Abstract ID: 3.11813 | Accepted as Talk | Talk | TBA | TBA

The Himalayan region, adjacent to the highly polluted Indo-Gangetic Plain (IGP), has experienced rising air pollution due to emissions from construction, vehicles, industry, and biomass burning. These sources contribute significantly to aerosols in the high-altitude Himalayas. This study examines long-term (2000-2022) aerosol pollution scenarios using MODIS AOD, Ångström Exponent, and MERRA-2 data to assess aerosol loading and its trends, source regions, and dominant aerosol types. The lower IGP is the most polluted hotspot (0.64±0.09), followed by the middle (0.60±0.10) and upper IGP (0.49±0.10), while the central Himalayas show higher AOD (0.028±0.08) than other Himalayan parts. AOD trends (yr⁻¹) show an increasing pattern in IGP (lower: ~0.016, middle: ~0.01, upper: ~0.004), whereas Himalayan regions exhibit minimal variation (~0.001-0.003). Carbonaceous (Black Carbon, Organic Carbon) and Sulphate (SO₄²⁻) aerosols show rising trends in the lower IGP and eastern Himalayas (within Himalayas), with stronger increases in the 2000s than in the 2010s, though (%) changes are higher in the 2010s. Dust aerosols follow an opposite decadal trend. Concentration-weighted trajectory (CWT) and cluster analysis identify western/north-western regions and upper IGP as key aerosol sources for the western Himalayas. The middle IGP, along with these regions, contributes to central Himalayan pollution, while lower IGP, North-East India, and intra-Himalayan transport affect the eastern Himalayas. MODIS AOD-Ångström Exponent analysis reveals increase in biomass burning/urban industrial (BB/UI) aerosols in central and eastern Himalayas from the 2000s to 2010s. BB/UI aerosols dominate the IGP and North-East India, increasing by 7-10% during 2010s. Controlling emissions in the highly polluted IGP region is crucial to mitigating aerosol pollution in the fragile Himalayan region.