By Luke Valin
Windsor Heights, Iowa
Chemistry
When beginning my summer research back in 2003, I had no idea how computers could be used to understand chemistry and air pollution. Now I have come to see the power of computational research in understanding atmospheric chemistry.
I'm using the skills that I have gained in the classroom to improve our knowledge of the atmosphere.'
—Luke Valin |
I started by learning that the most important oxidant in the atmosphere is the hydroxyl radical. It destroys organic pollutants such as methane and hydrogenated chlorofluorocarbons (CFCs), which are closely related to the CFCs that we recognize as responsible for creating the ozone hole. Hydroxyl radical reacts to form acid rain. Since high concentrations lead to acid rain and low concentrations lead to the buildup of pollutants, we want to understand what affects the concentration of hydroxyl radical so that air pollution and acid rain can effectively be avoided.
Research has shown that hydroxyl radical is produced when ozone is hit by sunlight, which is easy to model, but we also know that there is some other significant source that does not need sunlight and is difficult to model. Scientists have discovered that alkenes, a family of chemicals, react with ozone to form hydroxyl radical at widely varying levels, depending on the alkene. This is where my research becomes important.
Isoprene, the most abundant alkene in the atmosphere, is naturally released by plants and forms hydroxyl radical when reacted with ozone like other alkenes. But hydroxyl radical’s extreme reactivity creates a problem for experiments; even modern technology cannot effectively measure its concentration in situ. Stepping in with the aid of computers, we theoreticians make use of intense physics to make predictions of hydroxyl radical yield from the ozone-isoprene reaction.
We can compare the quality of our methods with the quality of experimental methods and identify which ones need improvement. Computers are also useful in describing the reaction mechanism that leads to hydroxyl formation, which leads to better understanding and improves the efficiency of future research.
If it sounds complicated, it is. My understanding of this research has grown immensely over the past two years as my adviser, Professor Keith Kuwata, has enlightened me time after time. My work on this project with Professor Kuwata has been invaluable and has given me a sense of satisfaction. I am using the skills that I have gained in the classroom to improve our knowledge of the atmosphere.
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