Geographical Distribution of Atmospheric Nitrogen Deposition in China and Its Response to Emission Control Policy.

Atmospheric nitrogen (N) deposition has experienced significant change because of anthropogenic emissions, thereby exerting a pronounced impact on global ecosystem services. With the rapid development of industry and agriculture and the swift expansion of urban areas in China since the 1980s, reactive nitrogen (Nr) emissions and N deposition have substantially increased. In pursuit of improving air quality, China has implemented a series of environmental protection policies and undertaken diverse measures to reduce pollutant emissions. This paper is a review of multivariate data sources of atmospheric N deposition based on the results of literature from 1980 to 2023, and the original data from 1980 to 2020 are summarized, counted and calculated. The main findings are as follows: 1) the annual average atmospheric N deposition ranged from approximately 20–40 kg/(ha·yr), with the variability primarily linked to different assessment methods; 2) regional disparities were evident in the spatial distribution of N deposition, with elevated values concentrated in areas with intense Nr emissions; 3) atmospheric N deposition significantly declined after 2010, particularly the deposition of oxidized N, while reduced N deposition remained stable. These results reflect the effects of China's serious control policies on nitrogen oxide (NOx) emissions and strengthen the importance of agricultural NH3 emission mitigation. This study contributes to a comprehensive understanding of the N dynamics in the emission-deposition process, and provides a scientific foundation for the research of environmental protection, climate change, and sustainable development. [ABSTRACT FROM AUTHOR]