Do EPA Tier II-compliant diesel engines reduce lobstermen's diesel exhaust exposure?

Diesel exhaust (DE) is an occupational exposure with health effects that include headaches, nausea, cancer and respiratory disease. Funded by the Harvard ERC, this study compares exposures of lobstermen before and after replacement of old diesel engines with new EPA Tier II diesel engines installed on 19 lobster boats. [U.S. EPA Region I provided a grant to the Maine Marine Trades Association in partnership with the Maine Department of Environmental Protection for the marine engine replacement program.] Data were collected during lobster fishing activities between July 2009 and June 2010 to test the hypothesis that the Tier II engines result in less DE exposure. Real-time sampling instruments were used according to standard protocols. Particle collectors with a 2.5 µm cutoff were used with a personal sampling pump to collect airborne mass on teflon filters to determine the concentration of PM_2.5. Collectors with a 1.0 µm cutoff were used with a glass fiber filter to measure elemental and organic carbon content of PM. Preliminary analysis of the pre-engine exchange data showed PM_2.5 exposures ranging from 9-104 µg/m³ with an average of 48 µg/m³ across 19 boats. Post-engine exchange data will be collected in May/June 2010. Exposure levels for elemental carbon (a marker for DE) will be compared with EPA and NIOSH standards.