UC Riverside study shows emissions reductions in E15 use in California

In California, a newly released, peer-reviewed study from the University of California, Riverside, shows that the E15 ethanol blend provides notable emissions reductions compared to California’s regular reformulated gasoline. The Renewable Fuels Association hailed the report as proof of the value of E15 for The Golden State, which has yet to allow the E15 blend to be used.

According to the study, emissions of total hydrocarbons, non-methane hydrocarbons, and carbon monoxide all showed either marginally or statistically significant reductions for E15 compared to regular California gasoline. In addition, particulate matter (PM) and solid particle number emissions dropped substantially with E15, and E15 showed lifecycle greenhouse gas emissions savings when compared to E10. Nitrogen oxide (NOx) emissions when using E15 showed marginal reductions in many cases, but the changes in NOx were not statistically significant.

The research will appear in the October 2023 journal Fuel, and was supported by RFA, the California Air Resources Board and other organizations. Researchers noted that this is the largest U.S. study to date that focuses on the effects of ethanol fuels on tailpipe emissions from current technology vehicles.