Impact of Lockdown on Air Pollutants during COVID-19 at Patna, India

Many countries shut their borders, imposed nationwide lockdown, and restricted several anthropogenic activities to arrest the spread of COVID-19. In the present study, the concentration of several air pollutants (PM10, PM2.5, NO2, NH3, SO2, CO and O3) during different phases of lockdown from monitoring stations of Patna was analyzed to assess the effect of lockdown restriction on air quality. Reduction in PM2.5, NH3, NO2, PM10 and CO concentration was observed by 59.79%, 58.2%, 49.49%, 39.57% and 24.04%, respectively during the lockdown period. National Air Quality Index (NAQI) value in the year 2020 had been observed to lower by 57.88% compared to the year 2019, during the same period. A more significant fall in the concentration of air pollutants was observed during the early phase of post-lockdown compared to the late stages of postlockdown. The study reflects the significance of restriction on anthropogenic activities in improving air quality and provides clues for future action plans for improving air quality.