ArticleSustainable cities and society2021
Air quality during three covid-19 lockdown phases: AQI, PM2.5 and NO2 assessment in cities with more than 1 million inhabitants.
Article in Sustainable cities and society, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 31 papers.
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31 citing papers in PubMed.
- Human mobility under disasters: a systematic review and framework for equitable and resilient mobility governance.npj natural hazards · 2025Article
- Article
- Prediction of atmospheric PMScientific reports · 2024Article
- Indirect Effects of PMAnnals of global health · 2024Article
- Changes in air pollution, land surface temperature, and urban heat islands during the COVID-19 lockdown in three Chinese urban agglomerations.The Science of the total environment · 2023Article
- Impacts of COVID-19's restriction measures on personal exposure to VOCs and aldehydes in Taipei City.The Science of the total environment · 2023Article
- Impact of COVID-19 restrictions on hourly levels of PM10, PM2.5 and black carbon at an industrial suburban site in northern Spain.Atmospheric environment (Oxford, England : 1994) · 2023Article
- How does COVID-19 lockdown affect air quality: Evidence from Lanzhou, a large city in Northwest China.Urban climate · 2023Article
- Air pollution and mobility patterns in two Ugandan cities during COVID-19 mobility restrictions suggest the validity of air quality data as a measure for human mobility.Environmental science and pollution research international · 2023Article
- Changes in NO2 and O3 levels due to the pandemic lockdown in the industrial cities of Tehran and Arak, Iran using Sentinel 5P images, Google Earth Engine (GEE) and statistical analysis.Stochastic environmental research and risk assessment : research journal · 2023Article
- The lock-down effects of COVID-19 on the air pollution indices in Iran and its neighbors.Modeling earth systems and environment · 2023Article
- Changes in air pollution due to COVID-19 lockdowns in 2020: Limited effect on NOJournal of global health · 2022Article
- Investigation of pre and post environmental impact of the lockdown (COVID-19) on the water quality of the Capibaribe and Tejipió rivers, Recife metropolitan region, Brazil.Journal of South American earth sciences · 2022Article
- Unraveling the dynamic impacts of COVID-19 on metro ridership: An empirical analysis of Beijing and Shanghai, China.Transport policy · 2022Article
- Geographies of infections: built environment and COVID-19 pandemic in metropolitan Melbourne.Sustainable cities and society · 2022Article
- Evaluation of NOx emissions before, during, and after the COVID-19 lockdowns in China: A comparison of meteorological normalization methods.Atmospheric environment (Oxford, England : 1994) · 2022Article
- Temporal characteristics and spatial heterogeneity of air quality changes due to the COVID-19 lockdown in China.Resources, conservation, and recycling · 2022Article
- ANN-Based traffic volume prediction models in response to COVID-19 imposed measures.Sustainable cities and society · 2022Article
- Empirical evidence shows that air quality changes during COVID-19 pandemic lockdown in Jakarta, Indonesia are due to seasonal variation, not restricted movements.Environmental research · 2022Article
- COVID-19 and transportation of India: influence on infection risk and greenhouse gas emissions.Environment, development and sustainability · 2022Article
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5 authors.
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Abstract
Implemented quarantine due to the ongoing novel coronavirus (agent of COVID-19) has an immense impact on human mobility and economic activities as well as on air quality. Since then, and due to the drastic reduction in pollution levels in cities across the world, a large discussion has been magnetized regarding if the lockdown is an adequate alternative counter-measure for enhancing air quality. This paper aimed at studying the Air Quality Index (AQI), PM2.5, and tropospheric NO2 levels in three lockdown phases (before, during, and after) among 21 cities around the world. Simple before/after comparison approach was carried out to capture the declining trend in air pollution levels caused by the lockdown restrictions. The results showed that the frequency distribution for NO2 is more variable than that for PM2.5, and the distribution is flatter from 2020 to the baseline 2018-2019 period. Besides, AQI, in most of the cities, has varied from high to mild pollution during the lockdown and was moderate before. Although during the lockdown, a reduction of 3 to 58% of daily NO2 concentrations was observed across the cities, an increase was detected in three cities including Abidjan (1%), Conakry (3%), and Chengdu (10%). Despite this mixed trend, the NO2 time series clearly showed the effect of the unlocking phase where the NO2 levels increased in almost all cities. Similarly, PM2.5 concentrations have increased in the post-lockdown period, with 50% of the cities reporting significant positive differences between the lock and the unlock phase. Then, the levels of PM2.5 were higher at the pre-lockdown phase than at any other time exhibiting a "U" shape. In addition, during Ramadan, it was noted that altered patterns of daily activities in some Islamic cities have a significant negative impact on air quality.
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