Global assessment of tropospheric and ground air pollutants and its correlation with COVID-19

The declaration of COVID-19 pandemic by the WHO initiated a series of lockdowns globally that varied in stringency and duration; however, the spatiotemporal effects of these lockdowns on air quality remain understudied. This study evaluates the global impact of lockdowns on air pollutants using tropospheric and ground-level indicators over a five-month period. Moreover, the relationship between air pollution and COVID-19 cases and mortalities was examined. Changes in the global tropospheric (NO(2), aerosols, and O(3)) and ground-level (PM(2.5), PM(10), NO(2), and O(3)) pollutants were observed, and the maximum air quality improvement was observed immediately after lockdown. Except for a few countries, a decline in air pollutants correlated with a reduction in Land Surface Temperature (LST). Notably, regions with higher tropospheric NO(2) and aerosol concentrations were also COVID-19 hotspots. Our analysis showed moderate positive correlation for NO(2) with COVID-19 cases (R(2) = 0.33; r = 0.57, P = 0.006) and mortalities (R(2) = 0.40; r = 0.63, P = 0.015), while O(3) showed a weak-moderate positive correlation with COVID-19 cases (R(2) = 0.22; r = 0.47, P = 0.003) and mortalities (R(2) = 0.12; r = 0.35, P = 0.012). However, PM(2.5), and PM(10) showed no significant correlation with either COVID-19 cases or mortality. This study reveals that humans living under adverse air pollution conditions are at higher risk of COVID-19 infection and mortality.