Effect of SARS-CoV-2 pandemic induced lockdown on the aerosol loading over the coastal state, Goa

Abstract

The SARS-CoV-2 pandemic resulted in India imposing a nationwide lockdown on 22 March 2020, bringing all human activities to a complete halt. The current study focuses on the effect of lockdown on the abundance of atmospheric aerosols over Goa. The study focused on pre-lockdown, lockdown and period corresponding to lockdown in 2019. The AOD spectra depicted a decrease in the anthropogenically derived fine mode aerosols during the lockdown compared to the pre-lockdown period. Mean AOD sub(500) for pre-lockdown and lockdown periods were 0.43 plus or minus 0.19 and 0.53 plus or minus 0.11 respectively. The higher AOD sub(500) during lockdown was due to an increase in naturally derived coarse mode aerosols, which is further confirmed with the lower Angstrom exponent values (1.04 plus or minus 0.11). The mean black carbon mass concentration for the respective periods were 1990.45 plus or minus 470.87 ng m sup(-3) and 1109.71 plus or minus 218.33 ng m sup(-3), and the mean atmospheric forcing during the respective periods were 25.13 plus or minus 5.72 W m sup(-2), 27.31 plus or minus 3.71 W m sup(-2) and 30.81 plus or minus 5.59 W m sup(-2) respectively.