The Response of Nitrogen Deposition in China to Recent and Future Changes in Anthropogenic Emissions
Hanzheng Zhu, Youfan Chen, Yuanhong Zhao, Lin Zhang, Xilong Zhang, Bo Zheng, Lei Liu, Yuepeng Pan, Wen Xu, Xuejun Liu
Abstract
Abstract We 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 (NH x ) during 2007–2015 is dominated by the decrease in sulfur dioxides (SO 2 ) emissions, which reduces the formation of ammonium (NH 4 + ) aerosols from gas‐phase ammonia (NH 3 ). Although the decrease in SO 2 emissions led to conversion from wet to dry deposition of NH x , the NH 4 + wet deposition increased by 0.75 Tg N yr −1 with large interannual variations driven by precipitation. Different from NH x , the oxidized nitrogen (NO y ) 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 (NO x ) emissions. Based on the national scale emission‐deposition relationship estimated from model sensitivity experiments, we find that future emission control would reduce the NO y 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 NH x deposition in China from 2015 to 2030. The decrease in NO x and SO 2 emissions under future scenarios would enhance the NH x dry deposition over domestic China, diminishing the effectiveness of the NH 3 emission control. The results emphasize that stricter strategies for controlling agricultural NH 3 emissions should be taken to alleviate the adverse environmental impacts from atmospheric nitrogen deposition.