Great Lakes Marine Air Emissions—We’re Different Up Here!

Abstract

This paper presents a bottom-up air emission inventory (AEI) for two ports on the Great Lakes. The details of every commercial vessel—US, Canadian, and Foreign Flag—and every visit to each port were cataloged for 2004. The actual open-lake speed, reduced speed to enter the port, the time to maneuver from the breakwall to the dock, and the times at the dock performing cargo operations were evaluated. Appropriate current emission factors for the type of propulsion engine and auxiliary engines for each vessel were used for the times in each mode to obtain total emissions. The Port of Cleveland, Ohio, is particularly important because that port was studied as part of the EPA's National Emission Inventory in 1999 and 2002, and those results were used as the marine transportation mode emissions baseline that is extrapolated to all other Great Lakes port states, cities, and counties based on port tonnages. The Port of Duluth, Minnesota, was chosen because it is primarily a shipping port as contrasted to Cleveland, which is primarily a receiving port. Vessel operations are quite different in each port. Using this detailed study and current emission factors, Great Lakes marine mode emissions are shown to be about one-half of original study estimates for Cleveland. The relative efficiency of the marine mode of transportation is reviewed for the Port of Cleveland. The Great Lakes vessels, ports, and trade patterns clearly show "We're different up here."