Global Air Quality Change Detection During Covid-19 Pandemic Using Space-Borne Remote Sensing and Global Atmospheric Reanalysis

In contrast to existing research that used ground-based observations, in this research we used space-borne observations to study global air quality change during COVID-19 pandemic in 20 countries. It is observed that during lockdown, PM2.5 has reduced in the most of the countries by 56% in 2020 compared to the previous year, whereas, Ghana and Russia show an increasing pattern. It is observed that NO2 has dropped in most of the countries by 3% to 31%, whereas UK and South Africa exhibit an increasing trend. Although spatial variability, low spatial resolution, and mixed pixel impurity may obscure the observation, but the study suggests a space-borne approach can be useful for investigating change in air quality to provide a general insight during COVID-19 pandemic. Our space-borne observations show an improvement in air quality by considerable drop in contaminants in the air in most of the countries except Russia and Ghana during COVID lockdown.