Air Pollution Emissions from Conventional and Alternative Transportation Fuels

Project summary:

This project investigated air pollution emissions from conventional (gasoline) and alternative transportation fuels, with specific emphasis on biofuels aimed at reducing greenhouse gas emissions. Previous work at the University of Minnesota has shown that three general approaches are needed for our state to meet its greenhouse gas emission targets: changes to fuels, changes to vehicles, and changes to land use aimed at reducing vehicle-miles traveled.

This project focused on the first topic: environmental impacts of low-carbon fuels. In previous projects the researchers identified that tailpipe emissions of conventional air pollutants are not well characterized for low-carbon fuels.

Air quality modeling of the air pollution effects of alternative fuels must be supported with data on the tailpipe emissions of those fuels relative to conventional fuels. This study presents a literature review of the tailpipe and evaporative emissions from 85% ethanol (E85), 10% ethanol (E10), and 20% biodiesel (BD20) compared to conventional fuels. It was found that E85 causes both positive and negative changes in emissions relative to gasoline, depending on the pollutant, and the changes in some pollutants have an uncertain sign. E10 and BD20 in general exhibit smaller changes in emissions compared to E85, the impacts of which cannot be fully known without air quality modeling.

These findings will be used for use in future air pollution models.