有机物促进成核机制与离子诱导成核机制协同效应研究

The New Particle Formation (NPF) is an important source of particulate matter in the atmosphere and cloud condensation nuclei. Although aerosol measurement techniques have been developing rapidly, the ability to detect and characterize sub-3 nm (the key point of nucleation stage) clusters remains limited. In all the existing nucleation mechanisms, the importance of Organics Enhanced Nucleation (OEN) and Ion Induced Nucleation (IIN) has been confirmed. As recent research shows, organics and Ions, such as organic carboxylic acid and hydrogen sulfate ion, play an important role in the aerosol nucleation. However, the nucleation mechanisms above mentioned are usually studied separately, which results in the absence of comprehensive interpretation of the aerosol nucleation in the complex atmosphere. In order to give a more accurate view of aerosol nucleation, research of the synergistic effect between Organics Enhanced Nucleation and Ion Induced Nucleation is a task which brooks no delay. Therefore, in this program, through Mass Spectrometric and Infrared-Photo Dissociation, the research is focused on the influence from organic carboxylic acid and hydrogen sulfate ion on the stability of sulfuric acid-water clusters and nucleation rate, in the sight of physics and chemistry. Combining with the high accuracy quantum chemical calculation, we will study the interaction between the influences from organic carboxylic acid and hydrogen sulfate ion to explore the synergistic effect between Organics Enhanced Nucleation and Ion Induced Nucleation and measure their contributions to the aerosol nucleation.

新粒子的生成是大气中颗粒物和云凝结核的重要来源。目前对新粒子生成的研究主要集中在3 nm以上的生长阶段，而对于关键的生成临界核的成核阶段(< 3 nm)还缺乏系统的研究。在目前已有的成核机制中，“有机物促进成核”和“离子诱导成核”的重要性得到确认，其中，现有研究已表明，以有机羧酸和硫酸氢根离子分别为代表的有机物和离子在气溶胶成核中具有重要作用。但以上成核机制往往只是被单独研究使用，而针对复杂的大气环境，单一的某种成核机制难以全面的解释成核事件，各类成核机制之间的协同效应还有待于进一步的研究。因此，本项目研究主要利用物理化学的手段，采用质谱和红外光解离振动谱，并结合高精度量子化学计算方法，以有机羧酸和硫酸氢根离子为例，从微观角度研究其在大气中对硫酸-水团簇的稳定性及成核速率的影响，同时，进一步对比两种成核机制，研究两者之间的协同效应，以及在大气气溶胶成核事件中所占的贡献大小。

新粒子生成是大气气溶胶和云凝结成核的重要来源，通过直接或间接方式影响地球辐射平衡、全球气候变化和人类健康。然而，由于全球大气环境的多样性以及目前检测手段的局限性，人们对新粒子生成机理的理解尚不清晰，尤其是新粒子生成初期气相物质生成临界核团簇的过程，因此深入了解各成核机制的特性并加强对各成核机制之间协同效应的研究对了解雾霾形成机制以及预防也起到关键性作用。本项目主要采用物理化学手段，通过搭建离子诱导成核实验平台及流动管实验平台，并结合高精度量子化学计算，对有机物促进成核机制和离子诱导成核机制进行基础研究，获得两种气溶胶成核机制之间的协同效应。