Fuel Trends Report:
Gasoline 1995 - 2005
Executive Summary
Compliance and Innovative Strategies Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
&EPA
United States
Environmental Protection
Agency
EPA420-S-08-001
January 2008
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This report presents 1995-2005 clean fuel programs implementation data collected
and analyzed by the Environmental Protection Agency's (EPA's) Office of Transportation and
Air Quality. The data show that significant changes in gasoline composition during this
period resulted in emission reductions often substantially greater than regulatory
requirements. Future reports on fuel trends will be issued periodically.
As a result of the Clean Air Act (CAA) of 1990, EPA adopted clean fuel programs for gasoline. In
1995, EPA implemented the Reformulated Gasoline (RFC) program, designed to reduce emissions of
ozone-causing volatile organic compounds (VOCs) and oxides of nitrogen (NOx), and air toxics such as
benzene and formaldehyde. At the same time, EPA implemented an anti-dumping program, to protect
the emission qualities of conventional gasoline (CG). In 2000, credit for early gasoline sulfur reduction
was provided by EPA's Tier 2 gasoline sulfur program.
These clean fuel programs required gasoline refiners and importers to analyze gasoline, measure
certain emission-related parameters, and submit the data to EPA. These data have limitations, but in
many respects, provide an unparalleled source of information about gasoline property trends since 1995.1
» Gasoline Sulfur Decreases-- Average annual sulfur content in all gasoline dropped from about
300 ppm in 1997 to about 90 ppm in 2005.
» RFC NOx Reductions Exceed Requirements — RFC exceeded applicable NOx performance
standards during both Phase I (1998-1999) and Phase II (2000 and beyond).
» RFC Toxics Reductions Exceed Requirements — On average, Phase I RFC complied with
Phase II standards, and toxic performance still improved with the transition to Phase II
standards.
» Conventional Gasoline NOx and Toxics Emissions Decreased — Between 1998 and 2005,
the summer NOx emissions of conventional gasoline were reduced by 5.7 percent, while summer
exhaust toxics were reduced by 4.7 percent.
« Ethanol Use in RFC Increased and MTBE Use Decreased — In the summer of 1996, about
11 percent of the RFC sold contained ethanol while virtually all the remainder contained MTBE.
By the summer of 2005, the ethanol share increased to about 53 percent, with corresponding
decreases in MTBE.
• - •
As Figure 1 demonstrates, average annual sulfur content in all gasoline dropped from about 300
ppm in 1997 to about 90 ppm in 2005. Early decreases in overall gasoline sulfur content were primarily
due to decreases in RFC sulfur content linked to the phase-in of increasingly stringent RFC NOx emission
performance standards. These NOx emission performance standards did not mandate sulfur reduction,
but lowering sulfur content was one of several property changes important to meeting the RFC NOx
standards. Post-2000 decreases were also due to early Tier 2 sulfur reductions, applicable to both RFC
1 EPA lacks information about certain properties, and has only partial information on others. One important
limitation of the trend analyses in this report is that, with the exception of certain oxygen and oxygenate analyses,
they do not include California gasoline.
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and CG. Phase-in of Tier 2 sulfur reductions began in 2004, but credit generation for early sulfur
reduction was allowed beginning in 2000.
Annual Average Gasoline Sulfur Content- (parts per million)
Estimated from EPA Reporting System Data
350
300 -
250 -
200 -
150 -
100
50
1997 1998 1999 2000 2001 2002 2003 2004 2005
Year
Figure 1
As Figure 2 demonstrates, RFC exceeded applicable NOx performance standards during both
Phase I (1998-1999) and Phase II (2000 and beyond). The summer NOx performance of Phase I RFC
exceeded the standard by as much as 3.5 percent, while the summer NOx performance of Phase II RFC
exceeded the standard by as much as 4.1 percent.
IV
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NOx Performance of Summer RFG-Estimated from EPA Data
(Based on Phase II Complex Model)
| 12
8
re
DI
oj 10 -
8-
2000
2001
2002 2003
Year
2004
2005
"Phase I standard is an
approximation
based on the Phase II
complex model
Figure 2
.-"
RFC also exceeded toxics performance standards. As Figure 3 demonstrates, the summer toxics
performance of Phase I RFC exceeded the standard by as much as 15.1 percent, while the summer toxics
performance of Phase II RFC exceeded the standard by as much as 12.8 percent. Winter RFC toxics
performance also exceeded standards (See Figure 9 in the RFC Trends section). On average, Phase I
RFC complied with Phase II standards, and toxic performance still improved with the transition to Phase
II standards.
Toxics Performance of Summer RFG - Estimated from EPA Data
eline gasoline)
CO CO .&.
o en o
re
ssion Reduction (from
o on o en
1 5
S
o -
(Based on Phase II Complex Model)
s^y
'
1998 1999 2000 2001 2002 2003 2004 2005
— —Reporting Avg.
— ^ Phs II Averaged 3d
Phs I Averaged 3d *
*Phase I standard is an
approximation
Year based on the Phase II
complex model
Figure 3
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As Figures 4 and 5 demonstrate, between 1998 and 2005, the summer NOx emissions of
conventional gasoline were reduced by 5.7 percent, while summer exhaust toxics emissions were reduced
by 4.7 percent. Winter emissions also decreased during this period (See Figures 3 and 5 in the
Conventional Gasoline Trends section). These reductions were not required by EPA regulations; instead,
they were a byproduct of Tier 2 sulfur regulation.
a 1300 -
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1_
S.1280 -
w
2
°>1260
1240 -
1220 -
1200
75
74 -
73 -
g 72 -
M7
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= 69-
68 -
67 -
66
NOx Emissions of Summer CG
Estimated from EPA Reporting System Data
1999 2000
2002 2003
2004 2005
Year
Figure 4
Exhaust Toxics Emissions of Summer CG
Estimated from EPA Reporting System
Year
Figure 5
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The CM required that RFC contain two percent oxygen by weight. MTBE and ethanol were the
primary oxygenates used. Figure 6 shows the increasing use of ethanol in RFC and the decreasing use of
MTBE through 2005. In the summer of 1996, only about 11 percent of the RFC sold contained ethanol
while virtually all the remainder contained MTBE. By the summer of 2005, the ethanol share increased to
about 53 percent, with corresponding decreases in MTBE use.
% of Summer RFC Oxygenated with Ethanol and Ethers (Including Federal RFC Areas in CA)
•Ethanol
BMTBE TAME other
1996
11%
89%
1997
10%
90%
1998
11%
89%
1999
12%
88%
2000
12%
88%
2001
15%
85%
2002
18%
82%
2003
37%
63%
2004
54%
46%
2005
53%
47%
Figure 6
Gasoline oxygen content has been a topic of considerable interest. Concerns over groundwater
contamination from MTBE resulted in various state laws banning or phasing out its use in gasoline. The
Energy Policy Act of 2005 included a renewable content requirement for gasoline and eliminated the RFC
oxygen content requirement. RFC data for 2006, while not analyzed for this report, show that RFC
suppliers continued to use oxygen in RFC even after the requirement was removed in May of 2006, and
that virtually all of this RFC was ethanol-oxygenated. MTBE use in RFC is currently at near zero levels.
EPA finalized Renewable Fuel Standard program regulations in April 2007 to implement the Energy Policy
Act renewable content requirement. Like RFC, these regulations include new recordkeeping and
reporting requirements designed to track the volume of renewable fuel, including ethanol.
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