02468nas a2200205   4500000000100000008004100001653000700042653001700049653002900066100001700095700002300112700002300135700001900158700001600177700001900193245012400212856007200336520184000408022001402248       2021                            d10aPM10aBlack carbon10aBeta Attenuation Monitor1 aV. Sreekanth1 aMeenakshi Kushwaha1 aPadmavati Kulkarni1 aAdithi Upadhya1 aB. Spandana1 aVignesh Prabhu00aImpact of COVID-19 lockdown on the fine particulate matter concentration levels: Results from Bengaluru megacity, India  uhttps://www.sciencedirect.com/science/article/pii/S02731177210005453 aLeveraging the COVID-19 India-wide lockdown situation, the present study attempts to quantify the reduction in the ambient fine particulate matter concentrations during the lockdown (compared with that of the pre-lockdown period), owing to the highly reduced specific anthropogenic activities and thereby pollutant emissions. The study was conducted over Bengaluru (India), using PM2.5 (mass concentration of particulate matter having size less than or equal to 2.5 µm) and Black Carbon mass concentration (BC) data. Open-access datasets from pollution control board (PCB) were also utilised to understand the spatial variability and region-specific reduction in PM2.5 across the city. The highest percentage reduction was observed in BCff (black carbon attributable to fossil fuel combustion), followed by total BC and PM2.5. No decrease in BCbb (black carbon attributable to wood/biomass burning) was observed, suggesting unaltered wood-based cooking activities and biomass-burning (local/regional) throughout the study period. Results support the general understanding of multi-source (natural and anthropogenic) nature of PM2.5 in contrast to limited-source (combustion based) nature of BC. The diurnal amplitudes in BC and BCff were reduced, while they remained almost the same for PM2.5 and BCbb. Analysis of PCB data reveal the highest reduction in PM2.5 in an industrial cluster area. The current lockdown situation acted as a natural model to understand the role of a few major anthropogenic activities (viz., traffic, construction, industries related to non-essential goods, etc.) in enhancing the background fine particulate matter levels. Contemporary studies reporting reduction in surface fine particulate matter and satellite retrieved columnar Aerosol Optical Depth (AOD) during COVID-19 lockdown period are discussed.  a0273-1177