Effects of Nationwide COVID-19 Lockdown on Fossil Fuel and Biomass Burning Emissions in India

Abstract

The nationwide lockdown imposed in India in various phases to contain the spread of the COVID-19 pandemic led to a substantial reduction in anthropogenic emissions. This study conducts a thorough examination of equivalent black carbon (EBC) aerosol mass concentrations, utilizing a multi-wavelength aethalometer installed at eight stations (Bhuj, Guwahati, Jodhpur, Nagpur, New Delhi, Pune, Ranichauri, and Thiruvananthapuram) under the India Meteorological Department (IMD) EBC observation network from 2016 to 2020. The investigation aimed to assess variations in EBC, specifically its quantitative contributions from biomass burning (EBC_BB) and fossil fuels (EBC_FF), during the lockdown (LD) and unlock (UL) periods in 2020 compared to the 2016–2019 period. Results indicated a 47% reduction in EBC mass concentration during the lockdown period and a 24% reduction during the unlock period compared to the normal period. EBC_FF and EBC_BB concentrations experienced a 53% and 17% decrease, respectively, during the lockdown period, attributable to significant reductions in fossil fuel and biomass burning emissions. Throughout the lockdown period, the average contributions of EBC_FF and EBC_BB to total EBC mass concentrations were 70% and 30%, respectively, whereas during the normal period, these values were 82% and 18%. The observed reductions in equivalent black carbon concentrations aligned with decreased emissions from both transportation and industrial activities. The restrictions during the COVID-19 pandemic lockdown led to a decrease in diffusion radiation and aerosol optical depth (AOD). These findings provide comprehensive insights into the sources of EBC and emission control strategies during the unprecedented COVID-19-induced lockdown. The study contributes valuable information for shaping future emission control strategies aimed at improving air quality and addressing climate concerns.