Evaluating aerosols concentration and air quality of Indian urban agglomerations over nationwide and regional lockdown

Abstract

In the past two years, numerous researches are done on how lockdowns across the world affected air quality; however, less research is done on how geolocation, geo-climate, anthropogenic activities had such impacts. National and regional shutdowns at various lockdown phases are crucial for evaluating such impacts. The goal of the current study was to examine the effects of geographic location, geo-climate, and human activity on Particulate Matter (PM10 and PM2.5) concentration and air quality about COVID-19-induced lockdowns of Mumbai and Delhi, two economically significant megacities in India with contrasting climatic conditions. Based on the incidents where restricted economic activity led to lockdowns, the importance of meteorological and economic activity in controlling air quality was evaluated. To understand spatial distribution, variability, trend, consistency analysis and National Air Quality Index (NAQI) of PM10 and PM2.5 data were collected from the Central Pollution Control Board (CPCB) monitoring system. To account for variation in various urban morphological units and gauge their responses, dispersion analysis was used. Kernel Density Estimation (KDE) plots were used to study how PM affected NAQI. From the analysis, it was clear that (1) nationwide lockdown was more fruitful in Delhi while regional lockdown in Mumbai since air quality improvement rate was substantially high in Mumbai in regional lockdown, 2021, (2) Mumbai city maritime location and long open sea coast help to reduce pollution levels while Delhi's continental location is crucial for being higher pollution levels, (3) control of meteorological factors was not found very significant, however, it was found relatively greater in Delhi, (4) air quality was found to be extremely poor in industrial and commercial areas during unlocking periods, but sensitively greater improvement was also found during lockdown periods, indicating crucial anthropogenic impact on air quality, and (5) rate of air quality improvement was highly correlated with different economic contributors. As a result, this study came to the conclusion that conditions with controlled demand can improve the air quality.