Significant Changes in Urban Air Quality during Covid-19 Pandemic Lockdown in Rohtak City, India

Abstract

The global spread of Covid-19 brought a dramatic decrease in vehicular activities, industrial activities and tourism for a limited period of time during the lockdown phase (Year 2020). The variations in ambient air quality were studied in Maharshi Dayanand University, Rohtak city (Haryana state, India) during the lockdown period and pollutants data were gathered from Haryana State Pollution Control Board (HSPCB). The study was conducted for 186 days in three periods; first pre-lockdown, second during the lockdown and third during post-lockdown phase (62 days each). The results showed a significantly decreased the levels of air pollutants through the lockdown season in comparison to pre and post-lockdown concentrations of air pollutants. Mean PM2.5 concentration was found to be higher than their standard limit for the episode of pre and post-lockdown and the mean value of PM2.5 was 2.3 and 2.8 times higher in pre and post-lockdown compared to during the lockdown period. The average air quality index (AQI) during lockdown has shown a 64.1% decrease as compared to pre-lockdown data and a 69.3% reduction from post-lockdown period. Based on one way Analysis of variance (ANOVA) results show ozone accepts the null hypothesis that lockdown had no effect on the atmospheric pollutant concentration due to the increasing pattern of ozone concentration because of a decrease in the concentration of NOx, which breakdown ozone.