酸性物质输送及沉降过程中大气氨转化作用机制研究

大气中的氨是产生和影响酸沉降的关键前体物之一，可与硫酸气和硝酸气等结合产生铵盐气溶胶，是细颗粒物PM2.5的主要组分，能够影响云凝结核的形成、改变辐射强迫，影响生态环境和人体健康。目前在线测量技术的发展，极大地促进了国际上针对大气氨的分布特征和演变规律以及其对气溶胶生成途径的影响等研究。然而，系统地研究大气氨对区域性灰霾污染的贡献，特别是在气溶胶粒径分布、辐射反馈效应以及沉降等方面的研究相对较少，尚缺乏定量的分析和阐述。本项目拟通过在京津冀地区开展针对大气氨、气溶胶无机化学组分、粒径分布以及消光特性等要素的综合观测，研究其在酸性物质的转化、输送以及沉降过程中的作用机制，判断气粒平衡体系中大气氨的过量程度，获取关键影响因子。同时，结合数值模式定量分析大气氨对不同形态干、湿沉降通量及长距离输送的影响。研究成果对区域大气灰霾治理和酸沉降的生态环境管理具有重要的参考价值。

Ammonia (NH3) in the atmosphere significantly affects acidic deposition by reacting with acidic species such as sulfuric acid and nitric acid to form ammonium salts, which are the major components of aerosol particles. Aerosols have great impacts on cloud condensation nuclei, atmospheric visibility, radiation forcing as well as ecosystems and human health. With the rapid development of online measurement techniques, it is now of great interest to study the distribution and variation of NH3 as well as its role in aerosol formation mechanism. However, only a few studies address the issue of how NH3 influences regional haze pollution on aerosol size distribution, radiation feedback and deposition, and even less is about quantitative analysis. In this study, comprehensive observations of NH3 together with inorganic components, size distribution and extinction of aerosol will be carried out to identify the key factors that affect aerosol formation and hence regional haze pollution. By incorporating 3-D numerical simulations, the influence of NH3 on the long-range acid transport and deposition can be quantified. The results will thus provide some scientific basis for government regulations aiming to reduce regional haze, acid deposition and ultimately improve the ecosystem and environment.