The U.S. EPA Motor Vehicle Emission Simulator (MOVES) 3.0 model has been used to estimate the impact on air emissions from on-road gasoline/ethanol-powered vehicles if the 1-psi Reid vapor pressure (RVP) waiver for 10% ethanol blends were to be eliminated. The model was run for the years 2025 and 2030 in the state of Missouri to determine the percentage change in emissions due to the removal of the waiver. Missouri was chosen as a representative state because it has both rural and urban areas, temperatures in the mid-range of those in the United States as well as mostly urban areas that have required reformulated gasoline (RFG) and significant parts of the state that have no RFG requirements. The percentage change calculated for Missouri was adjusted for the entire United States proportionally by the amount of fuel affected by the change, and then applied to the total national on-road gasoline/ethanol emissions as estimated by the EPA.
The impact of the removal of the waiver would be beneficial to air quality, as emissions of carbon monoxide (CO), oxides of nitrogen (NOx) and volatile organic compounds (VOCs) would be reduced. In addition, if the elimination of the 1-psi waiver leads to the replacement of E10 with E15, it will also decrease greenhouse gases and particulate emissions.
The results showed that eliminating the 1-psi RVP waiver for E10 would result in reductions of CO, NOx, and VOC emissions from the on-road light-duty vehicle fleet. As these pollutants are known precursors to ozone formation, eliminating the 1-psi RVP waiver for E10 would result in improved air quality and reduced ozone. By facilitating greater consumption of E15, the removal of the 1-psi waiver for E10 would also reduce lifecycle GHG emissions.