Collaborative Research: Photochemical Production of Radical Oxidants and Hydroperoxides from Organic Matter and Nitrate in Sea-Salt Aerosols

这项合作奖涉及系统地研究和评估羟基自由基和过氧化氢的产生在阳光与海洋边界层中发现的气溶胶相互作用中的重要性。人们认识到，在这些颗粒中常见的硝酸根离子和有机化合物被太阳辐射分解，导致氧化化合物的产生，但这种认识并不伴随着定量的理解。这项研究将部署一种设备来制造新鲜的海洋气雾剂，这种气雾剂将经过仔细的表征并暴露在阳光下。酸度、温度和气溶胶量等控制变量将被系统地改变，以帮助量化和测试这些次级氧化物种产生的可能机制。然后，将对环境气溶胶进行类似的实验，这将更加复杂，因为它们很可能在大气中经历了一些变化。这项研究的结果将被纳入一个旨在量化对流层中气溶胶和气相化学过程的模型，以评估这些过程的重要性。在这项研究的过程中，博士后研究员以及研究生和本科生将参与其中。这项工作为许多国家和国际计划的目标和活动做出了贡献，其中包括表层海洋-低层大气研究(SOLAS)、国际全球大气化学(IGAC)和国家气溶胶-气候相互作用计划(NACIP)。

This collaborative award involves the systematic study and assessment of the importance of hydroxyl radical and hydrogen peroxide production in the interaction of sunlight with aerosols that are found in the marine boundary layer. It is recognized that the breakdown of nitrate ions and organic compounds, commonly found in these particles, by solar radiation leads to the production of oxidized compounds, but this recognition is not accompanied by quantitative understanding. This study will deploy an apparatus to make fresh marine aerosols that will be carefully characterized and exposed to sunlight. Controlling variables such as acidity, temperature, and aerosol amount will be changed systematically to help quantify and test possible mechanisms of the production of these secondary oxidized species. Then similar experiments will be performed with ambient aerosols, which will be somewhat more complicated because they will likely have undergone some transformations during their time in the atmosphere. The results of this study will be incorporated into a model designed to quantify aerosols and gas phase chemical processes in the troposphere in order to assess the importance of these processes.During the course of this research a post-doctoral fellow as well as graduate and undergraduate students will participate. This work contributes to the goals and activities of a number of national and international programs including the Surface Ocean - Lower Atmosphere Study (SOLAS), International Global Atmospheric Chemistry (IGAC) and National Aerosol-Climate Interactions Program (NACIP).