Collaborative Research: Mercury in the Atmosphere Over the Eastern United States

该项目包括在北美上空进行的第一次以汞为重点的大规模空中实验。该项目有两个主要目标：1)限制美国东部主要来源地区的汞排放；2)量化对流层下层汞的分布和化学转化。为了实现这些目标，NSF/国家大气研究中心C-130飞机将配备一套最先进的仪器来测量气态元素汞（GEM）、气态氧化汞（GOM）、颗粒结合汞（pHg）和一套其他化合物，用于空气质量表征。飞行计划将用于研究俄亥俄河谷的工业汞源，北美向大西洋的汞流出，以及对流降水对美国东南部表面湿态汞沉积的影响。操作计划将利用区域和全球预测模型来优化飞行时间的使用。C-130的观测结果将在任务结束后用几种化学传输和拉格朗日模型进行整合和分析。这些模型将用于检查观测与排放清单之间的一致性，允许在统一框架内将地面观测与飞机观测结合起来，约束源-受体关系，并检验关于汞的化学转化和全球循环的不同假设。人类接触汞是一个重大的健康风险，也是一个具有国家和全球意义的问题。项目结果将减少有关源-受体关系的不确定性，以及国内、国外和自然来源对美国东部大气汞库存的相对贡献。该研究将涉及来自美国几个不同机构的研究生和本科生，因此将使这些学生接触到具有重大国家意义的高水平科学问题。除了由美国科学家组成的核心小组外，来自加拿大、意大利、德国和俄罗斯的汞科学家也将参与这项工作，从而加强在全球环境问题上的国际科学合作。

This project comprises the first large-scale airborne experiment focused on mercury over North America. The project has two primary objectives: 1) Constrain emissions of mercury from major source regions in the eastern United States, 2) Quantify the distribution and chemical transformations of mercury in the lower troposphere. To address these goals the NSF/National Center for Atmsopheric Research C-130 aircraft will be equipped with a suite of state-of-the-art instrumentation to measure gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), particle-bound Hg (pHg) and a suite of other compounds for air mass characterization. Flight plans will be designed to study industrial mercury sources over the Ohio River Valley, outflow of North American mercury to the Atlantic, and the impact of convective precipitation on surface wet deposition of mercury over the Southeast U.S. Operational planning will utilize regional and global forecast models to optimize the use of flight time. The C-130 observations will be integrated and analyzed after the mission with several chemical transport and Lagrangian models. These models will be used to examine the consistency between observations and emission inventories, allow the integration of ground-based observations with aircraft observations in a unified framework, constrain source-receptor relationships, and test different hypotheses about the chemical transformations and global cycling of mercury.Human exposure to mercury is a significant health risk and a problem of national and global significance. Project results will reduce the uncertainties concerning source-receptor relationships and the relative contributions of domestic, foreign and natural sources to the inventory of atmospheric mercury over the eastern U.S. The research will involve a number of graduate and undergraduate students from several different U.S. institutions and thus will expose these students to working on high-level scientific problems of great national significance. In addition to a core group of scientists from the U.S., mercury scientists from Canada, Italy, Germany and Russia will also collaborate in the work, thus strengthening international scientific cooperation on global environmental problems.