出版社：Chinese Association for Aerosol Research in Taiwan
摘要：Air pollution in India, especially in cities located in Indo-Gangetic plain (IGP), has exceeded allstandards in the recent past. The development of an effective pollution control strategy requiresknowledge of the pollutant sources, their spatio-temporal variability, and the efficacy of controlstrategies. The Indian government has implemented nationwide lockdown (LD) during March andApril 2020 to contain the infectious disease COVID-19. LD also provides an opportunity toevaluate the efficacy of restricting anthropogenic activities in controlling air pollution. In thepresent paper, using data from space-borne sensors, a detailed analysis of the impact of LD onaerosols in the Indian atmosphere is presented. The aerosol optical depth (AOD), fine modefraction (FMF), absorbing aerosol index (AAI), active fire/thermal anomaly and the HYSPLIT modelis used to study the instantaneous state and spatio-temporal transportation of aerosols. Onaverage, an overall decrease in AOD with 60% of the Indian landmass showing an averagedecrease of 0.16 is observed. A significant decrease in FMF indorses decreased AOD solely dueto restricted anthropogenic activities, especially in IGP, which confirms the positive impact of LDon air quality. However, central, northeast and partially western India show some contrastingresults which are associated with smoke from active fires. An increase of 30% in fire spots isobserved during LD in these regions. The city-level analysis shows improved air quality in most ofthe cities located in IGP during LD. The cities located in the west, north-west and east India haveshown a small decrease in AOD during LD, while in central, north-east, and few in the southernregion, the increased AOD is observed in spite of LD due to increase in biomass burning.
