The Analysis, Reactions and Growth of Aerosol Particles Studied by Vacuum UV Photoionization Mass Spectrometry

北卡罗来纳大学教堂山分校的Tomas Baer得到了实验物理化学计划和大气化学计划的支持，该计划利用真空紫外线(VUV)光来研究在实验室流管、反应室和室外烟雾室内产生的气溶胶中有机成分的复杂混合物。同步辐射、脉冲激光辐射和稀有气体共振灯形式的真空紫外光将被用于研究大粒子和小粒子。模型气溶胶的反应性将作为其形态的函数进行检查。包覆颗粒以及镶嵌在多孔颗粒中的有机物颗粒与臭氧的反应速率将在实验室中测量。主要的重点将是鉴定二次有机气溶胶中的有机成分和由气体-颗粒反应产生的物种。一种罕见的气体共振灯将被安装，以调查它在雾霾室内研究中检测小颗粒的用途，这些研究本身不利于脉冲激光电离。此外，先进光源的实验将在实验室反应室中进行受控成核研究。环境中许多自然产生的小颗粒是高度异质的，含有碳、盐、金属和有机分子的混合物。当这些颗粒与某些气体接触时，发生的化学反应将受到颗粒性质的影响。该项目将开发研究气溶胶颗粒的新实验方法。此外，新方法将被用来检查模拟真实世界环境系统的受控大气中气溶胶的形成。这项研究将由学生和博士后助理进行，他们将接受物理、分析和环境化学方面的广泛培训。

Tomas Baer of the University of North Carolina at Chapel Hill is supported by The Experimental Physical Chemistry Program and the Atmospheric Chemistry Program to employ vacuum ultraviolet (VUV) light to investigate complex mixtures of organic constituents in aerosols generated in laboratory flow tubes, reaction chambers, and in an outdoor smog chamber. VUV light in the form of synchrotron radiation, pulsed laser-generated radiation, and rare gas resonance lamps will be utilized to study both large and small particles. The reactivity of model aerosols will be examined as a function of their morphology. The reaction rates of coated particles as well as particles consisting of organics embedded in porous particles with ozone will be measured in the laboratory. A major emphasis will be on identification of organic constituents in secondary organic aerosols and species generated by gas-particle reactions. A rare gas resonance lamp will be installed to investigate its use for detecting small particles in smog chamber studies that do not lend themselves to pulsed laser ionization. As well, experiments at the Advanced Light Source will be directed at controlled nucleation studies in a laboratory reaction chamber. Many naturally occurring small particles in the environment are highly heterogeneous, containing mixtures of carbon, salts, metals, and organic molecules. When these particles are in contact with certain gases, the chemical reactions that occur will be affected by the particle properties. New experimental methods to study aerosol particles will be developed in this project. In addition, the new methods will be used to examine aerosol formation in controlled atmospheres that mimic real-world environmental systems. This research will be carried out by students and postdoctoral associates, who will be broadly trained in physical, analytical, and environmental chemistry.