DETERMINING AIR QUALITY PLUME OVER NEAR-SHORE LAKE MICHIGAN

Several communities surrounding Lake Michigan have been labeled as excess ozone zones including Kenosha, Wisconsin, where air quality violates the 8-hour ozone standard. This is problematic as excess ozone is harmful to vegetation and can cause asthma, respiratory problems, and cardiopulmonary problems in humans. Along with high ozone levels, additional pollutants are being introduced to the atmosphere due to the development of near-by power plants and industrial processes. When determining air quality in communities surrounding Lake Michigan, it is important to understand the unique atmospheric processes occurring between air plumes over an urban/rural air-shed and a large adjacent freshwater lake. For this study, concentrations of nitrogen dioxide, ozone, formaldehyde, and sulfate were measured by the method of Differential Optical Adsorption Spectroscopy (DOAS) from June 11 to November 6, 2009. The DOAS instrument used measures concentrations of atmospheric gases by means of the Beer-Lambert principle. From this study, it was determined that daytime air flow occurred mainly from east to west, whereas the opposite was true during the night. Air from the east had higher concentrations of sulfate and ozone while air from the west had higher formaldehyde and nitrogen dioxide levels. These findings are due to a combination of atmospheric lifetimes, ozone formation reactions, and the unique ozone retention plume created over Lake Michigan. In addition, an odd oxygen relationship between onshore and offshore air flow was noted and rapid changes in wind direction were analyzed in regards to rapid changes in ozone levels.