Work

Optimizing ammonia emissions for PM 2.5 mitigation: environmental and health co-benefits in Eastern China

Year: 2025

Type: article

Abstract: . Ammonia (NH3) is a key precursor of PM2.5, contributing to the formation of secondary inorganic aerosols and playing a crucial role in haze events. However, current bottom-up emission inventories in China often underestimate NH3 emissions, particularly with significant uncertainties in urban areas. This study developed a "top-down" iterative algorithm that integrates the IASI satellite observations with the WRF-Chem model to optimize bottom-up NH3 emissions, and further quantified the impacts of source-specific emission reductions on PM2.5 pollution. The result reveals that the updated NH3 emissions in Eastern China for 2016 amounted to 4.2 Tg·yr-1, 27.3 % higher than prior estimations. The optimized NH3 emissions peak in summer at 463.1 Gg·mon-1, with agricultural sources accounting for 85 %, while winter emissions drop to 217 Gg·mon-1 when the contribution from non-agricultural sources (e.g., industry, vehicle) significantly increases. The optimized NH3 emission significantly improved the simulated results of NH3 concentration, both in terms of magnitude (31 %~42 %) and variations (17 %~55 %). Sensitivity simulations show that a 30 %~60 % reduction in NH3 emission led to decreases of 1.5~8.8 μg·m-3 in city-level PM2.5 concentrations and the potential effect of reducing non-agricultural emissions is comparable with that from agricultural sources. Furthermore, the NH3 reduction positively impacts public health, resulting in a 6.5 %~10.3 % decrease in premature deaths attributed to PM2.5 exposure. These findings provide strong data support for air quality research and offer valuable insights into the potential air quality and public health benefits of NH3 emission reduction.

Source: Atmospheric chemistry and physics

DOI: 10.5194/acp-25-14747-2025