United States Air and Radiation EPA420-F-01-019
Environmental Protection June 2001
Agency
Office of Transportation and Air Quality
&EPA Regulatory
Announcement
Adjustment to Reformulated
Gasoline VOC Standard
The U.S. Environmental Protection Agency (EPA) is finalizing a
rulemaking that will make it easier for oil refiners to use ethanol in
cleaner-burning gasoline supplied to the Chicago and Milwaukee areas,
while continuing to achieve ground-level ozone benefits similar to those
in the Reformulated Gasoline (RFG) program. The rule helps provide
maximum flexibility for refiners and helps reduce costs for blending
ethanol into gasoline by adjusting the volatile organic compounds
(VOC) standards for ethanol reformulated gasoline. This final rule
recognizes the environmental benefits of ethanol and ensures that it will
continue to play a significant role in the cleaner-burning RFG program.
Overview
The final rule is specific to Chicago and Milwaukee because they are the
only areas of the country that use ethanol exclusively in RFG. Increased
VOC emissions can occur from combining RFG made with the oxygen-
ate methyl tertiary butyl ether (MTBE) and RFG made with ethanol in
automobile gasoline tanks.
In March of this year, EPA issued an enforcement discretion for these
areas, allowing the adjustment to take place prior to this rule being made
final. This rule will make it less expensive to blend ethanol into reformu-
lated gasoline, which should also help boost supply. Chicago and Milwau-
kee saw gasoline prices over $2.75 per gallon in the summer of 2000. This
year, prices in Chicago and Milwaukee have not been as high - $2.08 per
gallon.
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Background
This final rule increases the flexibility available to refiners to formulate
RFG with ethanol by adjusting the VOC performance standard under
Phase II of the RFG program for blends that contain 10 volume percent
ethanol. The VOC performance standard will be 2 percentage points less
stringent for ethanol use at 3.5 weight percent oxygen. With the adjust-
ment, fuel providers would be able to blend 10 volume percent ethanol
into RFG blendstock that has a slightly higher evaporation rate than
blendstock used for MTBE or any other oxygenate. This higher evapora-
tion rate is equivalent to an increase in the Reid Vapor Pressure (RVP) of
the gasoline by 0.3 pounds per square inch (psi). Thus, the proposed
VOC adjustment will reduce the cost of blending 10 volume percent
ethanol into RFG blendstock, making ethanol use more cost-effective.
In June 2000, EPA proposed an adjustment equivalent to an increase in
RVP of about 0.2 psi. In response, the Illinois EPA submitted a study
which recommended an adjustment equivalent to 0.5 psi. An adjustment
of 0.5 psi would negate a large portion of the air quality benefits of Phase
II RFG. Using the results of EPA's ozone modeling, and additional
information on the effects of oxygenates on motor vehicle emissions,
EPA determined that an adjustment of 0.3 psi may be more appropriate to
account for the additional carbon monoxide (CO) reductions from etha-
nol blended RFG.
EPA is allowing the adjustment because RFG with 10 volume percent
ethanol results in a reduction in emissions of CO. The reduction in CO
allows a slight increase in VOC emissions. Therefore, the emissions
performance standard for VOCs can be adjusted without affecting the
program's smog reduction benefits.
This rule implements the recommendation of the National Research
Council that EPA recognize the contribution of CO to smog formation in
evaluating the benefits of RFG. It also takes into account an ozone study
conducted by the Illinois Environmental Protection Agency that illus-
trated that increases in emissions of VOCs could be offset by decreases in
CO.
Using the results of the Illinois and Wisconsin ozone modeling and
additional information on the effects of oxygenates on motor vehicle
emissions, EPA determined that an adjustment equivalent to an increase
in RVP of 0.3 psi is appropriate to account for the additional CO reduc-
tions from ethanol-blended RFG. When added to gasoline, ethanol
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increases the evaporation rate, causing more VOC emissions, but ethanol
helps to reduce CO emissions. Both pollutants play a role in ozone
(smog) formation. So while there will be an increase in VOCs, they will
be offset by the concurrent CO reductions. Air quality will not be com-
promised by this change.
The Clean Air Act requires that RFG contain 2.0 weight percent oxygen.
To meet this requirement, oil refiners generally choose between MTBE
and ethanol. If gasoline containing MTBE leaks or is spilled into the
environment, it can enter groundwater and make water supplies undrink-
able due to taste and odor impacts. EPA called on Congress last year to
pass legislation that will significantly reduce or eliminate the use of
MTBE. By providing refiners with more flexibility to use ethanol, this
proposal will help reduce the use of MTBE.
Of RFG
About 75 million people are breathing cleaner air because of RFG. The
cleaner-burning RFG program significantly reduces air pollution in the
smoggiest cities in the U.S. RFG reduces smog-forming pollutants by
105,000 and toxic pollutants by 24,000 tons annually. This is equivalent
to eliminating the pollution from 16 million cars.
For
You can access documents on RFG electronically on the Office of
Transportation and Air Quality (OTAQ) Web site at:
http ://www. epa. gov/otaq/rfg. htm
For further information on this final rule, please contact Barry Garelick
at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality (6406J)
1200 Pennsylvania Avenue NW
Washington, DC 20460
(202) 564-9028
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