United States
Environmental Protection
Agency
Air and Radiation
EPA420-F-98-028
July 31, 1998
Office of Mobile Sources
<&EPA Announcement/
Update
EPA Releases Tier 2
Report to Congress
In the Tier 2 Report to Congress, the Environmental Protection Agency
examines whether it is appropriate to require more stringent emission
standards for new passenger cars and light duty trucks, which make up
the majority of motor vehicles on the road. This report is the first step
in determining if more stringent vehicle standards are needed to meet
the National Ambient Air Quality Standards (NAAQS). In this
examination, EPA assesses the air quality need, technical feasibility,
and cost effectiveness of more stringent standards. EPA is not making
determinations now. The Report includes a presentation and discussion
of evidence that will support the Agency's determination on future
regulatory actions.
Background
The Clean Air Act Amendments of 1990 set specific exhaust emission
standards, beginning with the 1994 model year, for light duty vehicles
(LDVs), or passenger cars, and light duty trucks (LDTs), which include
sport utility vehicles, minivans and pick-up trucks. These are known as
"Tier 1 standards." The Act requires EPA to study whether further
reductions in emissions from these vehicles should be required—"Tier 2
standards"—which could not take effect before the 2004 model year.
Summary of the Tier 2 Report to Congress
EPA must address the need for further reductions in motor vehicle emis-
sions to attain and maintain the National Ambient Air Quality Standards,
including, at a minimum, three factors:
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Air quality need for more stringent standards: The Report includes
evidence that supports the need for emission reductions beyond those
provided by the Tier 1 standards. Motor vehicle emissions will remain a
significant contributor to air pollution in many areas of the country in
the next 12 years. This assessment includes the finding that, in the time
frame contemplated for potential Tier 2 standards, there will be an air
quality need for emission reductions to aid in meeting and maintaining
the NAAQS for both ozone and particulate matter.
Availability of technology to implement more stringent standards:
The Report examines the technological feasibility of controlling LDV
and LDT emissions beyond the level of control provided for by Tier 1
emission standards. Evidence is presented that more stringent LDV and
LDT emission standards are technologically feasible.
Cost effectiveness of more stringent motor vehicle standards: The
technology projected to be available for the 2004 model year and beyond
appears to be comparable or more cost effective than many alternative
means of emissions reductions.
Issues Related to Potential Tier 2 Standards
There are several issues that EPA will take into account when consider-
ing more stringent emission standards for cars and light duty trucks:
Sulfur in Gasoline: Sulfur in gasoline inhibits the performance of the
catalyst on advanced technology vehicles and has other negative affects
that increase emissions of hydrocarbons, carbon monoxide, oxides of
nitrogen, and particulate matter. The emissions reductions needed from
advanced technology cars and LDTs cannot be achieved unless the sulfur
level in gasoline is also adjusted. EPA will likely address this issue in a
proposed rulemaking at the same time the Agency would propose Tier 2
standards.
Appropriateness of different standards for cars and light duty
trucks: Sport utility vehicles and light pick-up trucks are an increas-
ingly larger portion of passenger vehicles and a growing portion of
emissions from vehicles. EPA will consider whether these heavier
vehicles, which are often used for personal transportation, should have
the same emission standards as passenger cars.
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Gasoline/Diesel Emission Standards: EPA will consider the application
of the same emission standards to vehicles regardless of what fuel is
utilized.
Future Standards: Both the National Low Emission Vehicle Program
(NLEY) and California's proposed second phase of LEV standards set
benchmarks for future vehicle emission controls. EPA will examine
these standards to understand their relationship to potential Federal Tier
2 standards.
Next Steps
Issues raised in the Report will become part of a rulemaking in which
EPA will likely propose new emissions standards and reduced levels of
sulfur in gasoline. The proposal is expected by the end of 1998, and the
final rule by the end of 1999.
For Hore Information
The Tier 2 Report to Congress and related information are available
electronically from the EPA Internet server at:
http://www.epa.gov/OMSWWW/tr2home.htm
For further information on Tier 2 standards, please contact Tad Wysor at
(734) 214-4332 or write to:
U.S. Environmental Protection Agency
2000 Traverwood Dr.
Ann Arbor, Ml 48105
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