Mercury Oxidation and Depletion in the Reactive Halogen Enriched Troposphere of the Dead Sea

本研究的目的是阐明最近在以色列死海观测到的大气汞消耗事件（AMDE）的大气条件和化学途径。假设包括：(1)死海气态单质汞（GEM）的消耗伴随着活性气态汞（RGM）和颗粒形式汞（PHg）水平的增加，这将证实死海的AMDE与在极地对流层观测到的相似；(2) AMDE与高水平的活性卤素化合物（RHC），特别是BrOx （Br + BrO）相关；(3)即使是小浓度的RHC也可能引发GEM氧化，这对其他中纬度海洋边界层中RHC水平较低的地点有影响。这些假设将通过同时测量特定的汞、卤素氧化物、氮氧化物、臭氧、硫酸盐气溶胶、细颗粒物和气象参数来验证。建模研究将有助于确定反应性卤素化学和汞氧化的机制。了解大气汞种类的来源和汇强度对于监管机构保护人类和生态系统免受这种强效毒素的侵害至关重要。这项研究将涉及内华达大学里诺分校的本科生和研究生。将与当地（内华达州）学区建立合作伙伴关系，让教师和学生参与这项研究，并扩大与他们的天才计划的现有合作。

The aim of this study is to elucidate atmospheric conditions and chemical pathways responsible for recently observed atmospheric mercury depletion events (AMDE) at the Dead Sea in Israel. Hypotheses include: (1) depletion of gaseous elemental mercury (GEM) at the Dead Sea is accompanied by increased levels of reactive gaseous mercury (RGM) and particulate forms (PHg), which would confirm that AMDE at the Dead Sea are analogous to those observed in the polar troposphere; (2) AMDE are correlated with high levels of reactive halogen compounds (RHC), specifically BrOx (Br + BrO); (3) even small concentrations of RHC may initiate GEM oxidation, with implications for other midlatitude marine boundary layer sites with lower RHC levels. These hypotheses will be tested by simultaneous measurement of speciated mercury, halogen oxides, nitrogen oxides, ozone, sulfate aerosols, fine particulates, and meteorological parameters. A modeling study will help identify the mechanisms for reactive halogen chemistry and mercury oxidation.Knowledge of source and sink strengths of atmospheric mercury species is critical for regulatory agencies to protect humans and ecosystems from this potent toxin. The research will involve undergraduate and graduate students from the University of Nevada, Reno. A partnership will be initiated with a local (Nevada) school district to expose teachers and students to this research and expand a current collaboration with their Gifted and Talented Program.