{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T04:01:35Z","timestamp":1778212895242,"version":"3.51.4"},"reference-count":127,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,10]],"date-time":"2022-02-10T00:00:00Z","timestamp":1644451200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UID\/EQU\/00511\/2020"],"award-info":[{"award-number":["UID\/EQU\/00511\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>With the emergence of the COVID-19 pandemic, several governments imposed severe restrictions on socio-economic activities, putting most of the world population into a general lockdown in March 2020. Although scattered, studies on this topic worldwide have rapidly emerged in the literature. Hence, this systematic review aimed to identify and discuss the scientifically validated literature that evaluated the impact of the COVID-19 pandemic and associated restrictions on air quality. Thus, a total of 114 studies that quantified the impact of the COVID-19 pandemic on air quality through monitoring were selected from three databases. The most evaluated countries were India and China; all the studies intended to evaluate the impact of the pandemic on air quality, mainly concerning PM10, PM2.5, NO2, O3, CO, and SO2. Most of them focused on the 1st lockdown, comparing with the pre- and post-lockdown periods and usually in urban areas. Many studies conducted a descriptive analysis, while others complemented it with more advanced statistical analysis. Although using different methodologies, some studies reported a temporary air quality improvement during the lockdown. More studies are still needed, comparing different lockdown and lifting periods and, in other areas, for a definition of better-targeted policies to reduce air pollution.<\/jats:p>","DOI":"10.3390\/ijerph19041950","type":"journal-article","created":{"date-parts":[[2022,2,10]],"date-time":"2022-02-10T04:42:27Z","timestamp":1644468147000},"page":"1950","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":45,"title":["Impact of COVID-19 Pandemic on Air Quality: A Systematic Review"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2847-7698","authenticated-orcid":false,"given":"Ana Catarina T.","family":"Silva","sequence":"first","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"ALiCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4163-0936","authenticated-orcid":false,"given":"Pedro T. B. S.","family":"Branco","sequence":"additional","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"ALiCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4139-673X","authenticated-orcid":false,"given":"Sofia I. V.","family":"Sousa","sequence":"additional","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"ALiCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,10]]},"reference":[{"key":"ref_1","unstructured":"WHO (World Health Organization) (2021, February 13). Ambient (Outdoor) Air Pollution. Available online: https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/ambient-(outdoor)-air-quality-and-health."},{"key":"ref_2","unstructured":"Health Effects Institute (2019). State of Global Air 2019, Health Effects Institute."},{"key":"ref_3","first-page":"157","article-title":"WHO declares COVID-19 a pandemic","volume":"91","author":"Cucinotta","year":"2020","journal-title":"Acta Biomedica"},{"key":"ref_4","unstructured":"Blavatnik School of Government (2022). COVID-19 Government Response Tracker, Blavatnik School of Government."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"142533","DOI":"10.1016\/j.scitotenv.2020.142533","article-title":"Effects of COVID-19 lockdown on global air quality and health","volume":"755","author":"Liu","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"101061","DOI":"10.1016\/j.jth.2021.101061","article-title":"Effect of COVID-19 on air quality and pollution in different countries","volume":"21","author":"Albayati","year":"2021","journal-title":"J. Transp. Health"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"140573","DOI":"10.1016\/j.scitotenv.2020.140573","article-title":"Coronavirus lockdown helped the environment to bounce back","volume":"742","author":"Arora","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1403","DOI":"10.1007\/s11869-020-00894-8","article-title":"A brief review of socio-economic and environmental impact of COVID-19","volume":"13","author":"Bashir","year":"2020","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e04965","DOI":"10.1016\/j.heliyon.2020.e04965","article-title":"Environmental effects of COVID-19 pandemic and potential strategies of sustainability","volume":"6","author":"Rume","year":"2020","journal-title":"Heliyon"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"142391","DOI":"10.1016\/j.scitotenv.2020.142391","article-title":"The COVID-19 pandemic: Impacts on cities and major lessons for urban planning, design, and management","volume":"749","author":"Sharifi","year":"2020","journal-title":"Sci. Total. Environ."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Moher, D., Liberati, A., Tetzlaff, J., Altman, D.G., and Group, T.P. (2009). Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med., 6.","DOI":"10.1371\/journal.pmed.1000097"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"141322","DOI":"10.1016\/j.scitotenv.2020.141322","article-title":"Early spring near-surface ozone in Europe during the COVID-19 shutdown: Meteorological effects outweigh emission changes","volume":"747","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Piccoli, A., Agresti, V., Balzarini, A., Bedogni, M., Bonanno, R., Collino, E., Colzi, F., Lacavalla, M., Lanzani, G., and Pirovano, G. (2020). Modeling the effect of COVID-19 lockdown on mobility and NO2 concentration in the Lombardy region. Atmosphere, 11.","DOI":"10.3390\/atmos11121319"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Vultaggio, M., Varrica, D., and Alaimo, M.G. (2020). Impact on air quality of the COVID-19 lockdown in the urban area of Palermo (Italy). Int. J. Environ. Res. Public Health, 17.","DOI":"10.3390\/ijerph17207375"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"117153","DOI":"10.1016\/j.envpol.2021.117153","article-title":"Increased ozone pollution alongside reduced nitrogen dioxide concentrations during Vienna\u2019s first COVID-19 lockdown: Significance for air quality management","volume":"284","author":"Brancher","year":"2021","journal-title":"Environ. Pollut."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Dinoi, A., Gulli, D., Ammoscato, I., Calidonna, C., and Contini, D. (2021). Impact of the coronavirus pandemic lockdown on atmospheric nanoparticle concentrations in two sites of Southern Italy. Atmosphere, 12.","DOI":"10.3390\/atmos12030352"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"110515","DOI":"10.1016\/j.envres.2020.110515","article-title":"The impact of COVID-19 on air quality levels in Portugal: A way to assess traffic contribution","volume":"193","author":"Gama","year":"2021","journal-title":"Environ. Res."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Lonati, G., and Riva, F. (2021). Regional scale impact of the COVID-19 lockdown on air quality: Gaseous pollutants in the po valley, northern Italy. Atmosphere, 12.","DOI":"10.3390\/atmos12020264"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"115900","DOI":"10.1016\/j.envpol.2020.115900","article-title":"Understanding the true effects of the COVID-19 lockdown on air pollution by means of machine learning","volume":"274","author":"Grange","year":"2021","journal-title":"Environ. Pollut."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1007\/s12076-021-00267-4","article-title":"Lockdown measures and air quality: Evidence from Italian provinces","volume":"14","author":"Malpede","year":"2021","journal-title":"Lett. Spat. Resour. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"111018","DOI":"10.1016\/j.envres.2021.111018","article-title":"The impacts of COVID-19 lockdown on PM10 and SO2 concentrations and association with human mobility across Turkey","volume":"197","author":"Orak","year":"2021","journal-title":"Environ. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"129027","DOI":"10.1016\/j.chemosphere.2020.129027","article-title":"Impact of SARS-CoV-2 lockdown and de-escalation on air-quality parameters","volume":"265","author":"Viteri","year":"2021","journal-title":"Chemosphere"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"139179","DOI":"10.1016\/j.scitotenv.2020.139179","article-title":"Assessing air quality changes in large cities during COVID-19 lockdowns: The impacts of traffic-free urban conditions in Almaty, Kazakhstan","volume":"730","author":"Kerimray","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"102382","DOI":"10.1016\/j.scs.2020.102382","article-title":"Temporary reduction in fine particulate matter due to \u2018anthropogenic emissions switch-off\u2019 during COVID-19 lockdown in Indian cities","volume":"62","author":"Kumar","year":"2020","journal-title":"Sustain. Cities Soc."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"84021","DOI":"10.1088\/1748-9326\/aba3a2","article-title":"The impact of COVID-19 control measures on air quality in China","volume":"15","author":"Silver","year":"2020","journal-title":"Environ. Res. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"100729","DOI":"10.1016\/j.uclim.2020.100729","article-title":"COVID-19 lockdown and air quality of SAFAR-India metro cities","volume":"34","author":"Yadav","year":"2020","journal-title":"Urban Clim."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1016\/j.jes.2021.01.022","article-title":"Assessment of health benefit of PM2.5 reduction during COVID-19 lockdown in China and separating contributions from anthropogenic emissions and meteorology","volume":"115","author":"Bai","year":"2021","journal-title":"J. Environ. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"346","DOI":"10.1016\/j.jes.2020.06.031","article-title":"Significant concurrent decrease in PM2.5 and NO2 concentrations in China during COVID-19 epidemic","volume":"99","author":"Chu","year":"2021","journal-title":"J. Environ. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"100010","DOI":"10.1016\/j.hazl.2020.100010","article-title":"Comprehensive study on impact assessment of lockdown on overall ambient air quality amid COVID-19 in Delhi and its NCR, India","volume":"2","author":"Garg","year":"2021","journal-title":"J. Hazard. Mater. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"64","DOI":"10.3389\/fenvs.2021.654651","article-title":"Changes in air pollution following the COVID-19 epidemic in Northern China: The role of meteorology","volume":"9","author":"Xian","year":"2021","journal-title":"Front. Environ. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"23405","DOI":"10.1007\/s11356-020-12164-2","article-title":"Changes in the concentration of air pollutants before and after the COVID-19 blockade period and their correlation with vegetation coverage","volume":"28","author":"Zhou","year":"2021","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"140931","DOI":"10.1016\/j.scitotenv.2020.140931","article-title":"Reductions in traffic-related black carbon and ultrafine particle number concentrations in an urban neighborhood during the COVID-19 pandemic","volume":"742","author":"Hudda","year":"2020","journal-title":"Sci. Total. Environ."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"139087","DOI":"10.1016\/j.scitotenv.2020.139087","article-title":"COVID-19 pandemic: Impacts on the air quality during the partial lockdown in S\u00e3o Paulo state, Brazil","volume":"730","author":"Nakada","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1007\/s11869-020-00960-1","article-title":"Impacts of the COVID-19 lockdown on air quality and its association with human mortality trends in megapolis Mexico City","volume":"14","author":"Roy","year":"2021","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"141592","DOI":"10.1016\/j.scitotenv.2020.141592","article-title":"Spatiotemporal impacts of COVID-19 on air pollution in California, USA","volume":"750","author":"Liu","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"141129","DOI":"10.1016\/j.scitotenv.2020.141129","article-title":"Implications for air quality management of changes in air quality during lockdown in Auckland (New Zealand) in response to the 2020 SARS-CoV-2 epidemic","volume":"746","author":"Patel","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"118386","DOI":"10.1016\/j.atmosenv.2021.118386","article-title":"Impact of lockdown during the COVID-19 outbreak on multi-scale air quality","volume":"254","author":"Bray","year":"2021","journal-title":"Atmos. Environ."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1089","DOI":"10.1080\/10473289.1994.10467303","article-title":"Detecting and tracking changes in ozone air quality","volume":"44","author":"Rao","year":"1994","journal-title":"Air Waste"},{"key":"ref_39","first-page":"1","article-title":"Global air quality and COVID-19 pandemic: Do we breathe cleaner air?","volume":"21","author":"Torkmahalleh","year":"2021","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"139658","DOI":"10.1016\/j.scitotenv.2020.139658","article-title":"COVID-19\u2019s impact on the atmospheric environment in the Southeast Asia region","volume":"736","author":"Kanniah","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1007\/s11869-020-00888-6","article-title":"Fluctuations in environmental pollutants and air quality during the lockdown in the USA and China: Two sides of COVID-19 pandemic","volume":"13","author":"Shakoor","year":"2020","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"100719","DOI":"10.1016\/j.uclim.2020.100719","article-title":"Impact of lockdown on air quality over major cities across the globe during COVID-19 pandemic","volume":"34","author":"Kumari","year":"2020","journal-title":"Urban Clim."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"115042","DOI":"10.1016\/j.envpol.2020.115042","article-title":"Air quality during the COVID-19: PM2.5 analysis in the 50 most polluted capital cities in the world","volume":"266","year":"2020","journal-title":"Environ. Pollut."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"112166","DOI":"10.1016\/j.jenvman.2021.112166","article-title":"Public transit usage and air quality index during the COVID-19 lockdown","volume":"286","author":"Sahraei","year":"2021","journal-title":"J. Environ. Manag."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Skirien\u0117, A.F., and Stasi\u0161kien\u0117, \u017d. (2021). COVID-19 and air pollution: Measuring pandemic impact to air quality in five european countries. Atmosphere, 12.","DOI":"10.3390\/atmos12030290"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Solberg, S., Walker, S.-E., Schneider, P., and Guerreiro, C. (2021). Quantifying the impact of the COVID-19 lockdown measures on nitrogen dioxide levels throughout Europe. Atmosphere, 12.","DOI":"10.3390\/atmos12020131"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1080\/09603123.2020.1778646","article-title":"Impact of lockdown measures during COVID-19 on air quality\u2014A case study of India","volume":"32","author":"Kumari","year":"2020","journal-title":"Int. J. Environ. Health Res."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"115080","DOI":"10.1016\/j.envpol.2020.115080","article-title":"The impact of COVID-19 as a necessary evil on air pollution in India during the lockdown","volume":"266","author":"Shehzad","year":"2020","journal-title":"Environ. Pollut."},{"key":"ref_49","first-page":"242","article-title":"Impact of the COVID-19 lockdown on air quality and resulting public health benefits in the Mexico City Metropolitan Area","volume":"9","author":"Valdez","year":"2021","journal-title":"Front. Public Health"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"100200","DOI":"10.1016\/j.onehlt.2020.100200","article-title":"COVID-19 national lockdown in morocco: Impacts on air quality and public health","volume":"11","author":"Khomsi","year":"2020","journal-title":"One Health"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"115691","DOI":"10.1016\/j.envpol.2020.115691","article-title":"Improved air quality and associated mortalities in India under COVID-19 lockdown","volume":"268","author":"Naqvi","year":"2021","journal-title":"Environ. Pollut."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1080\/15275922.2020.1836082","article-title":"COVID-19 pandemic: An outlook on its impact on air quality and its association with environmental variables in major cities of Punjab and Chandigarh, India","volume":"22","author":"Sahoo","year":"2021","journal-title":"Environ. Forensics"},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Bai, Y., Zhou, Y., Alatalo, J., and Hughes, A. (2020). Changes in air quality during the first-level response to the COVID-19 pandemic in Shanghai Municipality, China. Sustainability, 12.","DOI":"10.3390\/su12218887"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"138878","DOI":"10.1016\/j.scitotenv.2020.138878","article-title":"Effect of restricted emissions during COVID-19 on air quality in India","volume":"728","author":"Sharma","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1007\/s11869-020-00963-y","article-title":"Air quality improvement from COVID-19 lockdown: Evidence from China","volume":"14","author":"Wang","year":"2021","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"145545","DOI":"10.1016\/j.scitotenv.2021.145545","article-title":"Impact of the COVID-19 pandemic on air pollution in Chinese megacities from the perspective of traffic volume and meteorological factors","volume":"773","author":"Gao","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1748","DOI":"10.4209\/aaqr.2020.06.0303","article-title":"Changes in air quality during the COVID-19 lockdown in Singapore and associations with human mobility trends","volume":"20","author":"Li","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"139085","DOI":"10.1016\/j.scitotenv.2020.139085","article-title":"The impact of COVID-19 partial lockdown on the air quality of the city of Rio de Janeiro, Brazil","volume":"729","author":"Dantas","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"110665","DOI":"10.1016\/j.envres.2020.110665","article-title":"Phase-wise analysis of the COVID-19 lockdown impact on aerosol, radiation and trace gases and associated chemistry in a tropical rural environment","volume":"194","author":"Jain","year":"2021","journal-title":"Environ. Res."},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Duc, H., Salter, D., Azzi, M., Jiang, N., Warren, L., Watt, S., Riley, M., White, S., Trieu, T., and Chang, L.T.-C. (2021). The effect of lockdown period during the COVID-19 pandemic on air quality in Sydney region, Australia. Int. J. Environ. Res. Public Health, 18.","DOI":"10.20944\/preprints202103.0126.v1"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1007\/s00128-020-02895-w","article-title":"21-day lockdown in India dramatically reduced air pollution indices in Lucknow and New Delhi, India","volume":"105","author":"Srivastava","year":"2020","journal-title":"Bull. Environ. Contam. Toxicol."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"118388","DOI":"10.1016\/j.atmosenv.2021.118388","article-title":"Impact of the COVID-19 Induced lockdown measures on PM2.5 concentration in USA","volume":"254","author":"Ghosal","year":"2021","journal-title":"Atmos. Environ."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"548","DOI":"10.1007\/s12517-021-06898-7","article-title":"Assessing the air quality of megacities during the COVID-19 pandemic lockdown: A case study from Makkah City, Saudi Arabia","volume":"14","author":"Morsy","year":"2021","journal-title":"Arab. J. Geosci."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"200459","DOI":"10.4209\/aaqr.2020.07.0459","article-title":"Investigating the implications of COVID-19 on PM2.5 in Pakistan","volume":"21","author":"Sipra","year":"2021","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"141105","DOI":"10.1016\/j.scitotenv.2020.141105","article-title":"Nonuniform impacts of COVID-19 lockdown on air quality over the United States","volume":"745","author":"Chen","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"1095","DOI":"10.46488\/NEPT.2020.v19i03.020","article-title":"Impact of the COVID-19 pandemic on the air quality in Delhi, India","volume":"19","author":"Goel","year":"2020","journal-title":"Nat. Environ. Pollut. Technol."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1007\/s00484-020-02019-3","article-title":"Pre-to-post lockdown impact on air quality and the role of environmental factors in spreading the COVID-19 cases\u2014A study from a worst-hit state of India","volume":"65","author":"Sahoo","year":"2021","journal-title":"Int. J. Biometeorol."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"105362","DOI":"10.1016\/j.atmosres.2020.105362","article-title":"COVID-19 pandemic in Wuhan: Ambient air quality and the relationships between criteria air pollutants and meteorological variables before, during, and after lockdown","volume":"250","author":"Sulaymon","year":"2021","journal-title":"Atmos. Res."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"111108","DOI":"10.1016\/j.envres.2021.111108","article-title":"How do pollutants change post-pandemic? Evidence from changes in five key pollutants in nine Chinese cities most affected by the COVID-19","volume":"197","author":"Wang","year":"2021","journal-title":"Environ. Res."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1007\/s11869-020-00918-3","article-title":"The impact of COVID-19 lockdown on the air quality of Eastern Province, Saudi Arabia","volume":"14","author":"Anil","year":"2021","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"125445","DOI":"10.1016\/j.jhazmat.2021.125445","article-title":"Rigorous quantification of statistical significance of the COVID-19 lockdown effect on air quality: The case from ground-based measurements in Ontario, Canada","volume":"413","author":"Lysy","year":"2021","journal-title":"J. Hazard. Mater."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"110607","DOI":"10.1016\/j.envres.2020.110607","article-title":"Improved ANFIS model for forecasting Wuhan City air quality and analysis COVID-19 lockdown impacts on air quality","volume":"194","author":"Fan","year":"2021","journal-title":"Environ. Res."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.jes.2020.07.029","article-title":"Changes in air pollution during COVID-19 lockdown in Spain: A multi-city study","volume":"101","year":"2021","journal-title":"J. Environ. Sci."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"1616","DOI":"10.1007\/s10668-021-01328-w","article-title":"How COVID-19 pandemic and partial lockdown decisions affect air quality of a city? The case of Istanbul, Turkey","volume":"24","author":"Celik","year":"2021","journal-title":"Environ. Dev. Sustain."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"223","DOI":"10.13075\/ijomeh.1896.01784","article-title":"Short-term health effects of air quality changes during the COVID-19 pandemic in the City of Novi Sad, the Republic of Serbia","volume":"34","author":"Dragic","year":"2021","journal-title":"Int. J. Occup. Med. Environ. Health"},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"110454","DOI":"10.1016\/j.envres.2020.110454","article-title":"Impact of COVID-19 lockdown on air quality in the Poland, Eastern Europe","volume":"198","author":"Filonchyk","year":"2021","journal-title":"Environ. Res."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"18204","DOI":"10.1007\/s10668-021-01434-9","article-title":"Short-term impacts of air pollutants in three megacities of India during COVID-19 lockdown","volume":"23","author":"Ganguly","year":"2021","journal-title":"Environ. Dev. Sustain."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"115682","DOI":"10.1016\/j.envpol.2020.115682","article-title":"Quantifying road traffic impact on air quality in urban areas: A Covid19-induced lockdown analysis in Italy","volume":"267","author":"Gualtieri","year":"2020","journal-title":"Environ. Pollut."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"21621","DOI":"10.1007\/s11356-020-11808-7","article-title":"Impact of COVID-19 lockdown on ambient air quality in megacities of India and implication for air pollution control strategies","volume":"28","author":"Ravindra","year":"2021","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"102418","DOI":"10.1016\/j.apgeog.2021.102418","article-title":"Impact of the COVID-19 lockdown on air quality in the Delhi Metropolitan Region","volume":"128","author":"Roy","year":"2021","journal-title":"Appl. Geogr."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"111052","DOI":"10.1016\/j.envres.2021.111052","article-title":"Does air pollution upsurge in megacities after COVID-19 lockdown? A spatial approach","volume":"197","author":"Shehzad","year":"2021","journal-title":"Environ. Res."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"100791","DOI":"10.1016\/j.uclim.2021.100791","article-title":"Improved air quality during COVID-19 at an urban megacity over the Indo-Gangetic Basin: From stringent to relaxed lockdown phases","volume":"36","author":"Srivastava","year":"2021","journal-title":"Urban Clim."},{"key":"ref_83","doi-asserted-by":"crossref","unstructured":"SSu, Z., Duan, Z., Deng, B., Liu, Y., and Chen, X. (2021). Impact of the COVID-19 lockdown on air quality trends in Guiyang, Southwestern China. Atmosphere, 12.","DOI":"10.3390\/atmos12040422"},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"1071","DOI":"10.1007\/s11869-021-01000-2","article-title":"The influence of COVID-19 preventive measures on the air quality in Abu Dhabi (United Arab Emirates)","volume":"14","author":"Mohamed","year":"2021","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"144270","DOI":"10.1016\/j.scitotenv.2020.144270","article-title":"Assessing the impact of COVID-19 pandemic on urban transportation and air quality in Canada","volume":"765","author":"Tian","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"126475","DOI":"10.1016\/j.jclepro.2021.126475","article-title":"The impact of the COVID-19 outbreak on the air quality in China: Evidence from a quasi-natural experiment","volume":"296","author":"Zhang","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_87","doi-asserted-by":"crossref","unstructured":"Zhang, T., and Tang, M. (2021). The Impact of the COVID-19 pandemic on ambient air quality in China: A quasi-difference-in-difference approach. Int. J. Environ. Res. Public Health, 18.","DOI":"10.21203\/rs.3.rs-220044\/v1"},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"1793","DOI":"10.4209\/aaqr.2020.05.0205","article-title":"Impact of COVID-19 event on the air quality in Iran","volume":"20","author":"Broomandi","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"141978","DOI":"10.1016\/j.scitotenv.2020.141978","article-title":"Impact of COVID-19 lockdown on NO2, O3, PM2.5 and PM10 concentrations and assessing air quality changes in Baghdad, Iraq","volume":"754","author":"Hashim","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"140879","DOI":"10.1016\/j.scitotenv.2020.140879","article-title":"Response of major air pollutants to COVID-19 lockdowns in China","volume":"743","author":"Pei","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/s41207-020-00189-5","article-title":"What is the relationship between the coronavirus crisis and air pollution in Tunisia?","volume":"6","author":"Chekir","year":"2021","journal-title":"EuroMediterr. J. Environ. Integr."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"125397","DOI":"10.1016\/j.jclepro.2020.125397","article-title":"Assessment and offset of the adverse effects induced by PM2.5 from coal-fired power plants in China","volume":"286","author":"He","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.1038\/s41893-020-0581-y","article-title":"The short-term impacts of COVID-19 lockdown on urban air pollution in China","volume":"3","author":"He","year":"2020","journal-title":"Nat. Sustain."},{"key":"ref_94","doi-asserted-by":"crossref","unstructured":"Kar, S., Ghosh, I., Show, S., Sen, A., Gupta, T., Chowdhury, P., Chatterjee, T., and RoyChowdhury, A. (2021). Impact of coronavirus (COVID-19) outbreak on society, air quality, and economy in India: A study of three \u201cP\u201ds of sustainability in India. Sustainability, 13.","DOI":"10.3390\/su13052873"},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"109835","DOI":"10.1016\/j.envres.2020.109835","article-title":"Short-term exposure to ambient air quality of the most polluted Indian cities due to lockdown amid SARS-CoV-2","volume":"188","author":"Mahato","year":"2020","journal-title":"Environ. Res."},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"126674","DOI":"10.1016\/j.jclepro.2021.126674","article-title":"Effects of lockdown due to COVID-19 outbreak on air quality and anthropogenic heat in an industrial belt of India","volume":"297","author":"Pal","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"1269","DOI":"10.1007\/s13762-021-03142-3","article-title":"COVID-19 lockdown: A rare opportunity to establish baseline pollution level of air pollutants in a megacity, India","volume":"18","author":"Sahoo","year":"2021","journal-title":"Int. J. Environ. Sci. Technol."},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"8613","DOI":"10.1007\/s10668-020-00985-7","article-title":"Assessing the immediate impact of COVID-19 lockdown on the air quality of Kolkata and Howrah, West Bengal, India","volume":"23","author":"Sarkar","year":"2021","journal-title":"Environ. Dev. Sustain."},{"key":"ref_99","doi-asserted-by":"crossref","unstructured":"Seo, J., Jeon, H., Sung, U., and Sohn, J.-R. (2020). Impact of the COVID-19 outbreak on air quality in Korea. Atmosphere, 11.","DOI":"10.3390\/atmos11101137"},{"key":"ref_100","doi-asserted-by":"crossref","first-page":"696","DOI":"10.1080\/00207233.2020.1858578","article-title":"Air pollution in four Indian cities during the COVID-19 pandemic","volume":"78","author":"Tripathi","year":"2020","journal-title":"Int. J. Environ. Stud."},{"key":"ref_101","doi-asserted-by":"crossref","unstructured":"Boddin, D. (2016). The Role of Newly Industrialized Economies in Global Value Chains, International Monetary Fund.","DOI":"10.2139\/ssrn.2882642"},{"key":"ref_102","doi-asserted-by":"crossref","first-page":"140556","DOI":"10.1016\/j.scitotenv.2020.140556","article-title":"Impact of city lockdown on the air quality of COVID-19-hit of Wuhan city","volume":"742","author":"Lian","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_103","doi-asserted-by":"crossref","first-page":"127978","DOI":"10.1016\/j.chemosphere.2020.127978","article-title":"Impact of COVID-19 lockdown on air quality in Chandigarh, India: Understanding the emission sources during controlled anthropogenic activities","volume":"263","author":"Mor","year":"2021","journal-title":"Chemosphere"},{"key":"ref_104","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1016\/j.apr.2020.11.005","article-title":"Silver linings in the dark clouds of COVID-19: Improvement of air quality over India and Delhi metropolitan area from measurements and WRF-CHIMERE model simulations","volume":"12","author":"Dumka","year":"2021","journal-title":"Atmos. Pollut. Res."},{"key":"ref_105","doi-asserted-by":"crossref","first-page":"2592","DOI":"10.4209\/aaqr.2020.05.0262","article-title":"COVID-19 and air pollution in indian cities: World\u2019s most polluted cities","volume":"20","author":"Kumari","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_106","doi-asserted-by":"crossref","first-page":"143183","DOI":"10.1016\/j.scitotenv.2020.143183","article-title":"Ozone over Mexico City during the COVID-19 pandemic","volume":"761","author":"Peralta","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_107","doi-asserted-by":"crossref","first-page":"100754","DOI":"10.1016\/j.uclim.2020.100754","article-title":"Impact of lockdown during COVID-19 pandemic on the air quality of North Indian cities","volume":"35","author":"Saxena","year":"2021","journal-title":"Urban Clim."},{"key":"ref_108","doi-asserted-by":"crossref","first-page":"139280","DOI":"10.1016\/j.scitotenv.2020.139280","article-title":"Lockdown for COVID-2019 in Milan: What are the effects on air quality?","volume":"732","author":"Collivignarelli","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_109","doi-asserted-by":"crossref","first-page":"1356","DOI":"10.1016\/j.sjbs.2020.11.065","article-title":"Impact of novel coronavirus disease (COVID-19) lockdown on ambient air quality of Saudi Arabia","volume":"28","author":"Aljahdali","year":"2021","journal-title":"Saudi J. Biol. Sci."},{"key":"ref_110","doi-asserted-by":"crossref","unstructured":"Donzelli, G., Cioni, L., Cancellieri, M., Llopis-Morales, A., and Morales-Su\u00e1rez-Varela, M. (2021). Relations between air quality and COVID-19 lockdown measures in Valencia, Spain. Int. J. Environ. Res. Public Health, 18.","DOI":"10.3390\/ijerph18052296"},{"key":"ref_111","doi-asserted-by":"crossref","first-page":"115927","DOI":"10.1016\/j.envpol.2020.115927","article-title":"Ozone pollution mitigation in guangxi (south China) driven by meteorology and anthropogenic emissions during the COVID-19 lockdown","volume":"272","author":"Fu","year":"2021","journal-title":"Environ. Pollut."},{"key":"ref_112","doi-asserted-by":"crossref","first-page":"1085","DOI":"10.1080\/10962247.2021.1905104","article-title":"Unprecedented reduction in air pollution and corresponding short-term premature mortality associated with COVID-19 lockdown in Delhi, India","volume":"71","author":"Maji","year":"2021","journal-title":"J. Air Waste Manag. Assoc."},{"key":"ref_113","doi-asserted-by":"crossref","unstructured":"Nguyen, T.P.M., Bui, T.H., Nguyen, M.K., Vu, V.T., and Pham, H.L. (2021). Impact of COVID-19 partial lockdown on PM2.5, SO2, NO2, O3, and trace elements in PM2.5 in Hanoi, Vietnam. Environ. Sci. Pollut. Res., 1\u201311.","DOI":"10.1007\/s11356-021-13792-y"},{"key":"ref_114","doi-asserted-by":"crossref","unstructured":"Donzelli, G., Cioni, L., Cancellieri, M., Morales, A.L., and Su\u00e1rez-Varela, M.M. (2020). The effect of the COVID-19 lockdown on air quality in three Italian medium-sized cities. Atmosphere, 11.","DOI":"10.3390\/atmos11101118"},{"key":"ref_115","doi-asserted-by":"crossref","unstructured":"Marinello, S., Lolli, F., and Gamberini, R. (2021). The Impact of the COVID-19 Emergency on local vehicular traffic and its consequences for the environment: The case of the city of Reggio Emilia (Italy). Sustainability, 13.","DOI":"10.3390\/su13010118"},{"key":"ref_116","doi-asserted-by":"crossref","unstructured":"Huang, Y., Zhou, J.L., Yu, Y., Mok, W.-C., Lee, C., and Yam, Y.-S. (2020). Uncertainty in the impact of the COVID-19 pandemic on air quality in Hong Kong, China. Atmosphere, 11.","DOI":"10.3390\/atmos11090914"},{"key":"ref_117","doi-asserted-by":"crossref","first-page":"200381","DOI":"10.4209\/aaqr.2020.07.0381","article-title":"Analysis of air quality during the COVID-19 pandemic lockdown in Naples (Italy)","volume":"21","author":"Sannino","year":"2021","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_118","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1038\/sj.jea.7500338","article-title":"Comparison of spatial interpolation methods for the estimation of air quality data","volume":"14","author":"Wong","year":"2004","journal-title":"J. Expo. Sci. Environ. Epidemiol."},{"key":"ref_119","doi-asserted-by":"crossref","first-page":"129809","DOI":"10.1016\/j.chemosphere.2021.129809","article-title":"Investigating connections between COVID-19 pandemic, air pollution and community interventions for Pakistan employing geoinformation technologies","volume":"272","author":"Mehmood","year":"2021","journal-title":"Chemosphere"},{"key":"ref_120","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.glt.2020.10.002","article-title":"Reduced air pollution during COVID-19: Learnings for sustainability from Indian Cities","volume":"2","author":"Dasgupta","year":"2020","journal-title":"Glob. Transit."},{"key":"ref_121","doi-asserted-by":"crossref","first-page":"1222","DOI":"10.4209\/aaqr.2020.04.0171","article-title":"Social and travel lockdown impact considering coronavirus disease (COVID-19) on air quality in megacities of India: Present benefits, future challenges and way forward","volume":"20","author":"Jain","year":"2020","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_122","doi-asserted-by":"crossref","first-page":"921","DOI":"10.1007\/s11869-020-00863-1","article-title":"Impact of lockdown on air quality in India during COVID-19 pandemic","volume":"13","author":"Singh","year":"2020","journal-title":"Air Qual. Atmos. Health"},{"key":"ref_123","doi-asserted-by":"crossref","first-page":"6913","DOI":"10.1007\/s10668-020-00898-5","article-title":"Significant impacts of COVID-19 lockdown on urban air pollution in Kolkata (India) and amelioration of environmental health","volume":"23","author":"Bera","year":"2021","journal-title":"Environ. Dev. Sustain."},{"key":"ref_124","doi-asserted-by":"crossref","first-page":"200445","DOI":"10.4209\/aaqr.2020.07.0445","article-title":"Effect of lockdown on HCHO and trace gases over India during March 2020","volume":"21","author":"Chauhan","year":"2021","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_125","doi-asserted-by":"crossref","first-page":"100758","DOI":"10.1016\/j.uclim.2020.100758","article-title":"Spatio-temporal concentration of atmospheric particulate matter (PM2.5) during pandemic: A study on most polluted cities of indo-gangetic plain","volume":"35","author":"Das","year":"2021","journal-title":"Urban Clim."},{"key":"ref_126","first-page":"1301","article-title":"Examining the impact of lockdown (due to COVID-19) on ambient aerosols (PM2.5): A study on Indo-Gangetic plain (IGP) cities, India","volume":"35","author":"Das","year":"2021","journal-title":"Stoch. Hydrol. Hydraul."},{"key":"ref_127","doi-asserted-by":"crossref","first-page":"485","DOI":"10.1002\/jeq2.20192","article-title":"Did the COVID-19 lockdown in Delhi and Kolkata improve the ambient air quality of the two cities?","volume":"50","author":"Datta","year":"2021","journal-title":"J. Environ. Qual."}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/4\/1950\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:17:26Z","timestamp":1760134646000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/4\/1950"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,10]]},"references-count":127,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["ijerph19041950"],"URL":"https:\/\/doi.org\/10.3390\/ijerph19041950","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,10]]}}}