CAREER: Photochemistry at "Dirty" Ice Surfaces: Effects of Solutes on Reactivity

化学系环境化学科学项目将资助锡拉丘兹大学的Tara Kahan教授研究环境溶质对“脏”冰表面化学反应的影响，即包括常见环境溶质的表面。该项目的重点是将冰表面的物理性质与表面反应动力学联系起来。研究了在存在和不存在卤化物盐和有机物等常见环境溶质的情况下，冰面上的表面性质和反应动力学。这项研究的结果被用来预测冰雪表面发生的化学物质对城市和偏远地区空气和水质量的影响。卡汉教授正在开发一个暑期工作坊，教中学生如何成为“科学记者”。研讨会参与者采访了大气和环境科学家，并在锡拉丘兹的米尔顿·J·鲁宾斯坦科学和技术博物馆展示了基于这些采访的最终项目。这项工作的更广泛的科学影响包括改进对白雪覆盖地区空气和水质量的预测，以及提高中学生的科学素养和参与度。Kahan和她的同事已经证明，常见的环境溶质可以极大地改变冰表面污染物的命运，但溶质对冰化学的影响在很大程度上仍未被探索。卡汉研究小组计划调查冰成分对光化学动力学和机理的影响。预计这些研究将提高预测冰雪中光化学对大气成分、污染物去向和气候的影响的能力。具体目标是确定(I)卤化物和有机物(OM)等常见溶质如何在冰表面分布(荧光和拉曼显微镜)，(Ii)常见溶质如何影响冰表面有机污染物的光解动力学和产物(荧光光谱和气相色谱-质谱仪)，以及(Iii)常见溶质如何影响冰表面羟基自由基(OH)的光化学产生和归宿(层析、荧光光谱和激光诱导荧光)。

With this CAREER award, the Environmental Chemical Sciences Program of the Division of Chemistry is funding Professor Tara Kahan of Syracuse University to investigate the effects of environmental solutes on chemical reactivity at "dirty" ice surfaces; i.e. surfaces which include common environmental solutes. The project focuses on relating physical properties of ice surfaces to surface reaction kinetics. Surface properties and reaction kinetics at ice surfaces are investigated in the presence and absence of common environmental solutes such as halide salts and organic matter. The results of this research are used to predict the impact of chemistry occurring at snow and ice surfaces on air and water quality in cities and in remote regions. A summer workshop being developed by Professor Kahan teaches middle-school children to be 'science journalists.' Workshop participants interview atmospheric and environmental scientists, and display final projects based on these interviews at the Milton J. Rubenstein Museum of Science and Technology in Syracuse. The broader scientific impacts of this work include improved predictions of air and water quality in snow-covered regions, and improved scientific literacy and engagement in middle-school children.Dr. Kahan and her coworkers have shown that common environmental solutes can greatly alter the fate of pollutants at ice surfaces, but the effects of solutes on ice chemistry remain largely unexplored. The Kahan research team plans to investigate the effects of ice composition on photochemical kinetics and mechanisms. It is envisioned that these studies will improve the ability to predict the effectsof photochemistry in snow and ice on atmospheric composition, pollutant fate, and climate. The specific objectives are to determine (i) how common solutes such as halides and organic matter (OM) are distributed at ice surfaces (fluorescence and Raman microscopy), (ii) how common solutes affect the photolysis kinetics and products of organic pollutants at ice surfaces (fluorescence spectroscopy and gas chromatography-mass spectrometry) and (iii) how common solutes affect the photochemical production and fate of hydroxyl radicals (OH)at ice surfaces (chromatography, fluorescence spectroscopy, and laser-induced fluorescence).