RUI: Chemical Characterization and Reactivity of Chromophoric Dissolved Organic Matter (CDOM) in Rainwater

本项目主要解决以下问题：(1)雨水中显色性溶解有机物（CDOM）的来源和化学特征是什么？(2) CDOM在光化学转化中的作用是什么？(3) CDOM在金属形态形成中的作用是什么？这些问题将通过各种工具进行研究，包括同位素分析、核磁共振和受控光解实验。为了进行分析，雨水CDOM样本将在不同的季节、风暴类型和地点收集。过氧化氢和其他小分子形成的速率和量子产率将通过光解实验来确定。还将评价CDOM氮对雨水中溶解有机氮的贡献。雨水CDOM可能是降水中碳的主要形式，该研究将为影响雨水CDOM来源、命运和大气影响的化学和物理因素提供新的信息。CDOM光化学影响太阳辐射的光谱衰减、对流层自由基化学、氧化能力、产酸能力和大气中痕量金属形态。更广泛的影响还包括每年教育和培训一名博士后研究员，两名硕士研究生，两名本科生和一名高中生。此外，每年将有一名当地高中科学教师参加这项研究，为期一个月。

This project addresses the questions: (1) What are the origin and chemical characteristics of chromophoric dissolved organic matter (CDOM) in rainwater? (2) What is CDOM's role in photochemical transformations? (3) What is CDOM's involvement in metal speciation? These questions will be studied with a variety of tools including isotopic analysis, NMR, and controlled photolysis experiments. For the analyses, rainwater CDOM samples will be collected during different seasons, storm types, and locations. The rates and quantum yields for the formation of hydrogen peroxide and other small molecules will be determined with photolysis experiments. The contribution of CDOM nitrogen to dissolved organic nitrogen in rainwater will also be assessed. This research will provide new information on the chemical and physical factors influencing sources, fate, and atmospheric impacts of rainwater CDOM, which may be the predominant form of carbon in precipitation. CDOM photochemistry affects the spectral attenuation of solar radiation, tropospheric free radical chemistry, oxidizing capacity, acid generating capacity, and trace metal speciation in the atmosphere. Broader impacts also include education and training of a post-doctoral researcher, two master's level graduate students, two undergraduates and one high school student each year. In addition, a local high school science teacher will participate in this research for one month each year.