Special Issue on COVID-19 Aerosol Drivers, Impacts and Mitigation (XII)

Mehdi Amouei Torkmahalleh This email address is being protected from spambots. You need JavaScript enabled to view it.1, Zarina Akhmetvaliyeva1, Ali Darvishi Omran2, Faezeh Darvish Omran3, Mohadeseh Kazemitabar3, Mahtab Naseri3, Motahareh Naseri1, Hamed Sharifi3, Milad Malekipirbazari4Enoch Kwasi Adotey1, Soudabeh Gorjinezhad1,5, Neda Eghtesadi1, Sergei Sabanov6, Andrés Alastuey7, María de Fátima Andrade8, Giorgio Buonanno5,9, Samara Carbone10, Diego Ernesto Cárdenas-Fuentes11, Flemming R. Cassee12,13, Qili Dai14, Andrés Henríquez15, Philip K. Hopke16, Petri Keronen17, Haider Abbas Khwaja18,19, Jong Kim20, Markku Kulmala17, Prashant Kumar21, Jonilda Kushta22, Joel Kuula23, Jordi Massagué7, Tamsin Mitchell24, Dennis Mooibroek12, Lidia Morawska9, Jarkko V. Niemi25, Soulemane Halif Ngagine26, Michael Norman27, Beatríz Oyama8, Pedro Oyola15, Fatma Öztürk28, Tuukka Petäjä17, Xavier Querol7, Yousef Rashidi29, Felipe Reyes15, Matthew Ross-Jones30, Tunga Salthammer31, Chrysanthos Savvides32, Luca Stabile5, Karin Sjöberg33, Karin Söderlund31, Ramya Sunder Raman34,35, Hilkka Timonen23, Masakazu Umezawa36, Mar Viana7, Shanju Xie37

1 Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Nur-Sultan, 010000, Kazakhstan
2 School of Civil and Environmental Engineering, Iran University of Science and Technology, Tehran, Iran
3 Department of Ambient Air Quality, Rizgard Payesh Asman LLP., Tehran, 1484667536, Iran
4 Department of Industrial Engineering, Bilkent University, Bilkent, Ankara, 06800, Turkey
5 Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, via Di Biasio 43, Cassino 03043, Italy
6 Department of mining, School of Mining and Geosciences, Nazarbayev University, Nur-Sultan, Kazakhstan
7 Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Spanish Research Council - CSIC, C/ Jordi Girona 18, 08034 Barcelona, Spain
8 Institute of Astronomy, Geophysics and Atmospheric Science, University of São Paulo, Brazil
9 International Laboratory for Air Quality and Health, Science and Engineering Faculty, Queensland University of Science and Technology, 2 George Street, Brisbane, Queensland 4001, Australia
10 Federal University of Uberlandia, Agrarian Sciences Institute, Uberlandia, Brazil
11 School of Engineering and Sciences, Tecnológico de Monterrey, Monterrey, Mexico
12 National Institute for Public Health and the Environment (RIVM), PO box 1, 3720 BA Bilthoven, The Netherlands
13 Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands
14 State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
15 Centro Mario Molina Chile, Antonio Bellet 292/602, Santiago, Chile
16 Department of Public Health Sciences, University of Rochester Medical Center, Rochester, NY, 14642, USA
17 Institute for Atmospheric and Earth System Research (INAR) / Physics, PO. Box 64, 00014, University of Helsinki, Finland
18 Wadsworth Center, New York State Department of Health, Albany, NY, USA
19 Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, New York, USA
20 Department of Civil and Environmental Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Nur-Sultan, 010000, Kazakhstan
21 Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, Surrey, UK
22 The Cyprus Institute, Climate and Atmosphere Research Center (CARE-C), 2121, Nicosia, Cyprus
23 Atmospheric Composition Research, Finnish Meteorological Institute, P.O.Box 503, 00101 Helsinki, Finland
24 Environmental Science Department, Greater Wellington Regional Council, Manners St, Wellington 6142, New Zealand
25 Helsinki Region Environmental Services Authority (HSY), PO Box 100, FI-00066, Helsinki, Finland
26 Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
27 Environment and health administration, City of Stockholm, S-104 20 Stockholm, Sweden
28 Environmental Engineering Department, Faculty of Engineering, Bolu Abant Izzet Baysal University (BAIBU), Golkoy Campus, 14030, Bolu, Turkey
29 Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran
30 Swedish Environmental Protection Agency, Stockholm, Sweden
31 Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, 38108 Braunschweig, Germany
32 Air Quality Section, Department of Labour Inspection, Ministry of Labour Welfare and Social Insurance of the Republic of Cyprus, Nicosia, Cyprus
33 Swedish Environmental Research Institute, Environmental Intelligence, Gothenburg, Sweden
34 Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
35 Center for Research on Environment and Sustainable Technologies Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal - 462 066, Madhya Pradesh, India
36 Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
37 Research & Evaluation Unit (RIMU), Auckland Council, Auckland, New Zealand

Received: September 19, 2020
Revised: December 15, 2020
Accepted: January 28, 2021

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.200567  

Cite this article:

Amouei Torkmahalleh, M., Akhmetvaliyeva, Z., Omran, A.D., Darvish Omran, F., Kazemitabar, M., Naseri, M., Naseri, M., Sharifi, H., Malekipirbazari, M., Kwasi Adotey, E., Gorjinezhad, S., Eghtesadi, N., Sabanov, S., Alastuey, A., de Fátima Andrade, M., Buonanno, G., Carbone, S., Cárdenas-Fuentes, D.E., Cassee, F.R., Dai, Q., Henríquez, A., Hopke, P.K., Keronen, P., Khwaja, H.A., Kim, J., Kulmala, M., Kumar, P., Kushta, J., Kuula, J., Massagué, J., Mitchell, T., Mooibroek, D., Morawska, L., Niemi, J.V., Ngagine, S.H., Norman, M., Oyama, B., Oyola, P., Öztürk, F., Petäjä, T., Querol, X., Rashidi, Y., Reyes, F., Ross-Jones, M., Salthammer, T., Savvides, C., Stabile, L., Sjöberg, K., Söderlund, K., Sunder Raman, R., Timonen, H., Umezawa, M., Viana, M., Xie, S. (2021). Global Air Quality and COVID-19 Pandemic: Do We Breathe Cleaner Air? Aerosol Air Qual. Res. 21, 200567. https://doi.org/10.4209/aaqr.200567



  • Globally, NO2 and PM2.5 declined while O3 increased during the COVID-19 lockdowns.
  • NO2 was the pollutant mostly affected by the COVID-19 pandemic.
  • Most of the studied cities were VOC limited.
  • Increased O3 concentrations during the lockdown has facilitated SOA formation.


The global spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has challenged most countries worldwide. It was quickly recognized that reduced activities (lockdowns) during the Coronavirus Disease of 2019 (COVID-19) pandemic produced major changes in air quality. Our objective was to assess the impacts of COVID-19 lockdowns on ground-level PM2.5, NO2, and O3 concentrations on a global scale. We obtained data from 34 countries, 141 cities, and 458 air monitoring stations on 5 continents (few data from Africa). On a global average basis, a 34.0% reduction in NO2 concentration and a 15.0% reduction in PM2.5 were estimated during the strict lockdown period (until April 30, 2020). Global average O3 concentration increased by 86.0% during this same period. Individual country and continent-wise comparisons have been made between lockdown and business-as-usual periods. Universally, NO2 was the pollutant most affected by the COVID-19 pandemic. These effects were likely because its emissions were from sources that were typically restricted (i.e., surface traffic and non-essential industries) by the lockdowns and its short lifetime in the atmosphere. Our results indicate that lockdown measures and resulting reduced emissions reduced exposure to most harmful pollutants and could provide global-scale health benefits. However, the increased O3 may have substantially reduced those benefits and more detailed health assessments are required to accurately quantify the health gains. At the same, these restrictions were obtained at substantial economic costs and with other health issues (depression, suicide, spousal abuse, drug overdoses, etc.). Thus, any similar reductions in air pollution would need to be obtained without these extensive economic and other consequences produced by the imposed activity reductions.

Keywords: SARS-CoV-2, Global air quality, PM2.5, NO2, O3, COVID-19 pandemic

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