Spatio-temporal distribution of INSAT-3D AOD derived particulate matter concentration over India

Abstract

Ground observations over 60–80 sites in India during 2014–18 reveal that Particulate Matter (PM) concentration exceeded National Ambient Air Quality Standard (NAAQS) by 1.5–2.5 times during Pre-Monsoon (PrM), Post-Monsoon (PoM) and Winter (Win) seasons only. Geographically Weighted Regression technique was employed to estimate PM2.5 and PM10 incorporating Aerosol Optical Depth (AOD) measured from geostationary orbit by Indian National Satellite (INSAT-3D) and ERA-INTERIM derived meteorological parameters. INSAT-3DAOD was well correlated with ground measured AOD (R2 > 0.75). Estimated PM found higher during PrM (PM2.5: 103.16 ± 31.39 μg m−3, PM10: 150.07 ± 43.13 μg m−3) than PoM (PM2.5: 58.72 ± 22.9 μg m−3, PM10: 127.17 ± 48.95 μg m−3) and Win (PM2.5: 71.02 ± 20.25 μg m−3, PM10: 96.86 ± 27.63 μg m−3). PM pollution was severe in West India (PM2.5: 87.44 ± 30.07 μg m−3, PM10: 148.13 ± 42.8 μg m−3), 1.2–1.5 times higher than least polluted North-East India. Spatial variability of PM distinctly discern the major prone areas that experience episodic events like dust (PM10 > 150 μg m−3) and biomass burning (PM2.5 >100 μg m−3). Overall country registered increase in AOD, PM10, PM2.5 by 52.34%, 36.23%, 36.58% respectively. Estimation accuracy produced by the model was satisfactory (R2 > 0.6; NMSE <0.25; −0.01 < FB < 0.09). The human footprint perceived by the PM2.5/PM10 ratio signifies that 60.95% PM10 is attributed to PM2.5 across the country and it was highest during Win (73.45%). The changes in spatial distribution of PM highlight that Indo-Gangetic Plain and coastal area in Southern India had undergone major industrialization, urban expansions which resulted in increase of PM2.5 by 50–125 μg m−3 during all seasons.