The Response of Nitrogen Deposition in China to Recent and Future Changes in Anthropogenic Emissions

Abstract

AbstractWe present a model analysis that quantifies the influence of anthropogenic emission variations on the recent (2005–2015) and future (2030) changes in national scale nitrogen deposition in China and the interacting relationships between their emissions and depositions. We find that the 0.39 Tg N yr−1 increase in the dry deposition of reduced nitrogen (NHx) during 2007–2015 is dominated by the decrease in sulfur dioxides (SO2) emissions, which reduces the formation of ammonium (NH4+) aerosols from gas‐phase ammonia (NH3). Although the decrease in SO2 emissions led to conversion from wet to dry deposition of NHx, the NH4+ wet deposition increased by 0.75 Tg N yr−1 with large interannual variations driven by precipitation. Different from NHx, the oxidized nitrogen (NOy) deposition increased by 1.6 Tg N yr−1 from 2005 to 2011 and decreased by 1.1 Tg N yr−1 from 2011 to 2015, following the changes in nitrogen oxides (NOx) emissions. Based on the national scale emission‐deposition relationship estimated from model sensitivity experiments, we find that future emission control would reduce the NOy deposition by 2.4 ± 0.08 to 3.4 ± 0.12 Tg N yr−1 (49%–73%), but only lead to small decreases of 0.93 ± 0.05 to 1.2 ± 0.06 Tg N yr−1 (9%–14%) in NHx deposition in China from 2015 to 2030. The decrease in NOx and SO2 emissions under future scenarios would enhance the NHx dry deposition over domestic China, diminishing the effectiveness of the NH3 emission control. The results emphasize that stricter strategies for controlling agricultural NH3 emissions should be taken to alleviate the adverse environmental impacts from atmospheric nitrogen deposition.