Effects of COVID-19 lockdown on ambient air pollution in Madhya Pradesh, India.

The paper aims to quantify the changes in the pollutants level in the ambient air of Madhya Pradesh during COVID-19 induced 21 days lockdown. The data of 16 continuous ambient air quality monitoring stations (CAAQMS) for six pollutants, namely PM_2.5, PM₁₀, SO₂, NO_x, CO, and Ozone for pre-lockdown (1–21 March 2020) and lockdown (25 March-14 April 2020) period was compiled and appropriate statistical analysis was done. The result showed a reduction of 13%, 20%, 37%, 39% and 25% in the ambient air level of PM_2.5, PM₁₀, SO₂, NO_x and CO, respectively, during the lockdown. No such declining trend was observed in the ambient air ozone level. Ambient air ozone level changed between −22 and +30% compared to pre-lockdown concentrations. The mean ambient air ozone concentration was reduced at the residential/commercial stations (−5%), but was increased at the industrial stations (+19%) concentration. [ABSTRACT FROM AUTHOR]