Geospatial analysis of COVID-19 lockdown effects on air quality in the South and Southeast Asian region

21, November 2020 | Bangladesh

Authors:

Abstract

The COVID-19 pandemic, induced by the novel Coronavirus worldwide outbreak, is causing countries to intro- duce different types of lockdown measures to curb the contagion. The implementation of strict lockdown policies has had unprecedented impacts on air quality globally. This study is an attempt to assess the effects of COVID-19 induced lockdown measures on air quality in both regional, country, and city scales in the South and Southeast Asian region using open-source satellite-based data and software frameworks. We performed a systematic re- view of the national lockdown measures of 19 countries of the study area based on publicly available materials. We considered two temporal settings over a period of 66 days to assess and compare the effects of lockdown measures on air quality levels between standard business as usual and current situation COVID-19 lockdown. Re- sults showed that compared to the same period of 2019, atmospheric NO2, SO2, PM2.5, and CO levels decreased by an average of 24.16%, 19.51%, 20.25%, and 6.88%, respectively during the lockdown, while O3 increased by a max- imum of 4.52%. Among the 19 studied cities, Dhaka, Kathmandu, Jakarta, and Hanoi experienced the highest re- duction of NO2 (40%–47%) during the lockdown period compared to the corresponding period of 2019. The methodological framework applied in this study can be used and extended to future research in the similar do- main such as understanding long-term effects of COVID-19 mitigation measures on the atmospheric pollution at continental-scale or assessing the effects of the domestic emissions during the stay-at-home; a standard and ef- fective COVID-19 lockdown measure applied in most of the countries.