Impact of COVID-19 on PM2.5 Pollution in Fastest-Growing Megacity Dhaka, Bangladesh.

Objective: The purpose of the research was to investigate and identify the impact of COVID-19 lockdown on fine particulate matter (PM_2.5) pollution in Dhaka, Bangladesh by using ground-based observation data. Methods: The research assessed air quality during the COVID-19 pandemic for PM_2.5 from January 1, 2017 to August 1, 2020. The research considered pollution in pre-COVID-19 (January 1 to March 23), during COVID-19 (March 24 to May 30), and post-COVID-19 (May 31 to August 1) lockdown periods with current (2020) and historical (2017-2019) data. Results: PM_2.5 pollution followed a similar yearly trend in year 2017-2020. The average concentration for PM_2.5 was found 87.47 μg/m3 in the study period. Significant PM_2.5 declines were observed in the current COVID-19 lockdown period compared with historical data: 11.31% reduction with an absolute decrease of 7.15 μg/m3. Conclusions: The findings of the research provide an overview of how the COVID-19 pandemic affects air pollution. The results will provide initial evidence regarding human behavioral changes and emission controls. This research will also suggest avenues for further study to link the findings with health outcomes. [ABSTRACT FROM AUTHOR]