Regulation of Fuels and Fuel Additives: Renewable Fuel Standard ...

RFG due to the absence of an RVP waiver for ethanol blends. The reader is referred to
Chapter 2 of the DRIA for discussion of how ethanol levels will change at the state-level.
Table VIII.B.3-2 presents the percentage change in VOC and NOx emission
inventories under our sensitivity case (i.e., when we apply the emission effects of the
EPA Predictive Models to all motor vehicles).
Table VIII.B.3-2
Change in Emissions from Gasoline Vehicles and Equipment in Counties Where Ethanol
Use Changed Significantly – Sensitivity Analysis
7.2 Bgal Min 7.2 Bgal Max 9.6 Bgal Min 9.6 Bgal Max
RFG Areas
Ethanol Use Down Up Down Up
VOC 2.6% 0.2% 2.6% 0.2%
NOx -9.0% 4.7% -9.0% 4.7%
Low RVP Areas
Ethanol Use Up Up Up Up
VOC 2.1% 2.1% 3.1% 2.5%
NOx 8.2% 10.6% 9.8% 8.9%
Other Areas
Ethanol Use Up Up Up Up
VOC 3.4% 3.4% 4.6% 3.7%
NOx 8.4% 10.1% 10.3% 8.8%
Directionally, the changes in VOC and NOx emissions in the various areas are
consistent with those from our primary analysis. The main difference is that the increases
in VOC emissions are smaller, due to more vehicles experiencing a reduction in exhaust
VOC emissions, and the increases in NOx emissions are larger.
C. Impact on Air Quality
We estimate the impact of increased ethanol use on the ambient concentrations of
two pollutants: ozone and PM. Quantitative estimates are made for ozone, while only
qualitative estimates can be made currently for ambient PM. These impacts are described
below.
1. Impact of 7.2 Billion Gallon Ethanol Use on Ozone
We use a metamodeling tool developed at EPA, the ozone response surface
metamodel (Ozone RSM), to estimate the effects of the projected changes in emissions
from gasoline vehicles and equipment for the 7.2 billion gallon ethanol use case. The
changes in diesel emissions are negligible in comparison. We did not include the
estimated changes in emissions from renewable fuel production and distribution, because
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