Multivariate statistical techniques were used to investigate source apportionment and source/sink relationships for polycyclic aromatic hydrocarbons (PAHs) in the urban and adjacent coastal atmosphere of Chicago/Lake Michigan in 1994-1995. The PAH signatures for the atmospheric particle phase, surface water particle phase and sediments indicate that atmospheric deposition is the major source of PAHs to the sediments and water column particulate phase of Lake Michigan. The PAH signature for the atmospheric gas phase and water dissolved phase indicate an intimate linkage between the lake and its overlying atmosphere. A modified factor analysis- multiple regression model was successfully applied to the source apportionment of atmospheric PAHs (gas+particle). Coal combustion accounted for 48 ± 5% of the ΣPAH concentration in both the urban and adjacent coastal atmosphere, natural gas combustion accounted for 26 ± 2%, coke ovens accounted for 14 ± 3%, and vehicle emissions (gas+diesel) accounted for 9 ± 4%. Each is an identified source category for the region. These results are consistent with the mix of fossil fuel combustion sources and ratios of indicator PAHs.
Bibliographical noteFunding Information:
The AEOLOS project was funded by the National Exposure Research Laboratory (RTP, NC) of the US Environmental Protection Agency under Cooperative Agreement CR 822046-01 (A. Hoffman, Project Officer). The project received considerable ship-time and logistical support from the Great Lakes National Program of the US EPA in Chicago, IL. Special thanks are extended to A. Bandemehr and P. Horvatin for their support. We acknowledge J. Baker, J. Ondov, J. Offenberg and B. Turpin for many helpful discussions.
- Combustion sources
- Factor analysis
- Lake Michigan
- Multiple regression
- Source apportionment
- Urban atmosphere