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

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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?