RUI Ramifications of Ethanol Usage as a Biofuel: Quantifying Sources and Impacts on the Light Absorbing Properties of Rainwater

该项目旨在调查乙醇的大气化学，以及以其作为汽油燃料添加剂的使用为中心的乙醇产量增加的影响。有色溶解有机物(CDOM)是影响雨水中乙醇浓度的另一个潜在环境来源。初步数据表明，雨水在模拟阳光下暴露很短(~4小时)后，可以通过光解产生乙醇。这些RUI(本科生研究所)PI指数此前已经表明，在北卡罗来纳州威尔明顿和巴西圣保罗采集的降水样本中，存在可测量的乙醇浓度差异。在不同的降雨事件中，雨水中乙醇的浓度差异很大，更高的浓度出现在与大陆气团有关的风暴期间。降水中高浓度的乙醇被认为会影响大气的氧化能力，并可能对太阳辐射传输和气候产生间接影响。该项目试图回答三个相关问题：1)环境雨水中生物燃料和天然衍生乙醇的相对比例是多少？2)光解乙醇对雨水的发色性质有什么影响？3)CDOM丰度和光化学活性变化对乙醇生产的影响是什么反应途径和分子水平的变化？

This project seeks to investigate the atmospheric chemistry of ethanol and the impacts of increasing levels ethanol production centered on its use as a gasoline fuel additive. Colored dissolved organic matter (CDOM) is another potential environmental source having impact on the concentration of ethanol in rainwater. Preliminary data suggests that ethanol can be produced by photolysis of rainwater after short (~4 hour) exposure to simulated sunlight. These RUI (Research at Undergraduate Institution) PIs have previously shown that there is a measurable concentration difference of ethanol in precipitation samples collected in sites from Wilmington NC and in Sao Paulo Brazil. The concentrations of ethanol in rainwater vary significantly between rain events, with higher concentrations occurring during storms associated with continental air masses. High concentrations of ethanol in precipitation are said to influence the oxidizing capacity of the atmosphere and may have indirect effects on solar radiative transfer and climate.The project seeks to answer three related questions: 1)What are the relative proportions of biofuel and naturally derived ethanol in ambient rainwater? 2)What are the impacts of photolysed ethanol on the chromophoric properties of rainwater? 3) What are the reaction pathways and molecular level compositional changes responsible for changes in CDOM abundance and photochemical lability upon ethanol production?