典型低挥发性有机物大气氧化反应与SOA形成机制研究

Secondary organic aerosol (SOA), which accounts for a significant fraction of fine particle (PM2.5) in atmosphere, not only has important impliations for global or regional climate, visibility and human health, but also been believed to be related tightly with intensive haze events in China. Although SOA formed from gas-phase oxidation of volatile organic compounds (VOCs) has been believed as an important source of OA both on global and local scales, the relative contribution of SOA to the overall OA budget remains controversial. For example, the amount of OA observed in urban sites is consistently higher than that for which volatile SOA precursors can account based on the reaserch of laboratory and model. So to rethink thoroughly the source of SOA and the formation mechnism is pivotal to learn the environmental effect of SOA. Based on the reasearch platform of in-door simulation reactor(smog chamber and flow reactor), the oxidation of the typical low-volatility organic compounds (LVOCs) will be studied in this project. By taking the full advantage of "soft" ionization and the capability of discriminating chemical components of the compounds with the same M/Z of synchrotron radiation photoionization mass spectrometry, and the other dectection methods as well, atmospheric oxidation of different types (polycyclic aromatic hydrocarbons and long n-alkanes), different phase(gas phase/particle phase) of LVOCs, as well as real exhaust gas from engine will be investigated qualitatively and quantitatively. It is believed that this project will contribute to the deep understand of the source and the formation mechinsm of SOA and is also profound to the control and prevention of haze in China.

二次有机气溶胶（SOA）是PM2.5的重要组成部分，它不仅影响着全球或区域气候变化、大气能见度和人类健康，还是中国城市和区域性灰霾日益加剧的重要诱因之一。鉴于现有的实验室研究和模型研究（主要以大气中挥发性有机物（VOCs）为研究对象）还难以正确和全面地评估实际大气中SOA的形成及演化，本项目拟基于实验室模拟反应研究平台，针对城市大气中具有典型代表性的低挥发性有机物（LVOCs）的大气氧化反应体系开展相关研究。充分利用同步辐射真空紫外光电离质谱的“软电离”以及能在线分辨同分异构体等独特优点，并结合其它多相、多组分探测技术，通过对相关反应气相或粒子相产物的探测与分析，深入探究不同种类、不同形态的LVOCs以及实际发动机尾气大气氧化反应机制及相应SOA的产生与演化过程。本项目的开展不仅有助于准确全面地评估大气SOA源解析和形成机理，也将为减少和控制我国城市大气污染提供科学依据。

二次有机气溶胶（SOA）是大气环境、气候变化和人类健康的重要影响因素之一。然而现有的主要以大气挥发性有机物（VOCs）氧化反应为研究对象的研究结果还难以正确和全面地评估实际大气中SOA的形成机制及演化规律。本项目基于自行搭建的实验室模拟反应系统（烟雾箱和流动反应池），并结合同步辐射真空紫外光电离气溶胶质谱等检测系统，研究了城市大气中具有典型代表性的低挥发性有机物（LVOCs）的大气氧化反应与SOA的形成。通过利用同步辐射真空紫外光电离质谱“软电离”的独特优点，对典型多环芳烃（如1-甲基萘）、典型中长链烷烃（正十六烷）和烯烃（角鲨烯）氧化反应产生的SOA进行了化学组分在线分析；同时利用气溶胶粒径探测系统定量研究了不同环境因素对相关反应生成SOA的影响效应。. 本项目的开展不仅进一步证实了LVOCS的大气氧化反应是大气中SOA的潜在来源，为准确全面地评估大气SOA源解析和形成机理提供科学依据，同时相关研究方法与技术的发展也为大气气溶胶的相关研究提供了新的手段，有利于推进未来大气气溶胶的相关研究。