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

这项研究的目的是阐明最近在以色列死海观测到的大气汞耗竭事件(AMDE)的大气条件和化学途径。假设包括：(1)死海气态元素汞(GEM)的枯竭伴随着活性气态汞(RGM)和颗粒形态(PHG)水平的增加，这将证实死海的AMDE类似于在极地对流层中观察到的；(2)AMDE与高水平的活性卤素化合物(RHC)有关，特别是Brox(BrBrO)；(3)即使是低浓度的RHC也可引发GEM氧化，影响到其他RHC水平较低的中纬度海洋边界层站点。这些假设将通过同时测量形态汞、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检验。模拟研究将有助于确定活性卤素化学和汞氧化的机制。了解大气汞物种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烈毒素的伤害至关重要。这项研究将涉及来自里诺内华达大学的本科生和研究生。将与当地(内华达州)学区建立伙伴关系，让教师和学生接触到这项研究，并扩大目前与他们的天赋和才华计划的合作。

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.