California Air Resources Board

Background

California’s Health and Safety Code (HSC 43830.8) requires that a multimedia evaluation (MME) be conducted and reviewed by the California Environmental Policy Council (CEPC) before specifications for new motor vehicle fuels can be adopted by the California Air Resources Board (CARB). The purpose of the MME is to develop information that will enable the CEPC to determine whether a new fuel specification would cause any significant adverse impacts to public health or the environment. 

Ethanol is a renewable fuel with lower carbon intensity than petroleum-derived gasoline. California gasoline is currently blended with up to 10 percent ethanol by volume (E10), the maximum ethanol content allowed by the California Reformulated Gasoline (CaRFG3) Regulations. CARB has initiated an MME to understand any potential environmental or public health impacts from the use of 15 percent ethanol by volume (E15) in California. The risk posed by E15 in gasoline is assessed as a relative risk compared to E10 in California gasoline currently in use.

California Multimedia Evaluation of E10-E15 Gasoline-Ethanol Blends Tier II Report

Tier II is the second step in the three-tier MME process. The Tier II Report presents the testing procedures and results that addressed the data gaps identified during Tier I.  

Comparison of Exhaust Emissions Between E10 CaRFG and Splash Blended E15

As a part of the MME for E15, CARB contracted with the University of California at Riverside (UCR) Bourns College of Engineering – Center for Environmental Research and Technology (CE-CERT) to evaluate exhaust emissions from the use of CaRFG containing 15 volume percent ethanol. This study looks at the effects of increased ethanol content on exhaust emissions in 20 vehicles, all model year 2016 or newer and equipped with three-way catalysts. Measured emissions include: oxides of nitrogen; total hydrocarbons; non-methane hydrocarbon; carbon monoxide; carbon dioxide; particulate matter mass; particulate number; 1,3-butadiene, benzene, toluene, ethylbenzene, xylene isomers, ethanol, and carbonyl compounds. 

California Multimedia Evaluation of E11-E15 Gasoline-Ethanol Blends Tier I Report

The Tier I report is the first step in a three-tier process evaluating the cumulative health and ecological impacts from releases to air, surface water, groundwater and soil at all stages of the ethanol life cycle: production; storage and distribution; and use. 

back to Fuels Multimedia Evaluation program