Development of Photofragmentation Laser Induced Fluorescence Sensor for Measurements of CH31 in the Marine Boundary Layer

环境地球化学和生物地球化学项目的这个奖项是由大气科学部和化学部以及MPS多学科活动办公室共同支持的。佐治亚理工学院地球与大气科学学院的Scott T. Sandholm博士将开发一种光破碎激光诱导荧光传感器（pf - liff），用于测量海洋边界层中挥发性甲基碘。目前有机碘化物的检测方法严重依赖于对储存的“抓取”样品的分析，并且对样品的制备和处理以及热降解非常敏感。LIF传感器将允许现场测量甲基碘化物和其他简单有机碘化物从海洋和沿海地区排放到大气的时间分布。期望该方法具有有效所需的灵敏度和选择性。有机碘化物在光破碎动力学方面的相似性，使得可以通过跟踪已知从海洋源排放的所有有机碘化物原子碘的累积光破碎产生I*来测量总碘发射。由于缺乏对源化合物的定量测量，碘在对流层和平流层臭氧循环中的作用尚未得到很好的了解。有机碘化合物被认为是从海洋中蒸发出来的，是碘的来源。在这项研究中，将开发一种直接测量碘的新方法，并在格鲁吉亚沿海的实地部署中进行测试。

This award in the Environmental Geochemistry and Biogeochemistry Program is jointly supported by the Divisions of Atmospheric Science and Chemistry and by the MPS Office of Multidisciplinary Activities. Dr. Scott T. Sandholm of the School of Earth and Atmospheric Sciences, Georgia Institute of Technology, will develop a photofragmentation laser induced fluorescence sensor (PF-LIF) to measure volatile methyl iodide in situ in the marine boundary layer. Current detection methods for organic iodides rely heavily on analysis of stored `grab` samples and can be quite sensitive to preparation and handling of samples and to thermal degradation. The LIF sensor will permit in situ measurements as well as temporal emission profiles of methyl iodide and other simple organic iodides to the atmosphere from oceanic and coastal regions. The method is expected to have the sensitivity and selectivity needed to be effective. The similarities in photofragmentation dynamics of organic iodides enables total iodine emission to be measured by following the cumulative photofragmented production of atomic iodine as I* for all organic iodides known to be emitted from oceanic sources. The role of iodine in tropospheric and stratospheric ozone cycles is not well understood due to lack of quantitative measurements of the source compounds. Organic iodide compounds are thought to evaporate from the ocean and serve as a source. In this research, a new method for direct measurement of iodine will be developed and tested in field deployment off the coast of Georgia.