EPA Proposes Tier STailpipe and
Evaporative Emission and Vehicle
Fuel Standards
The U.S. Environmental Protection Agency (EPA) is issuing a
proposed rule designed to reduce air pollution from passenger
cars and trucks. Starting in 2017, Tier 3 would set new vehicle emis-
sions standards and lower the sulfur content of gasoline, considering
the vehicle and its fuel as an integrated system. The proposed vehicle
standards would reduce both tailpipe and evaporative emissions from
passenger cars, light-duty trucks, medium-duty passenger vehicles,
and some heavy-duty vehicles. The proposed gasoline sulfur standard
would make emission control systems more effective for both existing
and new vehicles, and would enable more stringent vehicle emissions
standards since removing sulfur allows the vehicle's catalyst to work
more efficiently. The proposed Tier 3 standards are closely coordi-
nated with California's LEV III standards as well as with EPA's and
California's programs for greenhouse gas (GHG) emissions from light-
duty vehicles. EPA is proposing the Tier 3 standards to address public
health issues that exist currently and are projected to continue in the
future as requested in a May 21, 2010 Presidential memorandum.
The Tier 3 program continues the successful transition that began
with EPA's Tier 2 program, finalized in 2000, in which EPA treated
vehicles and fuels as a system to reduce both gasoline sulfur and vehicle
emissions. While there were claims at the time that the program
would cause fuel prices to increase far in excess of EPA's estimates
and would result in closures and fuel supply shortages, the Tier 2
program was a success and resulted in gasoline sulfur reductions of
up to 90 percent and enabled the use of new emission control tech-
nologies in cars and trucks with no serious negative impacts on the refin-
ing industry. EPA's Clean Diesel Program similarly utilized a systems
approach to reducing sulfur emissions from diesel fuels and enabling
cleaner diesel technologies with the Highway Diesel Rule (finalized in
2001) and the Nonroad Diesel Rule (finalized in 2004) again with no
SEPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-F-13-018a
March 2013
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serious negative impacts. Now that the U.S. refining industry routinely pro-
duces lower sulfur fuel products, new market opportunities for international
fuel exports have opened up.
Proposed Tailpipe Emissions Standards
EPA is proposing new tailpipe standards for the sum of non-methane organic gases (NMOG)
and nitrogen oxides (NOX), presented as NMOG+NOX, and for particular matter (PM) that
would apply to all light-duty vehicles and some heavy-duty vehicles. Compared to current
standards, the proposed NMOG and NOX tailpipe standards for light-duty vehicles represent
approximately an 80% reduction from today's fleet average and a 70% reduction in per-vehi-
cle PM standards. Proposed heavy-duty tailpipe standards represent about a 60% reduction in
both fleet average NMOG+NOX and per-vehicle PM standards. EPA is also proposing to extend
the regulatory useful life period during which the standards apply from 120,000 miles to 150,000
miles.
The proposed tailpipe standards include different phase-in schedules that vary by vehicle class,
but generally phase in between model years 2017 and 2025. In addition to the gradual phase-in
schedules, several other proposed provisions would further ease manufacturers' paths to compli-
ance with the stringent new standards. Depending on the standards and the vehicle class, these
flexibility provisions include credits for early compliance and the ability to offset some higher-
emitting vehicles with extra-clean models. EPA is proposing more lead time for small businesses
and small volume manufactures as well as a hardship provision that would allow for additional
time to comply if a manufacturer cannot meet requirements after a good faith effort and would
face severe economic hardship without the additional lead time,
NMOG+NOX Standards: The proposed standards for NMOG+NOX are fleet-average stan-
dards, meaning that a manufacturer calculates the weighted average emissions of the vehicles
it produces in each model year and compares that average to the applicable standard for that
model year. The standards differ by vehicle class and test cycle. Key elements include:
NMOG+NOX Standards for Light-Duty Vehicles and Light-Duty Trucks (vehicles below
8,500 pounds (Ibs) Gross Vehicle Weight Rating (GVWR)), and Medium-Duty Passenger
Vehicles (8,500 to 10,000 Ibs GVWR) :
• As measured on the Federal Test Procedure (FTP), the proposed standards
decline from today's fleet average of 160 milligrams per mile (mg/mi) to 30 mg/mi
by 2025.
• As measured on the Supplemental Federal Test Procedure (SFTP), the proposed
standards decline from today's fleet average of about 100 mg/mi to 50 mg/mi by
2025.
NMOG+NOX Standards for Heavy-Duty Pick-ups and Vans; Class 2b (8,501-10,000 Ibs
GVWR) and Class 3(10,001-14,OOOGVWR)):
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• As measured on the FTP, the proposed fleet average standards decline from a
fleet average of 278 mg/mi to 178 mg/mi for Class 2b vehicles and 451 mg/mi to
247 mg/mi for Class 3 vehicles by 2022,
• Additional standards for emissions measured over a heavy-duty SFTP are being
proposed for the first time and vary by vehicle class and power-to-weight ratio,
PM Standards: The proposed PM standards are expressed on a per-vehicle basis, meaning the
standards would apply to each vehicle separately (i.e., not as a fleet average). EPA is proposing
PM standards that would differ by vehicle class and test cycle. Key elements include:
PM Standards for Light-Duty Vehicles, Light-Duty Trucks, and Medium-Duty Passenger
Vehicles:
• As measured on the FTP, the proposed standard is 3 mg/mi for all vehicles and
for all model years, as compared to today's standard of 10 mg/mi,
• As measured on the US06, a high-speed, fast-acceleration component of the
SFTP, the proposed standard is 10 mg/mi for lighter vehicles and 20 mg/mi for
heavier vehicles,
PM Standards for Heavy-Duty Pick-ups and Vans; Class 2b and 3:
• As measured on the FTP, the proposed PM standards are 8 mg/mi for Class 2b
vehicles and 10 mg/mi for Class 3 vehicles,
• EPA is also proposing PM standards for emissions measured over the SFTP with
standards levels and duty cycles varying by vehicle class and power-to-weight
ratio.
Proposed Evaporative Emission Standards
EPA is proposing more stringent standards designed to eliminate fuel vapor-related evaporative
emissions and improve durability. The proposed evaporative emissions program represents about
a 50 percent reduction from current standards and applies to all light-duty and onroad gasoline-
powered heavy-duty vehicles. As with the tailpipe standards, the evaporative emissions stan-
dards includes phase-in flexibilities, credit and allowance programs, and more lead time for small
businesses and small volume manufactures as well as a hardship provision. EPA is also proposing
to extend the regulatory useful life period during which the standards apply from 120,000 miles
to 150,000 miles. Key elements of the program include:
Evaporative Emissions Standards: Proposed standards over 2-day and 3-day evaporative
emission tests vary by vehicle categories and range from 0.300 g/test to 0.500 for light-
duty vehicles and medium duty passenger vehicles, with 0.600 g/test for onroad gasoline-
powered heavy-duty vehicles,
Bleed Test Requirements: EPA is proposing a new testing requirement referred to as the
bleed emission test. The bleed emissions test standard for light-duty and medium-duty
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passenger vehicles is 0.020 g/test without averaging. The standard for onroad gasoline'
powered heavy-duty vehicles is 0.030 g/test without averaging,
Leak Test and Emission Standard: EPA is proposing to add a new emission standard and
test procedure that would require that the cumulative equivalent diameter of any orifices
or "leaks" not exceed 0.02 inches anywhere in the fuel/evaporative system for light-duty
vehicles, medium-duty passenger vehicles, and some gasoline-powered heavy-duty
vehicles,
Onboard Diagnostic System (OBD) Requirements: EPA is proposing to adopt and
incorporate by reference the California Air Resources Board's (GARB) current OBD
regulations, effective for MY 2017, that would cover all vehicles except those in the
heavier fraction of the heavy-duty vehicle class.
Proposed Fuel Standards
EPA is proposing gasoline sulfur reductions that are critical to enabling manufacturers to comply
across the fleet with the stringent proposed vehicle standards. The proposed gasoline sulfur
standards would also achieve significant immediate benefits by reducing emissions from exist-
ing vehicles. EPA is proposing that federal gasoline contain no more than 10 parts per million
(ppm) of sulfur on an annual average basis by January 1, 2017. In addition, EPA is proposing to
either maintain the current 80-ppm refinery gate and 95-ppm downstream caps or lower them to
50 and 65 ppm, respectively. The proposed Tier 3 gasoline sulfur standards are similar to levels
already being achieved in California, Europe, Japan, South Korea, and several other countries.
For the gasoline sulfur standards, EPA is proposing an averaging, banking, and trading (ABT)
program that would allow refiners and importers to spread out their investments through an early
credit program and rely on ongoing nationwide averaging to meet the 10-ppm sulfur standard,
EPA is also proposing a three-year delay for small refiners and small volume refineries processing
75,000 barrels of crude oil per day or less.
Proposed Changes to Emissions Test Fuel
EPA is proposing to update the federal emissions test fuel to better match today's in-use gaso-
line and also to be forward-looking with respect to future ethanol and sulfur content. The new
test fuel specifications would apply to new vehicle certification, assembly line, and in-use test-
ing. EPA is proposing to transition to the new test fuel during the first few years that the Tier
3 tailpipe and evaporative standards are phasing in. Key changes include moving to a test fuel
containing 15 percent ethanol by volume (seeking comment on 10 percent ethanol by volume),
lowering octane, and lowering the existing sulfur specification to be consistent with proposed
Tier 3 requirements. EPA is also proposing test fuel specifications for E85 for the first time.
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Public Participation Opportunities
You should consult the Federal Register notice for this proposal for more information about how
to submit comments, when the comment period will close, and about where and when public
hearings will be held. A copy of the Federal Register notice can be found on our website listed
below,
EPA welcomes your comments on this proposed rule. Further information on the public com-
ment period may be found on EPA's website (see For More Information below). All comments
should be identified by Docket ID No. EPA-HQ-OAR-2011-0135 and submitted by one of the
following methods:
Internet: www.regulations.gov
E-mail: A-and-R-Docket@epa.gov
Mail:
Environmental Protection Agency
Air and Radiation Docket and Information Center (6102T)
1200 Pennsylvania Avenue NW
Washington, DC 20460
Hand Delivery:
EPA West building
EPA Docket Center (Room 3340)
1301 Constitution Avenue NW
Washington, DC
For More Information
You can access the rule and related documents on EPA's Office of Transportation and Air Qual-
ity (OTAQ) Web site at:
www.epa.gov/otaq/tier3 .htm
For more information on this rule, please contact the U.S. Environmental Protection Agency,
Office of Transportation and Air Quality at:
E-mail: otaq@epa.gov
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