RUI: Impact of Changing Fuel Usage on the Atmospheric Cycling of Ethanol, Optically Active Organic Compounds and Iron (Fe) in Rainwater

RUI：改变燃料使用对雨水中乙醇、光学活性有机化合物和铁 (Fe) 的大气循环的影响

• 批准号: 1003078
• 负责人: Robert Kieber
• 金额: $ 62.24万
• 依托单位: University of North Carolina at Wilmington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1003078&HistoricalAwards=false
• 关键词: RUI; Impact; Changing; Fuel; Usage

The overarching goal of the research is to delineate potential impacts of current and future fossil fuel usage and emission changes on the chemistry of the troposphere. The first objective explores the link between increased ethanol production and use to possible increased levels of ethanol and volatile organic carbon compounds in precipitation. The first detailed seasonal and temporal profile of ethanol concentrations in rainwater will be developed with an emphasis on the influence of air mass origin on concentrations. Rainwater will be collected in Wilmington, NC and in São Paolo, Brazil where ethanol makes up 40% of vehicle fuel. This comparison will provide a unique and novel opportunity to examine how shifting ethanol usage in North America could ultimately impact the chemistry of the troposphere. The second objective examines how fossil fuel emissions from various combustion sources including 85% ethanol vehicle fuel (E85), gasoline and diesel fuels as well as coal and fuel oil combustion impact the abundance of light absorbing or chromophoric dissolved organic material (CDOM) in rainwater. Specific questions to be addressed involve determining the chemical composition of CDOM produced from various fuel sources initially and as a function of irradiation time in comparison to changes observed in analogous rainwater samples. The final objective of the research explores the relationship between fossil fuel emissions and the speciation of iron in atmospheric waters. Preliminary evidence suggests the chromophoric material in rainwater contains ligand(s) of fossil fuel origin that stabilize Fe(II) allowing significant concentrations to occur in precipitation even in the presence of micromolar concentrations of the oxidant hydrogen peroxide. Recent data suggest that the abundance of these ligands is changing over time in rainwater although it is unclear why. This phase of the research will determine if DOM obtained from various fuel sources is capable of binding Fe(II) and Fe(III) and whether the abundance of these ligands is changing.Exploring the importance of shifting fuel usage on the composition of the troposphere is central to the understanding of a host of current as well as future atmospheric processes as the quantity and quality of fuel used in energy production changes. Results of this research will have important implications for global climate change because chromophoric material directly influences the spectral attenuation of sunlight reaching the earth's surface. An additional consequence of the production of chromophoric material in rainwater from combustion sources is the potential impact on the oxidizing capacity of the troposphere by generating significant quantities of aqueous phase hydrogen peroxide. Addressing the redox chemistry of iron is important because any change in iron speciation affects the lifetime and bioavailability of iron as a nutrient, which in turn will alter the rate of marine primary productivity. Marine primary productivity is known to play a significant role in removal of carbon dioxide from the atmosphere and hence impacts the magnitude of global warming. The project will support a post-doctoral researcher, two master's level graduate students, three undergraduates and one high school student per year. Young students are attracted to this type of study because they perform high profile environmental research of international interest. This ultimately motivates them to continue their education and choose a career in science which enhances the recruiting and retaining of young students in critical STEM fields.

该研究的总体目标是描述当前和未来的化石燃料使用情况以及对对流层化学反应的潜在影响。第一个目标探讨了增加乙醇的产生与可能增加的乙醇水平和挥发性有机碳化合物之间的联系。将开发乙醇浓度的第一个详细的季节性和临时概况，以重点是空气质量起源对浓度的影响。雨水将在北卡罗来纳州的威尔明顿和巴西的圣保罗收集，乙醇占汽车燃料的40％。这种比较将提供一个独特而新颖的机会，以研究北美转移的乙醇使用方式最终如何影响对流层的化学反应。第二个客观检查如何从各种组合来源的化石燃料排放量，包括85％乙醇燃料（E85），汽油和柴油燃料以及煤炭和燃油组合影响雨水吸收或彩色溶解有机材料（CDOM）的抽象。要解决的具体问题涉及确定最初从各种燃料来源产生的CDON的化学组成，并且是辐射时间的函数，而不是在类似的雨水样品中观察到的变化。该研究的最终目标探讨了化石燃料排放与大气水中铁的规格之间的关系。初步证据表明，雨水中的发色材料含有化石燃料起源的配体，这些配体稳定Fe（II），即使在存在微摩尔浓度的过氧化氧化物的存在下，也允许在降水中发生显着浓度。最近的数据表明，这些配体的抽象在雨水中随着时间的流逝而变化，尽管目前尚不清楚为什么。研究的这一阶段将确定从各种燃料来源获得的DOM是否能够结合Fe（II）和Fe（III），以及这些配体的丰度是否正在发生变化。探索将燃料使用对对流层的组成的重要性是对当前大量和燃料生产量的宿主以及未来大气质量的理解以及燃料生产的量的理解。这项研究的结果将对全球气候变化具有重要意义，因为发色材料直接影响到达地球表面的阳光的光谱衰减。通过混合物来源在雨水中生产发色材料的另一个后果是通过产生大量大量的过氧化水氢氧化物对对流层的氧化能力的潜在影响。解决铁的氧化还原化学很重要，因为铁规格的任何变化都会影响铁作为营养素的生命和生物利用度，从而改变海洋初级生产率的速度。众所周知，海洋初级生产力在从大气中去除二氧化碳中起着重要作用，因此影响了全球变暖的幅度。该项目将支持一名博士后研究人员，两名硕士学位的研究生，三名本科生和一名高中生。年轻学生被这种研究所吸引，因为他们对国际兴趣进行了备受瞩目的环境研究。这最终激发了他们继续教育，并选择科学职业，从而增强了在关键STEM领域的年轻学生的招聘和保留。