Large Variation in Concentrations of Ultrafine (PM.,) and Coarse (PM10) Mode Particulate Matter during Lockdown and Unlock Phases of Covid-19

ABSTRACT

Due to the strict enforcement of lockdown, the air quality index improved drastically in the cities across the globe within a few days of lockdown globally. The present study was conducted in Jaipur city to evaluate the effect of lockdown phases on the concentrations of PM10, PM1 # NO2, SO2, CO and O3. Among the selected pollutants PM1 (-61.15%) and PM10 (-40.50%) witnessed the maximum reduction in the lockdown phase 1. Among others, gaseous pollutants also showed a declining trend, as N02(-69.61 %) witnessed maximum reduction followed by CO (-25%) and SO2(-13.74%). In contrast to this, the O3(+24.26%) showed the opposite trend. The decreasing trend of pollutant concentrations continued upto the 2nd phase of lockdown, after which conditional relaxations in restrictions led to an increase in pollutants. In comparison to last year (that is 2019) during the same period, the concentration of atmospheric pollutants in 2020 was found to be very low. Ultrafine particulate matter showed a decreasing trend throughout the study whereas coarse mode particles shows a decreasing trend till the 3rd phase of lockdown and increased later on. Whereas, most of the gaseous pollutants show a decreasing trend in almost all phases except O,showing a reverse trend. © 2022 Scientific Publishers. All rights reserved.