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Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic.
Environ Pollut. 2021 Sep 15; 285:117664.EP

Abstract

The impacts of COVID-19 lockdown restrictions have provided a valuable global experiment into the extent of improvements in air quality possible with reductions in vehicle movements. Mexico City, London and Delhi all share the problem of air quality failing WHO guideline limits, each with unique situations and influencing factors. We determine, discuss and compare the air quality changes across these cities during the COVID-19, to understand how the findings may support future improvements in their air quality and associated health of citizens. We analysed ground-level PM10, PM2.5, NO2, O3 and CO changes in each city for the period 1st January to August 31, 2020 under different phases of lockdown, with respect to daily average concentrations over the same period for 2017 to 2019. We found major reductions in PM10, PM2.5, NO2 and CO across the three cities for the lockdown phases and increases in O3 in London and Mexico City but not Delhi. The differences were due to the O3 production criteria across the cities, for Delhi production depends on the VOC-limited photochemical regime. Levels of reductions were commensurate with the degree of lockdown. In Mexico City, the greatest reduction in measured concentration was in CO in the initial lockdown phase (40%), in London the greatest decrease was for NO2 in the later part of the lockdown (49%), and in Delhi the greatest decrease was in PM10, and PM2.5 in the initial lockdown phase (61% and 50%, respectively). Reduction in pollutant concentrations agreed with reductions in vehicle movements. In the initial lockdown phase vehicle movements reduced by up to 59% in Mexico City and 63% in London. The cities demonstrated a range of air quality changes in their differing geographical areas and land use types. Local meteorology and pollution events, such as forest fires, also impacted the results.

Authors+Show Affiliations

Centro de Ciencias de la Atmósfera, National Autonomous University of Mexico (UNAM), Mexico. Electronic address: evega@atmosfera.unam.mx.Geography and Environmental Sciences Department, Northumbria University, UK.Geography and Environmental Sciences Department, Northumbria University, UK.Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, UNAM, Mexico.Secretaría de Medio Ambiente, Dirección de Monitoreo de Calidad del Aire, Subdirección de Análisis y Modelación, Mexico.Secretaría de Medio Ambiente, Dirección de Monitoreo de Calidad del Aire, Subdirección de Análisis y Modelación, Mexico.Secretaría de Medio Ambiente, Dirección de Monitoreo de Calidad del Aire, Subdirección de Análisis y Modelación, Mexico.Secretaría de Medio Ambiente, Dirección de Monitoreo de Calidad del Aire, Subdirección de Análisis y Modelación, Mexico.Geography and Environmental Sciences Department, Northumbria University, UK.Geography and Environmental Sciences Department, Northumbria University, UK.Instituto Mexicano del Seguro Social (IMSS), Mexico.Instituto Mexicano del Seguro Social (IMSS), Mexico.Mathematics, Physics and Electrical Engineering, Northumbria University, UK.Population Health Sciences Institute, Newcastle University, UK.Population Health Sciences Institute, Newcastle University, UK.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

34380230

Citation

Vega, E, et al. "Changes in Air Quality in Mexico City, London and Delhi in Response to Various Stages and Levels of Lockdowns and Easing of Restrictions During COVID-19 Pandemic." Environmental Pollution (Barking, Essex : 1987), vol. 285, 2021, p. 117664.
Vega E, Namdeo A, Bramwell L, et al. Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic. Environ Pollut. 2021;285:117664.
Vega, E., Namdeo, A., Bramwell, L., Miquelajauregui, Y., Resendiz-Martinez, C. G., Jaimes-Palomera, M., Luna-Falfan, F., Terrazas-Ahumada, A., Maji, K. J., Entwistle, J., Enríquez, J. C. N., Mejia, J. M., Portas, A., Hayes, L., & McNally, R. (2021). Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic. Environmental Pollution (Barking, Essex : 1987), 285, 117664. https://doi.org/10.1016/j.envpol.2021.117664
Vega E, et al. Changes in Air Quality in Mexico City, London and Delhi in Response to Various Stages and Levels of Lockdowns and Easing of Restrictions During COVID-19 Pandemic. Environ Pollut. 2021 Sep 15;285:117664. PubMed PMID: 34380230.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic. AU - Vega,E, AU - Namdeo,A, AU - Bramwell,L, AU - Miquelajauregui,Y, AU - Resendiz-Martinez,C G, AU - Jaimes-Palomera,M, AU - Luna-Falfan,F, AU - Terrazas-Ahumada,A, AU - Maji,K J, AU - Entwistle,J, AU - Enríquez,J C Núñez, AU - Mejia,J M, AU - Portas,A, AU - Hayes,L, AU - McNally,R, Y1 - 2021/06/30/ PY - 2021/02/23/received PY - 2021/06/23/revised PY - 2021/06/24/accepted PY - 2021/8/12/entrez PY - 2021/8/13/pubmed PY - 2021/8/14/medline KW - Air pollution KW - Covid-19 restrictions KW - Delhi KW - Lockdown KW - London KW - Mexico City KW - Particulate matter SP - 117664 EP - 117664 JF - Environmental pollution (Barking, Essex : 1987) JO - Environ Pollut VL - 285 N2 - The impacts of COVID-19 lockdown restrictions have provided a valuable global experiment into the extent of improvements in air quality possible with reductions in vehicle movements. Mexico City, London and Delhi all share the problem of air quality failing WHO guideline limits, each with unique situations and influencing factors. We determine, discuss and compare the air quality changes across these cities during the COVID-19, to understand how the findings may support future improvements in their air quality and associated health of citizens. We analysed ground-level PM10, PM2.5, NO2, O3 and CO changes in each city for the period 1st January to August 31, 2020 under different phases of lockdown, with respect to daily average concentrations over the same period for 2017 to 2019. We found major reductions in PM10, PM2.5, NO2 and CO across the three cities for the lockdown phases and increases in O3 in London and Mexico City but not Delhi. The differences were due to the O3 production criteria across the cities, for Delhi production depends on the VOC-limited photochemical regime. Levels of reductions were commensurate with the degree of lockdown. In Mexico City, the greatest reduction in measured concentration was in CO in the initial lockdown phase (40%), in London the greatest decrease was for NO2 in the later part of the lockdown (49%), and in Delhi the greatest decrease was in PM10, and PM2.5 in the initial lockdown phase (61% and 50%, respectively). Reduction in pollutant concentrations agreed with reductions in vehicle movements. In the initial lockdown phase vehicle movements reduced by up to 59% in Mexico City and 63% in London. The cities demonstrated a range of air quality changes in their differing geographical areas and land use types. Local meteorology and pollution events, such as forest fires, also impacted the results. SN - 1873-6424 UR - https://www.unboundmedicine.com/medline/citation/34380230/Changes_in_air_quality_in_Mexico_City_London_and_Delhi_in_response_to_various_stages_and_levels_of_lockdowns_and_easing_of_restrictions_during_COVID_19_pandemic_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0269-7491(21)01246-X DB - PRIME DP - Unbound Medicine ER -