatullah, H., Xu, Y., Zhang, X., Cyrys, J., Zimmermann, R., & Adam, T. (2022). Investigation of COVID-19-related lockdowns on the air pollution changes in Augsburg in 2020, Germany. Atmospheric Pollution Research, 13(9), 101536. https://doi.org/10.1016/j.apr.2022.101536
Chen, Y., Bai, Y., Liu, H., Alatalo, J. M., & Jiang, B. (2020). Temporal variations in ambient air quality indicators in Shanghai municipality, China. Scientific Reports, 10(1), 11350. https://doi.org/10.1038/s41598-020-68201-0
Chen, Z., Hao, X., Zhang, X., & Chen, F. (2021). Have traffic restrictions improved air quality? A shock from COVID-19. Journal of Cleaner Production, 279, 123622. https://doi.org/10.1016/j.jclepro.2020.123622
Chu, 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.2020.06.031
Coates, J., Mar, K. A., Ojha, N., & Butler, T. M. (2016). The influence of temperature on ozone production under varying NOx conditions – a modelling study. Atmospheric Chemistry and Physics, 16(18), 11601–11615. https://doi.org/10.5194/acp-16-11601-2016
Cooper, M. J., Martin, R. V., Hammer, M. S., Levelt, P. F., Veefkind, P., Lamsal, L. N., Krotkov, N. A., Brook, J. R., & McLinden, C. A. (2022). Global fine-scale changes in ambient NO2 during COVID-19 lockdowns. Nature, 601(7893), 380–387. https://doi.org/10.1038/s41586-021-04229-0
Dong, X., Zheng, X., Wang, C., Zeng, J., & Zhang, L. (2022). Air pollution rebound and different recovery modes during the period of easing COVID-19 restrictions. Science of the Total Environment, 843, 156942. https://doi.org/10.1016/j.scitotenv.2022.156942
Filonchyk, M., & Peterson, M. (2020). Air quality changes in Shanghai, China, and the surrounding urban agglomeration during the COVID-19 lockdown. Journal of Geovisualization and Spatial Analysis, 4(2), 22. https://doi.org/10.1007/s41651-020-00064-5
Gao, C., Zhang, F., Fang, D., Wang, Q., & Liu, M. (2023). Spatial characteristics of change trends of air pollutants in Chinese urban areas during 2016–2020: The impact of air pollution controls and the COVID-19 pandemic. Atmospheric Research, 283, 106539. https://doi.org/10.1016/j.atmosres.2022.106539
Grange, S. K., Lee, J. D., Drysdale, W. S., Lewis, A. C., Hueglin, C., Emmenegger, L., & Carslaw, D. C. (2021). COVID-19 lockdowns highlight a risk of increasing ozone pollution in European urban areas. Atmospheric Chemistry and Physics, 21(5), 4169–4185. https://doi.org/10.5194/acp-21-4169-2021
Guo, Q., He, Z., & Wang, Z. (2023). Change in air quality during 2014–2021 in Jinan City in China and its influencing factors. Toxics, 11(3), 210. https://doi.org/10.3390/toxics11030210
Hammad, H. M., Nauman, H. M. F., Abbas, F., Jawad, R., Farhad, W., Shahid, M., Bakhat, H. F., Farooque, A. A., Mubeen, M., Fahad, S., & Cerda, A. (2023). Impacts of COVID-19 pandemic on environment, society, and food security. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-023-25714-1
Han, J., Yin, J., Wu, X., Wang, D., & Li, C. (2023). Environment and COVID-19 incidence: A critical review. Journal of Environmental Sciences, 124, 933–951. https://doi.org/10.1016/j.jes.2022.02.016
Harapan, H., Itoh, N., Yufika, A., Winardi, W., Keam, S., Te, H., Megawati, D., Hayati, Z., Wagner, A. L., & Mudatsir, M. (2020). Coronavirus disease 2019 (COVID-19): A literature review. Journal of Infection and Public Health, 13(5), 667–673. https://doi.org/10.1016/j.jiph.2020.03.019
Hasnain, A., Hashmi, M. Z., Bhatti, U. A., Nadeem, B., Wei, G., Zha, Y., & Sheng, Y. (2021). Assessment of air pollution before, during and after the COVID-19 pandemic lockdown in Nanjing, China. Atmosphere, 12, 743. https://doi.org/10.3390/atmos12060743
He, G., Pan, Y., & Tanaka, T. (2020). The short-term impacts of COVID-19 lockdown on urban air pollution in China. Nature Sustainability, 3(12), 1005–1011. https://doi.org/10.1038/s41893-020-0581-y
Huang, C., Wang, T., Niu, T., Han, J., Li, M., Zhang, N., Liu, H., & Ma, C. (2021). Study on the causes of heavy pollution in Shenyang based on the contribution of natural conditions, physical processes, and anthropogenic emissions. Atmospheric Pollution Research, 12(4), 101224. https://doi.org/10.1016/j.apr.2021.101224
Huang, 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, 8(2), nwaa137. https://doi.org/10.1093/nsr/nwaa137
Huang, Y., & Li, R. (2022). The lockdown, mobility, and spatial health disparities in COVID-19 pandemic: A case study of New York City. Cities, 122, 103549. https://doi.org/10.1016/j.cities.2021.103549
Jia, H., Zang, S., Zhang, L., Yakovleva, E., Sun, H., & Sun, L. (2023). Spatiotemporal characteristics and socioeconomic factors of PM2.5 heterogeneity in mainland China during the COVID-19 epidemic. Chemosphere, 331, 138785. https://doi.org/10.1016/j.chemosphere.2023.138785
Kulkarni, P. S., Bortoli, D., & Silva, A. M. (2013). Nocturnal surface ozone enhancement and trend over urban and suburban sites in Portugal. Atmospheric Environment, 71, 251–259. https://doi.org/10.1016/j.atmosenv.2013.01.051
Kumar, A., Dhakhwa, S., & Dikshit, A. K. (2022). Comparative evaluation of fitness of interpolation techniques of ArcGIS using leave-one-out scheme for air quality mapping. Journal of Geovisualization and Spatial Analysis, 6(1), 9. https://doi.org/10.1007/s41651-022-00102-4
Le, 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, 369(6504), 702–706. https://doi.org/10.1126/science.abb7431
Li, D., & Lasenby, J. (2023). Investigating impacts of COVID-19 on urban mobility and emissions. Cities, 135, 104246. https://doi.org/10.1016/j.cities.2023.104246
Li, 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 of the United States of America, 116(2), 422–427. https://doi.org/10.1073/pnas.1812168116
Li, K., Ni, R., Jiang, T., Tian, Y., Zhang, X., Li, C., & Xie, C. (2022). The regional impact of the COVID-19 lockdown on the air quality in Ji’nan, China. Scientific Reports, 12(1), 12099. https://doi.org/10.1038/s41598-022-16105-6
Li, 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.2020.139282
Liang, Q., Liu, S., Yin, J., Han, Q., Zhang, W., & Niu, J. (2023). Spatial–temporal characteristics and influencing mechanisms of air quality index by considering COVID-19 in Yunnan, Southeastern Tibetan Plateau. Atmosphere, 14(2), 378. https://doi.org/10.3390/atmos14020378
Liu, 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 and Technology Letters, 7(11), 779–786. https://doi.org/10.1021/acs.estlett.0c00511
Llaguno-Munitxa, M., & Bou-Zeid, E. (2023). Role of vehicular emissions in urban air quality: The COVID-19 lockdown experiment. Transportation Research Part D: Transport and Environment, 115, 103580. https://doi.org/10.1016/j.trd.2022.103580
Luo, L., Bai, X., Lv, Y., Liu, S., Guo, Z., Liu, W., Hao, Y., Sun, Y., Hao, J., Zhang, K., Zhao, H., Lin S., Zhao, S., Xiao, Y., Yang, J., & Tian, H. (2022). Exploring the driving factors of haze events in Beijing during Chinese New Year holidays in 2020 and 2021 under the influence of COVID-19 pandemic. Science of the Total Environment, 859(1), 160172. https://doi.org/10.1016/j.scitotenv.2022.160172
Ma, Q., Wang, J., Xiong, M., & Zhu, L. (2023). Air Quality Index (AQI) did not improve during the COVID-19 lockdown in Shanghai, China, in 2022, based on ground and TROPOMI observations. Remote Sensing, 15(5), 1295. https://doi.org/10.3390/rs15051295
Ma, Y., Wang, M., Wang, S., Wang, Y., Feng, L., & Wu, K. (2021). Air pollutant emission characteristics and HYSPLIT model analysis during heating period in Shenyang, China. Environmental Monitoring and Assessment, 193(1), 9. https://doi.org/10.1007/s10661-020-08767-4
Mamtimin, A., Wang, Y., Zhao, T., Sayit, H., Yang, F., Huo, W., Zhou, C., & Gao, J. (2022). Impacts of winter and summer COVID-19 lockdowns on urban air quality in Urumqi, Northwest China. Frontiers in Environmental Science, 10, 910579. https://doi.org/10.3389/fenvs.2022.910579
Mo, Z., Huang, J., Chen, Z., Zhou, B., Zhu, K., Liu, H., Mu, Y., Zhang, D., & Wang, S. (2021). Cause analysis of PM2.5 pollution during the COVID-19 lockdown in Nanning, China. Scientific Reports, 11(1), 1–13. https://doi.org/10.1038/s41598-021-90617-5
Pushpawela, B., Shelton, S., Liyanage, G., Jayasekara, S., Rajapaksha, D., Jayasundara, A., & Jayasuriya, L. D. (2023). Changes of air pollutants in urban cities during the COVID-19 lockdown-Sri Lanka. Aerosol and Air Quality Research, 23(3), 220223. https://doi.org/10.4209/aaqr.220223
Ren, Y., Guan, X., Zhang, Q., Li, L., Tao, C., Ren, S., Wang, Q., & Wang, W. (2023). A machine learning-based study on the impact of COVID-19 on three kinds of pollution in Beijing-Tianjin-Hebei region. Science of the Total Environment, 884, 163190. https://doi.org/10.1016/j.scitotenv.2023.163190
Rupakheti, D., Yin, X., Rupakheti, M., Zhang, Q., Li, P., Rai, M., & Kang, S. (2021). Spatio-temporal characteristics of air pollutants over Xinjiang, northwestern China. Environmental Pollution, 268, 115907. https://doi.org/10.1016/j.envpol.2020.115907
Sbai, S. E., Mejjad, N., Norelyaqine, A., & Bentayeb, F. (2021). Air quality change during the COVID-19 pandemic lockdown over the Auvergne-Rhone-Alpes region, France. Air Quality, Atmosphere and Health, 14(5), 617–628. https://doi.org/10.1007/s11869-020-00965-w
Sekar, A., Jasna, R. S., Binoy, B. V., Mohan, P., & Kuttiparichel Varghese, G. (2023). Air quality change and public perception during the COVID-19 lockdown in India. Gondwana Research, 114, 15–29. https://doi.org/10.1016/j.gr.2022.04.023
Sharma, S., Zhang, M., Anshika, Gao, J., Zhang, H., & Kota, S. H. (2020). Effect of restricted emissions during COVID-19 on air quality in India. Science of the Total Environment, 728, 138878. https://doi.org/10.1016/j.scitotenv.2020.138878
Sicard, P., De Marco, A., Agathokleous, E., Feng, Z., Xu, X., Paoletti, E., Rodriguez, J. J. D., & Calatayud, V. (2020). Amplified ozone pollution in cities during the COVID-19 lockdown. Science of the Total Environment, 735, 139542. https://doi.org/10.1016/j.scitotenv.2020.139542
Singh, V., Singh, S., Biswal, A., Kesarkar, A.P., Mor, S., & Ravindra, K. (2020). Diurnal and temporal changes in air pollution during COVID-19 strict lockdown over different regions of India. Environmental Pollution, 266(Part 3), 115368. https://doi.org/10.1016/j.envpol.2020.115368
Song, Y., Li, Z., Liu, J., Yang, T., Zhang, M., & Pang, J. (2021). The effect of environmental regulation on air quality in China: A natural experiment during the COVID-19 pandemic. Atmospheric Pollution Research, 12(4), 21–30. https://doi.org/10.1016/j.apr.2021.02.010
Vadiati, M., Ghasemi, L., Samani, S., Islam, M. A., Ahmadi, A., Khaleghi, S., Movarej, M., Gorgij, A. D., Kisi, O., Davoodi, S., Dhama, K., Tiwari, A., & Bhattacharya, P. (2023). A sustainable trend in COVID-19 research: An environmental perspective. Frontiers in Environmental Science, 11, 1104679. https://doi.org/10.3389/fenvs.2023.1104679
Wang, H., Miao, Q., Shen, L., Yang, Q., Wu, Y., & Wei, H. (2021a). Air pollutant variations in Suzhou during the 2019 novel coronavirus (COVID-19) lockdown of 2020: High time-resolution measurements of aerosol chemical compositions and source apportionment. Environmental Pollution, 271, 116298. https://doi.org/10.1016/j.envpol.2020.116298
Wang, J., Shi, W., Xue, K., Wu, T., & Fang, C. (2023). Analysis of the impact of meteorological factors on ambient air quality during the COVID-19 lockdown in Jilin City in 2022. Atmosphere, 14(2), 400. https://doi.org/10.3390/atmos14020400
Wang, L., Li, M., Yu, S., Chen, X., Li, Z., Zhang, Y., Jiang, L., Xia, Y., Li, J., Liu, W., Li, P., Lichtfouse, E., Rosenfeld, D., & Seinfeld, J. H. (2020c). Unexpected rise of ozone in urban and rural areas, and sulfur dioxide in rural areas during the coronavirus city lockdown in Hangzhou, China: implications for air quality. Environmental Chemistry Letters, 18(368), 1713–1723. https://doi.org/10.1007/s10311-020-01028-3
Wang, L., Zhao, W., Luo, P., He, Q., Zhang, W., Dong, C., & Zhang, Y. (2024). Environmentally persistent free radicals in PM2.5 from a typical Chinese industrial city during COVID-19 lockdown: The unexpected contamination level variation. Journal of Environmental Sciences, 135, 424–432. https://doi.org/10.1016/j.jes.2022.08.024
Wang, M., Liu, F., & Zheng, M. (2021b). Air quality improvement from COVID-19 lockdown: evidence from China. Air Quality, Atmosphere and Health, 14(4), 591–604. https://doi.org/10.1007/s11869-020-00963-y
Wang, P., Chen, K., Zhu, S., Wang, P., & Zhang, H. (2020a). 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.2020.104814
Wang, X., & Zhang, R. (2020). How did air pollution change during the COVID-19 outbreak in China? Bulletin of the American Meteorological Society, 101(10), E1645–E1652. https://doi.org/10.1175/BAMS-D-20-0102.1
Wang, Y., & Ge, Q. (2023). The positive impact of the Omicron pandemic lockdown on air quality and human health in cities around Shanghai. Environment, Development and Sustainability. https://doi.org/10.1007/s10668-023-03071-w
Wang, Y., Duan, X., Liang, T., Wang, L., & Wang, L. (2022). Analysis of spatio-temporal distribution characteristics and socioeconomic drivers of urban air quality in China. Chemosphere, 291, 132799. https://doi.org/10.1016/j.chemosphere.2021.132799
Wang, Y., Gao, W., Wang, S., Song, T., Gong, Z., Ji, D., Wang, L., Liu, Z., Tang, G., Huo, Y., Tian, S., Li, J., Li, M., Yang, Y., Chu, B., Petäjä, T., Kerminen, V. M., He, H., Hao, J., ... Zhang, Y. (2020d). Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017. National Science Review, 7(8), 1331–1339. https://doi.org/10.1093/nsr/nwaa032
Wang, Y., Wen, Y., Wang, Y., Zhang, S., Zhang, K. M., Zheng, H., Xing, J., Wu, Y., & Hao, J. (2020b). Four-month changes in air quality during and after the COVID-19 lockdown in six megacities in China. Environmental Science and Technology Letters, 7(11), 802–808. https://doi.org/10.1021/acs.estlett.0c00605
Wang, Z., Li, Y., Chen, T., Li, L., Liu, B., Zhang, D., Sun, F., Wei, Q., Jiang, L., & Pan, L. (2015). Changes in atmospheric composition during the 2014 APEC conference in Beijing. Journal of Geophysical Research: Atmospheres, 120(24), 12695–12707. https://doi.org/10.1002/2015JD023652
Wong, Y. J., Yeganeh, A., Chia, M. Y., Shiu, H. Y., Ooi, M. C. G., Chang, J. H. W., Shimizu, Y., Ryosuke, H., Try, S., & Elbeltagi, A. (2023). Quantification of COVID-19 impacts on NO2 and O3: Systematic model selection and hyperparameter optimization on AI-based meteorological-normalization methods. Atmospheric Environment, 301, 119677. https://doi.org/10.1016/j.atmosenv.2023.119677
World Health Organization. (2020). Introduction to COVID-19: Methods for detection, prevention, response and control. https://openwho.org/courses/introduction-to-ncov
Xiao, K., Wang, Y., Wu, G., Fu, B., & Zhu, Y. (2018). Spatiotemporal characteristics of air pollutants (PM10, PM2.5, SO2, NO2, O3, and CO) in the inland basin city of Chengdu, southwest China. Atmosphere, 9(2), 74. https://doi.org/10.3390/atmos9020074
Xu, K., Cui, K., Young, L. H., Wang, Y. F., Hsieh, Y. K., Wan, S., & Zhang, J. (2020). Air quality index, indicatory air pollutants and impact of COVID-19 event on the air quality near central China. Aerosol and Air Quality Research, 20(6), 1204–1221. https://doi.org/10.4209/aaqr.2020.04.0139
Yang, H., Peng, Q., Zhou, J., Song, G., & Gong, X. (2020). The unidirectional causality influence of factors on PM2.5 in Shenyang city of China. Scientific Reports, 10(1), 8403. https://doi.org/10.1038/s41598-020-65391-5
Yang, J., Ji, Q., Pu, H., Dong, X., & Yang, Q. (2023). How does COVID-19 lockdown affect air quality: Evidence from Lanzhou, a large city in Northwest China. Urban Climate, 49, 101533. https://doi.org/10.1016/j.uclim.2023.101533
Yao, Y., Wang, Y., Yu, H., & Qin, H. (2021). Analysis on the influencing factors of air quality during the Spring Festival in Beijing in 2020. Environment, Development and Sustainability, 46(2), 107–114. https://doi.org/10.19758/j.cnki.issn1673-288x.202102107
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.2021.117899
Zeng, J., & Wang, C. (2022). Temporal characteristics and spatial heterogeneity of air quality changes due to the COVID-19 lockdown in China. Resources, Conservation and Recycling, 181, 106223. https://doi.org/10.1016/j.resconrec.2022.106223
Zhang, C., & Stevenson, D. (2022). Characteristic changes of ozone and its precursors in London during COVID-19 lockdown and the ozone surge reason analysis. Atmospheric Environment, 273, 118980. https://doi.org/10.1016/j.atmosenv.2022.118980
Zhang, H., Wang, Y., Hu, J., Ying, Q., & Hu, X. M. (2015). Relationships between meteorological parameters and criteria air pollutants in three megacities in China. Environmental Research, 140, 242–254. https://doi.org/10.1016/j.envres.2015.04.004
Zhang, Q., Mao, X., Wang, Z., Tan, Y., Zhang, Z., Wu, Y., & Gao, Y. (2023). Impact of the emergency response to COVID-19 on air quality and its policy implications: Evidence from 290 cities in China. Environmental Science & Policy, 145, 50–59. https://doi.org/10.1016/j.envsci.2023.04.009
Zhao, H., Zheng, Y., & Li, C. (2018). Spatiotemporal distribution of PM2.5 and O3 and their interaction during the summer and winter seasons in Beijing, China. Sustainability, 10(12), 4519. https://doi.org/10.3390/su10124519
Zhao, S., Yu, Y., Yin, D., He, J., Liu, N., Qu, J., & Xiao, J. (2016). Annual and diurnal variations of gaseous and particulate pollutants in 31 provincial capital cities based on in situ air quality monitoring data from China National Environmental Monitoring Center. Environment International, 86, 92–106. https://doi.org/10.1016/j.envint.2015.11.003
Zhao, 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 and Technology Letters, 7(6), 402–408. https://doi.org/10.1021/acs.estlett.0c00304
Zheng, 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), 2895–2097. https://doi.org/10.5194/essd-13-2895-2021
Zheng, H., Kong, S., Chen, N., Yan, Y., Liu, D., Zhu, B., Xu, K., Cao, W., Ding, Q., Lan, B., Zhang, Z., Zheng, M., Fan, Z., Cheng, Y., Zheng, S., Yao, L., Bai, Y., Zhao, T., & Qi, S. (2020). Significant changes in the chemical compositions and sources of PM2.5 in Wuhan since the city lockdown as COVID-19. Science of the Total Environment, 739, 140000. https://doi.org/10.1016/j.scitotenv.2020.140000
Zhu, Y., Xie, J., Huang, F., & Cao, L. (2020). The mediating effect of air quality on the association between human mobility and COVID-19 infection in China. Environmental Research, 189, 109911. https://doi.org/10.1016/j.envres.2020.109911
Allison, L. S. (2020). Role of the terrestrial biosphere in atmospheric chemistry and climate. Accounts of Chemical Research, 53(7), 1260–1268. https://doi.org/10.1021/acs.accounts.0c00116
Bagherinia, M., Bodaghpour, S., Karimi, N., Ghasempour, F., Bilal, M., & Mhawish, A. (2023). Spatio-temporal air quality assessment in Tehran, Iran, during the COVID-19 lockdown periods. Geocarto International, 38(1), 2169374. https://doi.org/10.1080/10106049.2023.2169374
Bao, R., & Zhang, A. (2020). Does lockdown reduce air pollution? Evidence from 44 cities in northern China. Science of the Total Environment, 731, 139052. https://doi.org/10.1016/j.scitotenv.2020.139052
Cai, W., Wang, H., Wu, C., Lu, K., Peng, Z., & He, H. (2021). Characterizing the interruption-recovery patterns of urban air pollution under the COVID-19 lockdown in China. Building and Environment, 205, 108231. https://doi.org/10.1016/j.buildenv.2021.108231
Cao, X., Liu, X., Hadiatullah, H., Xu, Y., Zhang, X., Cyrys, J., Zimmermann, R., & Adam, T. (2022). Investigation of COVID-19-related lockdowns on the air pollution changes in Augsburg in 2020, Germany. Atmospheric Pollution Research, 13(9), 101536. https://doi.org/10.1016/j.apr.2022.101536
Chen, Y., Bai, Y., Liu, H., Alatalo, J. M., & Jiang, B. (2020). Temporal variations in ambient air quality indicators in Shanghai municipality, China. Scientific Reports, 10(1), 11350. https://doi.org/10.1038/s41598-020-68201-0
Chen, Z., Hao, X., Zhang, X., & Chen, F. (2021). Have traffic restrictions improved air quality? A shock from COVID-19. Journal of Cleaner Production, 279, 123622. https://doi.org/10.1016/j.jclepro.2020.123622
Chu, 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.2020.06.031
Coates, J., Mar, K. A., Ojha, N., & Butler, T. M. (2016). The influence of temperature on ozone production under varying NOx conditions – a modelling study. Atmospheric Chemistry and Physics, 16(18), 11601–11615. https://doi.org/10.5194/acp-16-11601-2016
Cooper, M. J., Martin, R. V., Hammer, M. S., Levelt, P. F., Veefkind, P., Lamsal, L. N., Krotkov, N. A., Brook, J. R., & McLinden, C. A. (2022). Global fine-scale changes in ambient NO2 during COVID-19 lockdowns. Nature, 601(7893), 380–387. https://doi.org/10.1038/s41586-021-04229-0
Dong, X., Zheng, X., Wang, C., Zeng, J., & Zhang, L. (2022). Air pollution rebound and different recovery modes during the period of easing COVID-19 restrictions. Science of the Total Environment, 843, 156942. https://doi.org/10.1016/j.scitotenv.2022.156942
Filonchyk, M., & Peterson, M. (2020). Air quality changes in Shanghai, China, and the surrounding urban agglomeration during the COVID-19 lockdown. Journal of Geovisualization and Spatial Analysis, 4(2), 22. https://doi.org/10.1007/s41651-020-00064-5
Gao, C., Zhang, F., Fang, D., Wang, Q., & Liu, M. (2023). Spatial characteristics of change trends of air pollutants in Chinese urban areas during 2016–2020: The impact of air pollution controls and the COVID-19 pandemic. Atmospheric Research, 283, 106539. https://doi.org/10.1016/j.atmosres.2022.106539
Grange, S. K., Lee, J. D., Drysdale, W. S., Lewis, A. C., Hueglin, C., Emmenegger, L., & Carslaw, D. C. (2021). COVID-19 lockdowns highlight a risk of increasing ozone pollution in European urban areas. Atmospheric Chemistry and Physics, 21(5), 4169–4185. https://doi.org/10.5194/acp-21-4169-2021
Guo, Q., He, Z., & Wang, Z. (2023). Change in air quality during 2014–2021 in Jinan City in China and its influencing factors. Toxics, 11(3), 210. https://doi.org/10.3390/toxics11030210
Hammad, H. M., Nauman, H. M. F., Abbas, F., Jawad, R., Farhad, W., Shahid, M., Bakhat, H. F., Farooque, A. A., Mubeen, M., Fahad, S., & Cerda, A. (2023). Impacts of COVID-19 pandemic on environment, society, and food security. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-023-25714-1
Han, J., Yin, J., Wu, X., Wang, D., & Li, C. (2023). Environment and COVID-19 incidence: A critical review. Journal of Environmental Sciences, 124, 933–951. https://doi.org/10.1016/j.jes.2022.02.016
Harapan, H., Itoh, N., Yufika, A., Winardi, W., Keam, S., Te, H., Megawati, D., Hayati, Z., Wagner, A. L., & Mudatsir, M. (2020). Coronavirus disease 2019 (COVID-19): A literature review. Journal of Infection and Public Health, 13(5), 667–673. https://doi.org/10.1016/j.jiph.2020.03.019
Hasnain, A., Hashmi, M. Z., Bhatti, U. A., Nadeem, B., Wei, G., Zha, Y., & Sheng, Y. (2021). Assessment of air pollution before, during and after the COVID-19 pandemic lockdown in Nanjing, China. Atmosphere, 12, 743. https://doi.org/10.3390/atmos12060743
He, G., Pan, Y., & Tanaka, T. (2020). The short-term impacts of COVID-19 lockdown on urban air pollution in China. Nature Sustainability, 3(12), 1005–1011. https://doi.org/10.1038/s41893-020-0581-y
Huang, C., Wang, T., Niu, T., Han, J., Li, M., Zhang, N., Liu, H., & Ma, C. (2021). Study on the causes of heavy pollution in Shenyang based on the contribution of natural conditions, physical processes, and anthropogenic emissions. Atmospheric Pollution Research, 12(4), 101224. https://doi.org/10.1016/j.apr.2021.101224
Huang, 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, 8(2), nwaa137. https://doi.org/10.1093/nsr/nwaa137
Huang, Y., & Li, R. (2022). The lockdown, mobility, and spatial health disparities in COVID-19 pandemic: A case study of New York City. Cities, 122, 103549. https://doi.org/10.1016/j.cities.2021.103549
Jia, H., Zang, S., Zhang, L., Yakovleva, E., Sun, H., & Sun, L. (2023). Spatiotemporal characteristics and socioeconomic factors of PM2.5 heterogeneity in mainland China during the COVID-19 epidemic. Chemosphere, 331, 138785. https://doi.org/10.1016/j.chemosphere.2023.138785
Kulkarni, P. S., Bortoli, D., & Silva, A. M. (2013). Nocturnal surface ozone enhancement and trend over urban and suburban sites in Portugal. Atmospheric Environment, 71, 251–259. https://doi.org/10.1016/j.atmosenv.2013.01.051
Kumar, A., Dhakhwa, S., & Dikshit, A. K. (2022). Comparative evaluation of fitness of interpolation techniques of ArcGIS using leave-one-out scheme for air quality mapping. Journal of Geovisualization and Spatial Analysis, 6(1), 9. https://doi.org/10.1007/s41651-022-00102-4
Le, 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, 369(6504), 702–706. https://doi.org/10.1126/science.abb7431
Li, D., & Lasenby, J. (2023). Investigating impacts of COVID-19 on urban mobility and emissions. Cities, 135, 104246. https://doi.org/10.1016/j.cities.2023.104246
Li, 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 of the United States of America, 116(2), 422–427. https://doi.org/10.1073/pnas.1812168116
Li, K., Ni, R., Jiang, T., Tian, Y., Zhang, X., Li, C., & Xie, C. (2022). The regional impact of the COVID-19 lockdown on the air quality in Ji’nan, China. Scientific Reports, 12(1), 12099. https://doi.org/10.1038/s41598-022-16105-6
Li, 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.2020.139282
Liang, Q., Liu, S., Yin, J., Han, Q., Zhang, W., & Niu, J. (2023). Spatial–temporal characteristics and influencing mechanisms of air quality index by considering COVID-19 in Yunnan, Southeastern Tibetan Plateau. Atmosphere, 14(2), 378. https://doi.org/10.3390/atmos14020378
Liu, 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 and Technology Letters, 7(11), 779–786. https://doi.org/10.1021/acs.estlett.0c00511
Llaguno-Munitxa, M., & Bou-Zeid, E. (2023). Role of vehicular emissions in urban air quality: The COVID-19 lockdown experiment. Transportation Research Part D: Transport and Environment, 115, 103580. https://doi.org/10.1016/j.trd.2022.103580
Luo, L., Bai, X., Lv, Y., Liu, S., Guo, Z., Liu, W., Hao, Y., Sun, Y., Hao, J., Zhang, K., Zhao, H., Lin S., Zhao, S., Xiao, Y., Yang, J., & Tian, H. (2022). Exploring the driving factors of haze events in Beijing during Chinese New Year holidays in 2020 and 2021 under the influence of COVID-19 pandemic. Science of the Total Environment, 859(1), 160172. https://doi.org/10.1016/j.scitotenv.2022.160172
Ma, Q., Wang, J., Xiong, M., & Zhu, L. (2023). Air Quality Index (AQI) did not improve during the COVID-19 lockdown in Shanghai, China, in 2022, based on ground and TROPOMI observations. Remote Sensing, 15(5), 1295. https://doi.org/10.3390/rs15051295
Ma, Y., Wang, M., Wang, S., Wang, Y., Feng, L., & Wu, K. (2021). Air pollutant emission characteristics and HYSPLIT model analysis during heating period in Shenyang, China. Environmental Monitoring and Assessment, 193(1), 9. https://doi.org/10.1007/s10661-020-08767-4
Mamtimin, A., Wang, Y., Zhao, T., Sayit, H., Yang, F., Huo, W., Zhou, C., & Gao, J. (2022). Impacts of winter and summer COVID-19 lockdowns on urban air quality in Urumqi, Northwest China. Frontiers in Environmental Science, 10, 910579. https://doi.org/10.3389/fenvs.2022.910579
Mo, Z., Huang, J., Chen, Z., Zhou, B., Zhu, K., Liu, H., Mu, Y., Zhang, D., & Wang, S. (2021). Cause analysis of PM2.5 pollution during the COVID-19 lockdown in Nanning, China. Scientific Reports, 11(1), 1–13. https://doi.org/10.1038/s41598-021-90617-5
Pushpawela, B., Shelton, S., Liyanage, G., Jayasekara, S., Rajapaksha, D., Jayasundara, A., & Jayasuriya, L. D. (2023). Changes of air pollutants in urban cities during the COVID-19 lockdown-Sri Lanka. Aerosol and Air Quality Research, 23(3), 220223. https://doi.org/10.4209/aaqr.220223
Ren, Y., Guan, X., Zhang, Q., Li, L., Tao, C., Ren, S., Wang, Q., & Wang, W. (2023). A machine learning-based study on the impact of COVID-19 on three kinds of pollution in Beijing-Tianjin-Hebei region. Science of the Total Environment, 884, 163190. https://doi.org/10.1016/j.scitotenv.2023.163190
Rupakheti, D., Yin, X., Rupakheti, M., Zhang, Q., Li, P., Rai, M., & Kang, S. (2021). Spatio-temporal characteristics of air pollutants over Xinjiang, northwestern China. Environmental Pollution, 268, 115907. https://doi.org/10.1016/j.envpol.2020.115907
Sbai, S. E., Mejjad, N., Norelyaqine, A., & Bentayeb, F. (2021). Air quality change during the COVID-19 pandemic lockdown over the Auvergne-Rhone-Alpes region, France. Air Quality, Atmosphere and Health, 14(5), 617–628. https://doi.org/10.1007/s11869-020-00965-w
Sekar, A., Jasna, R. S., Binoy, B. V., Mohan, P., & Kuttiparichel Varghese, G. (2023). Air quality change and public perception during the COVID-19 lockdown in India. Gondwana Research, 114, 15–29. https://doi.org/10.1016/j.gr.2022.04.023
Sharma, S., Zhang, M., Anshika, Gao, J., Zhang, H., & Kota, S. H. (2020). Effect of restricted emissions during COVID-19 on air quality in India. Science of the Total Environment, 728, 138878. https://doi.org/10.1016/j.scitotenv.2020.138878
Sicard, P., De Marco, A., Agathokleous, E., Feng, Z., Xu, X., Paoletti, E., Rodriguez, J. J. D., & Calatayud, V. (2020). Amplified ozone pollution in cities during the COVID-19 lockdown. Science of the Total Environment, 735, 139542. https://doi.org/10.1016/j.scitotenv.2020.139542
Singh, V., Singh, S., Biswal, A., Kesarkar, A.P., Mor, S., & Ravindra, K. (2020). Diurnal and temporal changes in air pollution during COVID-19 strict lockdown over different regions of India. Environmental Pollution, 266(Part 3), 115368. https://doi.org/10.1016/j.envpol.2020.115368
Song, Y., Li, Z., Liu, J., Yang, T., Zhang, M., & Pang, J. (2021). The effect of environmental regulation on air quality in China: A natural experiment during the COVID-19 pandemic. Atmospheric Pollution Research, 12(4), 21–30. https://doi.org/10.1016/j.apr.2021.02.010
Vadiati, M., Ghasemi, L., Samani, S., Islam, M. A., Ahmadi, A., Khaleghi, S., Movarej, M., Gorgij, A. D., Kisi, O., Davoodi, S., Dhama, K., Tiwari, A., & Bhattacharya, P. (2023). A sustainable trend in COVID-19 research: An environmental perspective. Frontiers in Environmental Science, 11, 1104679. https://doi.org/10.3389/fenvs.2023.1104679
Wang, H., Miao, Q., Shen, L., Yang, Q., Wu, Y., & Wei, H. (2021a). Air pollutant variations in Suzhou during the 2019 novel coronavirus (COVID-19) lockdown of 2020: High time-resolution measurements of aerosol chemical compositions and source apportionment. Environmental Pollution, 271, 116298. https://doi.org/10.1016/j.envpol.2020.116298
Wang, J., Shi, W., Xue, K., Wu, T., & Fang, C. (2023). Analysis of the impact of meteorological factors on ambient air quality during the COVID-19 lockdown in Jilin City in 2022. Atmosphere, 14(2), 400. https://doi.org/10.3390/atmos14020400
Wang, L., Li, M., Yu, S., Chen, X., Li, Z., Zhang, Y., Jiang, L., Xia, Y., Li, J., Liu, W., Li, P., Lichtfouse, E., Rosenfeld, D., & Seinfeld, J. H. (2020c). Unexpected rise of ozone in urban and rural areas, and sulfur dioxide in rural areas during the coronavirus city lockdown in Hangzhou, China: implications for air quality. Environmental Chemistry Letters, 18(368), 1713–1723. https://doi.org/10.1007/s10311-020-01028-3
Wang, L., Zhao, W., Luo, P., He, Q., Zhang, W., Dong, C., & Zhang, Y. (2024). Environmentally persistent free radicals in PM2.5 from a typical Chinese industrial city during COVID-19 lockdown: The unexpected contamination level variation. Journal of Environmental Sciences, 135, 424–432. https://doi.org/10.1016/j.jes.2022.08.024
Wang, M., Liu, F., & Zheng, M. (2021b). Air quality improvement from COVID-19 lockdown: evidence from China. Air Quality, Atmosphere and Health, 14(4), 591–604. https://doi.org/10.1007/s11869-020-00963-y
Wang, P., Chen, K., Zhu, S., Wang, P., & Zhang, H. (2020a). 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.2020.104814
Wang, X., & Zhang, R. (2020). How did air pollution change during the COVID-19 outbreak in China? Bulletin of the American Meteorological Society, 101(10), E1645–E1652. https://doi.org/10.1175/BAMS-D-20-0102.1
Wang, Y., & Ge, Q. (2023). The positive impact of the Omicron pandemic lockdown on air quality and human health in cities around Shanghai. Environment, Development and Sustainability. https://doi.org/10.1007/s10668-023-03071-w
Wang, Y., Duan, X., Liang, T., Wang, L., & Wang, L. (2022). Analysis of spatio-temporal distribution characteristics and socioeconomic drivers of urban air quality in China. Chemosphere, 291, 132799. https://doi.org/10.1016/j.chemosphere.2021.132799
Wang, Y., Gao, W., Wang, S., Song, T., Gong, Z., Ji, D., Wang, L., Liu, Z., Tang, G., Huo, Y., Tian, S., Li, J., Li, M., Yang, Y., Chu, B., Petäjä, T., Kerminen, V. M., He, H., Hao, J., ... Zhang, Y. (2020d). Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017. National Science Review, 7(8), 1331–1339. https://doi.org/10.1093/nsr/nwaa032
Wang, Y., Wen, Y., Wang, Y., Zhang, S., Zhang, K. M., Zheng, H., Xing, J., Wu, Y., & Hao, J. (2020b). Four-month changes in air quality during and after the COVID-19 lockdown in six megacities in China. Environmental Science and Technology Letters, 7(11), 802–808. https://doi.org/10.1021/acs.estlett.0c00605
Wang, Z., Li, Y., Chen, T., Li, L., Liu, B., Zhang, D., Sun, F., Wei, Q., Jiang, L., & Pan, L. (2015). Changes in atmospheric composition during the 2014 APEC conference in Beijing. Journal of Geophysical Research: Atmospheres, 120(24), 12695–12707. https://doi.org/10.1002/2015JD023652
Wong, Y. J., Yeganeh, A., Chia, M. Y., Shiu, H. Y., Ooi, M. C. G., Chang, J. H. W., Shimizu, Y., Ryosuke, H., Try, S., & Elbeltagi, A. (2023). Quantification of COVID-19 impacts on NO2 and O3: Systematic model selection and hyperparameter optimization on AI-based meteorological-normalization methods. Atmospheric Environment, 301, 119677. https://doi.org/10.1016/j.atmosenv.2023.119677
World Health Organization. (2020). Introduction to COVID-19: Methods for detection, prevention, response and control. https://openwho.org/courses/introduction-to-ncov
Xiao, K., Wang, Y., Wu, G., Fu, B., & Zhu, Y. (2018). Spatiotemporal characteristics of air pollutants (PM10, PM2.5, SO2, NO2, O3, and CO) in the inland basin city of Chengdu, southwest China. Atmosphere, 9(2), 74. https://doi.org/10.3390/atmos9020074
Xu, K., Cui, K., Young, L. H., Wang, Y. F., Hsieh, Y. K., Wan, S., & Zhang, J. (2020). Air quality index, indicatory air pollutants and impact of COVID-19 event on the air quality near central China. Aerosol and Air Quality Research, 20(6), 1204–1221. https://doi.org/10.4209/aaqr.2020.04.0139
Yang, H., Peng, Q., Zhou, J., Song, G., & Gong, X. (2020). The unidirectional causality influence of factors on PM2.5 in Shenyang city of China. Scientific Reports, 10(1), 8403. https://doi.org/10.1038/s41598-020-65391-5
Yang, J., Ji, Q., Pu, H., Dong, X., & Yang, Q. (2023). How does COVID-19 lockdown affect air quality: Evidence from Lanzhou, a large city in Northwest China. Urban Climate, 49, 101533. https://doi.org/10.1016/j.uclim.2023.101533
Yao, Y., Wang, Y., Yu, H., & Qin, H. (2021). Analysis on the influencing factors of air quality during the Spring Festival in Beijing in 2020. Environment, Development and Sustainability, 46(2), 107–114. https://doi.org/10.19758/j.cnki.issn1673-288x.202102107
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.2021.117899
Zeng, J., & Wang, C. (2022). Temporal characteristics and spatial heterogeneity of air quality changes due to the COVID-19 lockdown in China. Resources, Conservation and Recycling, 181, 106223. https://doi.org/10.1016/j.resconrec.2022.106223
Zhang, C., & Stevenson, D. (2022). Characteristic changes of ozone and its precursors in London during COVID-19 lockdown and the ozone surge reason analysis. Atmospheric Environment, 273, 118980. https://doi.org/10.1016/j.atmosenv.2022.118980
Zhang, H., Wang, Y., Hu, J., Ying, Q., & Hu, X. M. (2015). Relationships between meteorological parameters and criteria air pollutants in three megacities in China. Environmental Research, 140, 242–254. https://doi.org/10.1016/j.envres.2015.04.004
Zhang, Q., Mao, X., Wang, Z., Tan, Y., Zhang, Z., Wu, Y., & Gao, Y. (2023). Impact of the emergency response to COVID-19 on air quality and its policy implications: Evidence from 290 cities in China. Environmental Science & Policy, 145, 50–59. https://doi.org/10.1016/j.envsci.2023.04.009
Zhao, H., Zheng, Y., & Li, C. (2018). Spatiotemporal distribution of PM2.5 and O3 and their interaction during the summer and winter seasons in Beijing, China. Sustainability, 10(12), 4519. https://doi.org/10.3390/su10124519
Zhao, S., Yu, Y., Yin, D., He, J., Liu, N., Qu, J., & Xiao, J. (2016). Annual and diurnal variations of gaseous and particulate pollutants in 31 provincial capital cities based on in situ air quality monitoring data from China National Environmental Monitoring Center. Environment International, 86, 92–106. https://doi.org/10.1016/j.envint.2015.11.003
Zhao, 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 and Technology Letters, 7(6), 402–408. https://doi.org/10.1021/acs.estlett.0c00304
Zheng, 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), 2895–2097. https://doi.org/10.5194/essd-13-2895-2021
Zheng, H., Kong, S., Chen, N., Yan, Y., Liu, D., Zhu, B., Xu, K., Cao, W., Ding, Q., Lan, B., Zhang, Z., Zheng, M., Fan, Z., Cheng, Y., Zheng, S., Yao, L., Bai, Y., Zhao, T., & Qi, S. (2020). Significant changes in the chemical compositions and sources of PM2.5 in Wuhan since the city lockdown as COVID-19. Science of the Total Environment, 739, 140000. https://doi.org/10.1016/j.scitotenv.2020.140000
Zhu, Y., Xie, J., Huang, F., & Cao, L. (2020). The mediating effect of air quality on the association between human mobility and COVID-19 infection in China. Environmental Research, 189, 109911. https://doi.org/10.1016/j.envres.2020.109911