Chemical Processes in the Atmosphere

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The research we perform is in the field of atmospheric chemistry. Our objectives are to further our understanding of chemical processes that occur in the troposphere, the lower layer of the atmosphere where we live and breathe. We study chemical processes in the troposphere that allow us to better understand how things that are emitted are transformed, how quickly, how the transformation takes place, the intermediates that are produced, and where the products of those transformations end up. Our particular focus is on nitrogen species and radical reactions at night and in the early morning. Radicals are small molecules that have an odd number of electrons that are particularly reactive and well suited to initiating chemical reactions. Examples of radicals include the nitrate radical (NO3), chlorine atoms (Cl), and the hydroxyl radical (OH). In the next five years, we propose to do many things. We will study changes in the chemical composition of the atmosphere vertically from the ground up, using multiple remote sensing techniques. This is important since we expect that the chemical processes that are occurring just a short distance above our heads at night, are very different that what is occurring at ground level. Since the air eventually all mixes in the morning, it is important that we know what is occurring up there the night before. In the laboratory, we will also study the formation of organic aerosols through the reaction of chlorine atoms with organic pollutants in air. We suspect that this process may be occurring above our heads in the early morning and may contribute to winter smog episodes. And we will study the nighttime formation of another species of interest to us called nitrous acid (HONO). This particular species is formed on surfaces by a complicated mechanism, and is important as a source of radicals the next day. The students that perform this research are well trained in using sophisticated instrumental methods, advanced mathematical methods, in communication skills, and in critical thinking. They are the scientists and policy makers of tomorrow.