Modeling regional nitrogen cycle in the atmosphere: Present situation and its response to the future emissions control strategy

Ao Shen; Yiming Liu; Xiao Lu; Yifei Xu; Yinbao Jin; Haofan Wang; Juan Zhang; Xuemei Wang; Ming Chang; Qi Fan

doi:10.1016/j.scitotenv.2023.164379

Modeling regional nitrogen cycle in the atmosphere: Present situation and its response to the future emissions control strategy

Sci Total Environ. 2023 Sep 15:891:164379. doi: 10.1016/j.scitotenv.2023.164379. Epub 2023 May 20.

Authors

Ao Shen¹, Yiming Liu², Xiao Lu¹, Yifei Xu¹, Yinbao Jin¹, Haofan Wang¹, Juan Zhang¹, Xuemei Wang³, Ming Chang³, Qi Fan⁴

Affiliations

¹ School of Atmospheric Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Zhuhai 510982, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou 510275, China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-Sen University, Zhuhai 510982, China.
² School of Atmospheric Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Zhuhai 510982, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou 510275, China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-Sen University, Zhuhai 510982, China. Electronic address: liuym88@mail.sysu.edu.cn.
³ Institute for Environmental and Climate Research, Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Jinan University, Guangzhou 511443, China.
⁴ School of Atmospheric Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Zhuhai 510982, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou 510275, China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-Sen University, Zhuhai 510982, China. Electronic address: eesfq@mail.sysu.edu.cn.

PMID: 37216993
DOI: 10.1016/j.scitotenv.2023.164379

Abstract

Reactive nitrogen (Nr) cycle in the atmosphere has an important affection on terrestrial ecosystems, which has not been fully understood and its response to the future emissions control strategy is not clear. Taking the Yangtze River Delta (YRD) as an example, we explored the regional Nr cycle (emissions, concentrations, and depositions) and its source apportionment in the atmosphere in January (winter) and July (summer) 2015 and projected its changes under emissions control by 2030 using the CMAQ model. We examined the characteristics of Nr cycle and found that Nr suspends in the air mainly as NO, NO₂, and NH₃ gases and deposits to the earth's surface mainly as HNO₃, NH₃, NO₃^-, and NH₄⁺. Due to the higher NO_x than NH₃ emissions, oxidized nitrogen (OXN) but not reduced nitrogen (RDN) is the major component in Nr concentration and deposition, especially in January. Nr concentration and deposition show an inverse correlation, with a high concentration in January and low in July but the opposite for deposition. We further apportioned the regional Nr sources for both concentration and deposition using the Integrated Source Apportionment Method (ISAM) incorporated in the CMAQ model. It shows that local emissions are the major contributors and this characteristic is more significant in concentration than deposition, for RDN than OXN species, and in July than in January. The contribution from North China (NC) is important for Nr in YRD, especially in January. In addition, we revealed the response of Nr concentration and deposition to the emission control to achieve the target of carbon peak in the year 2030. After the emission reduction, the relative responses of OXN concentration and deposition are generally about 100 % to the reduction of NO_x emissions (~50 %), while the relative responses of RDN concentration are higher than 100 % and the relative responses of RDN deposition are significantly lower than 100 % to the reduction of NH₃ emissions (~22 %). Consequently, RDN will become the major component in Nr deposition. The smaller reduction of RDN wet deposition than sulfur wet deposition and OXN wet deposition will raise the pH of precipitation and help alleviate the acid rain problem, especially in July.

Keywords: CMAQ-ISAM; Future emission control; Nitrogen cycle; Regional source attributions; The Yangtze River Delta.