Variation of black carbon and particulate matter in Bhubaneswar during the pre-monsoon: possible impact of meteorology and COVID-19 lockdown

Abstract

To combat the present COVID-19 pandemic, a countrywide lockdown (LD) was imposed in India from 25 March until 31 May 2020. This unique scenario brought a decline in various anthropogenic activities leading to a considerable decrease in the concentration of several atmospheric pollutants. In this scenario, CSIR-IMMT Bhubaneswar carried out black carbon (BC), PM10 and PM2.5 analysis through optical and gravimetric measurements, respectively, during March-May 2020 followed by a comparison with previous years (2017-2018) of observation. There was a reduction of similar to 33% in average overall BC concentration along with a significant drop in PM10 (33%) (P < 0.05) and PM2.5 (similar to 38%) (P < 0.05) during the entire LD period as compared to 2017-2018. During LD, contribution from biomass burning was enhanced by almost 3 times as compared to 2017-2018. However, the simultaneous meteorological variation during the LD period prevents clear distinction of the impact of lockdown on BC and PM.