Anthropogenic Emissions of Hydrogen Chloride and Fine Particulate Chloride in China

Particulate chloride (Cl^-) can be transformed to nitryl chloride (ClNO₂) via heterogeneous reaction with nitrogen pentoxide (N₂O₅) at night. Photolysis of ClNO₂ and subsequent reactions of chlorine radical with other gases can significantly affect the atmospheric photochemistry. In China, the only available integrated anthropogenic chloride emission inventory was compiled in the 1990s with low spatial resolution, which hinders assessment of impact of ClNO₂ on current air quality. In this study, we developed an up-to-date and high-resolution anthropogenic inventory of hydrogen chloride (HCl) and fine particulate Cl^- emissions in China for 2014 with 0.1° × 0.1° resolution. Detailed local data and county-level activity data were collected and complied. The anthropogenic emissions of HCl and fine particulate Cl^- in 2014 were estimated to be 458 and 486 Gg, respectively. Biomass burning was the largest contributor, accounting for 75% of fine particulate Cl^- emission and 32% of HCl emission. Northeast China and North China Plain were the largest chloride emitters. The monthly distribution varied in different regions, due to different agricultural activities and climate conditions. This work updates the chloride emission information and improves its spatial and temporal resolution, which enables better quantification of the ClNO₂ production and its impact over China.