Source Apportionment of Dry Deposited and Airborne Coarse Particles Collected in the Chicago Area

Long-term dry deposition and dichotomous coarse particle samples were collected between November 1993 and October 1995 in Chicago, IL, as part of the Lake Michigan Mass Balance Study (LMMBS). In addition, short-term dry deposition and airborne coarse particle (Noll Rotary Impactor) samples were collected during the Atmospheric Exchange Over Lakes and Oceans Study (AEOLOS). These samples were analyzed for trace metals and modeled using the U.S. EPA's Chemical Mass Balance (CMB) Model (Version 7) to determine the sources of these particles. The modeled source contributions were similar. The results indicate that light duty unleaded vehicles, soil dust, and heavy duty diesel vehicles were the major sources of ambient coarse and dry deposited particles in Chicago. The other sources found were lime kilns, coke dust, aluminum foundryreverberatory furnace, coal-fired power plant, paint spray booth, and municipal incineration. The results from this study indicate that the CMB approach can be used to determine the source of deposited particles.