What drives anthropogenic fine particulate chloride emissions in India? - A quantitative assessment of hotspots

Particulate chloride (pCl) is a significant constituent of atmospheric particulate matter, playing a critical role as a key precursor to secondary aerosols via nocturnal heterogeneous reactions. While coarse pCl typically prevails along the coastal belt, however, the growing presence of fine pCl in the interior regions is an emerging air quality concern. Anthropogenic sources driving these emissions remain poorly characterised, particularly in India, where existing global inventories lack resolution and specificity. This study presents the first high-resolution (0.1° × 0.1°) national anthropogenic emission inventory of pCl across India for 2023, identifying 42 discrete sources. Total pCl emissions are estimated at 245.6 Gg/yr, of which biomass burning contributes ~68 % and waste burning ~21 %. Emission hotspots are concentrated in the northern and southern Indo-Gangetic Plain and the Northeastern states, with over 60 % of total emissions originating from just 8 % of the country's area. Despite an estimated uncertainty of ±71 %, this comprehensive dataset offers critical insights for chemical transport modelling and policy formulation, enabling targeted mitigation strategies and advancing understanding of pCl dynamics at the national level.