Collaborative Research: Verification of Atmospheric Mercury Redox Rates

合作研究：大气汞氧化还原率的验证

• 批准号: 2321379
• 负责人: Sarrah Dunham-Cheatham
• 金额: $ 23.54万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2321379&HistoricalAwards=false
• 关键词: Collaborative; Research; Verification; Atmospheric; Mercury

The cross-institutional collaborative investigators in this project will provide a new comprehensive dataset of compounds involved in the oxidation of mercury in the atmosphere by quantitatively measuring divalent mercury compounds, which are the more water-soluble forms of mercury. Mercury is emitted into the atmosphere in the elemental state, which undergoes various reactions with atmospheric oxidants into the divalent form, but there exist many uncertainties about which oxidant species and what rates these reactions occur. The primary objective of this project is to use these new measurements of speciated mercury, along with previous measurements, to quantitatively characterize both the speciation of mercury and the radical budget of sampled plumes in the Salt Lake City region nearby a magnesium mining facility (U.S. Magnesium). Two graduate students will be trained over the course of this project, and the project team plans on providing policy makers with updated information pertaining to mercury chemistry and the impacts on human health. The team also has plans to engage with state regulators to potentially extend the societal benefits of the knowledge gained.A recent discovery pertaining to standard measurement techniques has revealed a systematic low bias that affects nearly all previous measurements of divalent mercury. The dual-channel continuous mercury measurement system developed, tested, and previously deployed by this research group can make divalent mercury measurements without this low bias. The work has three specific aims: (1) to conduct a year-long measurement campaign of elemental and divalent mercury, related oxidants, and other chemical and meteorological variables; (2) use the zero-dimensional F0AM model to identify which mercury chemical mechanisms and reaction rates minimize model-measurement discrepancies; and (3) update GEOS-Chem’s mercury oxidation mechanism with the F0AM parameters to minimize GEOS-Chem model-measurement discrepancies. Results from this work will enhance our understanding of mercury chemistry and chemical species affected by mercury chemistry, including halogens, ozone, and nitrogen oxides.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目的跨机构合作研究人员将通过定量测量二价汞化合物（排放到大气中的汞更易溶于水的形式），提供大气中汞氧化相关化合物的新综合数据集。在元素状态下，它与大气中的氧化剂发生各种反应，形成二价形式，但对于哪些氧化剂种类以及这些反应发生的速率存在许多不确定性。该项目的主要目标是。两名研究生将使用这些新的形态汞测量值以及之前的测量值来定量表征盐湖城地区镁矿开采设施附近的汞形态和采样羽流的自由基预算。在该项目过程中接受了培训，项目团队计划向政策制定者提供有关汞化学及其对人类健康影响的最新信息，该团队还计划与州监管机构合作，以潜在地扩大汞化学的社会效益。最近一项有关标准测量技术的发现揭示了一种系统性低偏差，该偏差几乎影响了之前所有的二价汞测量。该研究小组开发、测试和先前部署的双通道连续汞测量系统可以产生二价汞。这项工作有三个具体目标：(1) 对元素汞、二价汞、相关氧化剂以及其他化学和气象变量进行为期一年的测量活动；零维 F0AM 模型，以确定哪些汞化学机制和反应速率可最大限度地减少模型测量差异；(3) 使用 F0AM 参数更新 GEOS-Chem 的汞氧化机制，以最大限度地减少 GEOS-Chem 模型测量结果的差异。增强我们对汞化学和受汞化学影响的化学物质（包括卤素、臭氧和氮氧化物）的了解。该奖项反映了通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。