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David De Haan
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Project title: Direct Analysis of Reactions Between Glyoxal, Methylglyoxal, Amino Acids and Glycerol During Cloud Processing.David De Haan is feeling a little déjà vu, back at CU 15 years after earning his doctorate in John Birks’ research group. Today, DeHaan is working as a Visiting Fellow with CIRES Fellow Maggie Tolbert on the chemistry of aldehyde uptake by aerosol–and his lab experiments are set up in space formerly occupied by the Birks group. “One day in 1990, John walked into the lab and proposed conducting some flow tube experiments on the chemistry of chlorine peroxide, a chemical involved in chlorine-catalyzed stratospheric ozone depletion, on ice surfaces,” De Haan said. “I’ve been happily working on aerosol chemistry ever since.” A native of Los Angeles’ smoggy inland valleys, De Haan soon became involved in the chemistry of smog haze. “Although ground-level ozone levels in L.A. are much better–lower–than they used to be when I was growing up, visibility hasn’t improved at all,” he says. “The fact that there are still so many aerosol particles blocking our view means that we don’t fully understand how those particles form, and so regulations can’t be effective.” At CIRES, De Haan is unraveling the mechanisms of aerosol formation via cloud and fog droplets. Highly water-soluble gases like glyoxal and methylglyoxal dissolve into water droplets, but when those droplets evaporate, these compounds begin to polymerize rather than evaporate. In the presence of amine compounds, light-absorbing brown polymers form. “Scientists have found brown, nitrogen-containing polymers in atmospheric aerosol,” De Haan explained. “This could be where they’re coming from.” Until a few years ago, it was thought that glyoxal and methylglyoxal could not form aerosol. Now, they look like major sources. In urban areas, glyoxal and methylglyoxal are mainly produced by atmospheric oxidation of the aromatic components in gasoline. “It’s possible that replacing these components with ethanol will finally clear the air,” De Haan said. De Haan is an Associate Professor of Chemistry at the University of San Diego, where he teaches technology-rich courses in analytical and environmental chemistry and leads a research group made up entirely of undergraduate students. During 2008-2009, four USD students will participate in summer research at CIRES. “Early research experiences are what draw people to careers in science,”De Haan said. “That’s how I got pulled in.” Office: CIRES 152 |
