A Laboratory Study to Investigate Inorganic and Organic Sulfate Formation in Multiphase Processes Involving Mineral Dust and Other Metal-Containing Aerosols

该项目的重点是实验室研究，以更好地了解大气中二氧化硫氧化形成的颗粒硫酸盐。拟议研究的一个主要重点将是量化矿物粉尘和其他含金属气溶胶多相途径中硫酸盐形成的速度和程度随pH、温度和光照的变化。硫酸盐形成的机理将通过一系列实验室研究来探讨，这些研究包括：(1)矿物和人为含金属粉尘中过渡金属离子的催化作用；(2)在光活性半导体氧化物存在下促进硫酸盐的形成；以及(3)有机化合物在矿物介导的硫酸盐过程中的作用。此外，还将开发研究单个云滴内部化学的新方法，包括带有腔增强拉曼光谱的光钳，用于研究含有尘埃包裹体的微米级单个液滴中的硫氧化化学。这些实验将在存在和不存在对大气具有重要意义的有机物种的情况下进行，这些有机物种可以反应生成有机硫酸盐。该项目还将评估表面反应性与整体反应性的重要性，这对于模拟云过程很重要。

This project focuses on laboratory studies to better understand particulate sulfate formation from sulfur dioxide oxidation in the atmosphere. A major focus of the proposed studies will be to quantify rates and extent of sulfate formation in multiphase pathways involving mineral dust and other metal-containing aerosols as a function of pH, temperature and light.The mechanisms for sulfate formation that will be investigated in a series of laboratory studies that include the: (1) catalytic effects of transition metal ions present in mineral and anthropogenic metal-containing dusts; (2) enhanced sulfate formation in the presence of photoactive semiconductor oxides; and (3) role of organic compounds in mineral mediated sulfate processes. In addition, new methods to investigate the chemistry within individual cloud droplets will be developed, including an optical tweezer with cavity enhanced Raman spectroscopy to investigate sulfur oxidation chemistry within micron sized single droplets containing a dust inclusion. The experiments will be done in the presence and absence of atmospherically important organic species that can react to yield organosulfates. This project will also assess the importance of surface reactivity versus bulk reactivity, important for modeling cloud processes.