The increased use of renewable fuels will also impact emissions with some emissions such as hydrocarbons, nitrogen oxides (NOx), acetaldehyde and ethanol expected to increase and others such as carbon monoxide (CO) and benzene expected to decrease. However, the impacts of these emissions on criteria air pollutants are highly variable from region to region. Overall the emission changes are projected to lead to increases in population-weighted annual average ambient PM and ozone concentrations, which in turn are anticipated to lead to up to 245 cases of adult premature mortality.NOx is one of the components of smog and EPA clearly states that there will be an increase in emissions of the gas via use of ethanol. In contrast, EPA is proposing to reconsider the ozone standards that were set at 0.075 ppm in 2008 and to set a new “primary” standard at a level between 0.060 and 0.070 parts per million measured over eight hours. We are concerned that the RFS2 could be an impediment to meeting the December 2013 EPA deadline for State Implementation Plans to outline how states will reduce smog to meet the standards. We are further concerned about the 2014 to 2031 deadlines for States to meet the primary standard (deadlines depending on the severity of the problem).
We understand that some areas and states are already using 10% ethanol blends, but we are still concerned that NOx emissions could increase in areas not currently utilizing the blend and that NOx emissions could be transported to areas already using the blend, thus exacerbating smog in both areas.
* Paul Machiele: Director, Fuels Center, Assessments and Standards Division, OTAQ; Paul Argyropoulos, Senior Policy Advisor, OTAQ