Effect on Ambient Air Quality in Nagpur due to lockdown to contain the spread of COVID-19 pandemic in the year 2020: a case study

The present paper deals with the studies on the change in concentration of three standard pollutants namely, respiratory suspended particulate matter (RSPM or PM(10)), Sulphur dioxide (SO(2)) and Nitrogen dioxide (NO(2)) because of lockdown in India to prevent the spread of COVID-19 pandemic in 2020. The monthly average concentrations of the above pollutants observed at four monitoring stations in and around Nagpur city during January to December 2020 were analyzed and compared. Due to COVID-19 pandemic, there was a complete lockdown from 25th March to 31st May 2020 and phased reopening of areas outside containment zones from June 1st onwards. It is found that the average concentration of all the three pollutants at all four stations was reduced by about 50 % to 75 % due to lockdown. During lockdown, the minimum concentration of PM(10), SO(2) and NO(2) amongst all stations were found to be 40, 5 and 11 µg/m(3,) respectively, whereas the maximum concentrations were found to be 159, 20, and 50 µg/m(3,) respectively. The concentrations during lockdown were below the standards prescribed by CPCB, which were found to increase due to reopening. The Air quality index (AQI) at all four stations during lockdown was less than 50 (i.e. SATISFACTORY), whereas it increased above 100 (i.e. MODERATE) after reopening. As a result, the annual average concentration of pollutants was reduced in 2020 compared to previous years.