HR: 0800h
AN: A41A-0018    [Abstracts]
TI: Ionic Composition of Atmospheric Aerosols in Chicago
AU: * Fosco, T
EM: tfosco@luc.edu
AF: Loyola University Chicago, 6525 N. Sheridan, Chicago, IL 60626
AU: Schmeling, M
EM: mschmel@luc.edu
AF: Loyola University Chicago, 6525 N. Sheridan, Chicago, IL 60626
AB: Ions in atmospheric aerosols were investigated in Chicago under various meteorological conditions. Special emphasis was placed on the lake breeze, an event regularly occurring in Chicago, but most pronounced during the summer months. Aerosol samples were collected by filtration at Loyola University Chicago Air Station (LUCAS) during 2002 and 2004. The station is located in close proximity to Lake Michigan and therefore excellently suited to study the influence of the lake breeze on local air pollution. The samples were analyzed for anions and cations, including low molecular weight organic acids, using ion chromatography after validation of collection and analysis method. In addition, reactive trace gases were monitored to determine the oxidation power of the local atmosphere during aerosol collection. Results showed that sulfate, nitrate and ammonium were the most abundant ions in Chicago air. In general, highest ion concentrations were associated with Southwest wind transporting pollution from the city to the station. Ammonium to sulfate ratios were highest during lake breeze events indicating a processed air mass. This was supported by elevated ozone levels. Finally, we could distinguish between three cases where sulfate, nitrate and oxalate concentrations were found dependent of temperature as well as ozone and nitrogen oxide mixing ratios.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting