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

Syracuse University, Syracuse NY

Investigators

Abstract

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 effects of 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).