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. 2021 May 17;193(6):343.
doi: 10.1007/s10661-021-09120-z.

Effect of COVID-19 pandemic-induced lockdown (general holiday) on air quality of Dhaka City

Md Saiful Islam  1 , Tahmid Anam Chowdhury  2   3
Affiliations

Effect of COVID-19 pandemic-induced lockdown (general holiday) on air quality of Dhaka City

Md Saiful Islam et al. Environ Monit Assess. .

Abstract

A worldwide pandemic of COVID-19 has forced the Government of Bangladesh to implement a lockdown during April-May 2020 by restricting people's movement; shutdown of industries and motor vehicles; and closing markets, public places, and schools to contain the virus. This type of strict measures caused an outcome, the reduction of urban air pollution, around the world. The present study aims to investigate the reduction of the concentration of pollutants in the air of Dhaka City and the reduction of the Air Quality Index (AQI). Necessary time-series data of the concentration of PM2.5, NO2, SO2, and CO have been collected from the archive of the Air Quality Monitoring Station of the US Embassy in Dhaka and Sentinel-5P. The time-series data have been analyzed by descriptive statistics, and AQI was calculated following an appropriate formula suggested by the Environmental Protection Agency (EPA) based on the criteria pollutants. The study found that the concentrations of PM2.5, NO2, SO2, and CO during April-May 2020 have been reduced by 26, 30, 07, and 07%, respectively, compared with the preceding year's concentrations. Moreover, the AQI has also been reduced by about 35% on average during the lockdown period than the same times of the previous year. However, the magnitude of pollution reduction in Dhaka is lower than in other cities and countries globally, including Delhi, Sao Paulo, Wuhan, Spain, Italy, the USA. The main reasons may include, among others, the poor implementation of lockdown (especially in the first week of April and the second fortnight of May), pre-existing pollution, transboundary pollution, incineration of solid waste, etc. This study will help policymakers figure out how to regulate pollution sources and improve the air quality of Dhaka.

Keywords: Air Quality Index; Air quality; COVID-19 pandemic; Dhaka megacity; Lockdown.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Map of Dhaka showing the location of air quality monitoring station
Fig. 2
Fig. 2
Time-series plots of NO2, SO2, and CO during April–May 2019 and 2020
Fig. 3
Fig. 3
Atmospheric concentration of NO2, SO2, and CO over Dhaka in April 2019 and 2020
Fig. 4
Fig. 4
The percentage of AQI classes during lockdown period and the same times of previous years
See this image and copyright information in PMC

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