United States Air and Radiation EPA420-F-00-026
Environmental Protection July 2000
Agency
Office of Transportation and Air Quality
Regulatory
Announcement
Final Emission Standards for 2004
and Later Model Year Highway
Heavy-Duty Vehicles and Engines
The U.S. Environmental Protection Agency (EPA) is issuing a final rule
for the first heavy-duty trucks and buses. In the first phase, EPA is
finalizing new diesel engine standards beginning in 2004 for all diesel
vehicles over 8,500 pounds. Additional diesel standards and test
procedures in this final rule will begin in 2007. Heavy-duty gasoline
engines will be required to meet new, more stringent standards starting
no later than the 2005 model year. The new standards require gasoline
trucks to be 78 percent cleaner and diesel trucks to be more than 40
percent cleaner than today's models.
The second phase of the program will require cleaner diesel fuels and
even cleaner engines, and will reduce air pollution from trucks and
buses by another 90 percent. EPA expects to issue the final rule, to take
effect in 2006-2007, for the second phase of the program by the end of
this year.
Highlights of the Final Rule
Heavy- • EPA is reaffirming a combined standard for smog-causing oxides of
Duty Diesel nitrogen (NOx) and hydrocarbons (HC) of 2.4 grams per brake horse-
Engines power-hour (g/bhp-hr). The current standard for NOx is 4 g/bhp-hr
and the HC standard is 1.3 g/bhp-hr. This standard represents a more
than 40 percent reduction in emissions of NOx, as well as reductions
in HC, from diesel trucks and buses.
> Printed on Recycled Paper
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The rule adds new test procedures and compliance requirements to
ensure that emission standards are met in actual use across a wide
range of operating conditions. These requirements begin in the 2007
model year.
The rule requires on-board diagnostic (OBD) systems for engines
between 8,500 and 14,000 pounds to be phased-in, beginning in 2005.
These systems will identify the failure of emissions control system
components.
Heavy-
Duty
Gasoline
&
Vehicles
Vehicles less than 14,000 pounds gross vehicle weight rating are
subject to emission standards and testing similar to the current pro-
gram for light-duty vehicles and light-duty trucks.
The rule adds new, more stringent emission standards for vehicles
with a gross vehicle weight rating below 14,000 pounds (see table
below). The current NOx and HC standards are 4.0 and 1.1 g/bhp-hr,
respectively.
Gross Vehicle
Weight Rating
8,500 - 10,000 Ibs
10,001 - 14,000 Ibs
HC
0.28 g/mile
0.33 g/mile
NOx
0.9 g/mile
1.0 g/mile
New gasoline heavy-duty engines used in a vehicle with a gross
vehicle weight rating above 14,000 pounds must meet a combined HC
and NOx standard of 1.0 g/bhp-hr. The current NOx and HC standards
are 4.0 and 1.9 g/bhp-hr, respectively.
OBD systems for engines between 8,500 and 14,000 pounds gross
vehicle weight will be phased-in.
The rule incorporates flexibility and incentive mechanisms that will
encourage manufactures of gasoline trucks to meet these standards as
early as 2003 or 2004. Due to the requirements of the Clean Air Act,
the earliest implementation of new emission standards is the 2005
model year.
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and
This rule will reduce emissions of smog-causing NOx by 2.4 million
tons each year when the program is fully implemented in 2030. Ozone
causes a range of health problems related to breathing, including chest
pain, coughing, and shortness of breath. Paniculate matter (PM) is
deposited deep in the lungs and causes premature death, increased
emergency room visits, and increased respiratory symptoms and disease.
With both ozone and PM, children and the elderly are most at risk. In
addition, ozone, NOx, and PM adversely affect the environment in
various ways, including crop damage, acid rain, and visibility impair-
ment.
In addition, there is great concern about the adverse health effects associ-
ated with exposure to diesel exhaust. Exposure is widespread, particu-
larly in urban areas, and according to several national and international
agencies, there is increasing evidence that diesel exhaust or diesel par-
ticulate matter (soot) may cause lung cancer in humans. Non-cancerous
effects such as lung damage and respiratory problems are also associated
with exposure to diesel exhaust.
The significant benefits of this program will come at an average pro-
jected long-term cost increase of less than $400 per vehicle for heavy-
duty diesel engines and less than $300 per vehicle for heavy-duty gaso-
line vehicles and engines.
Background
In 1997, EPA issued a new NMHC+NOx standard for heavy-duty diesel
engines, starting with the 2004 model year, and committed to review the
appropriateness of this standard in 1999. This final rule reaffirms those
standards for diesel engines and finalizes new standards for heavy-duty
gasoline engines.
In 1998, the Agency signed consent decrees with several of the largest
heavy-duty diesel engine manufacturers to address several in-use emis-
sion problems. The final rule contains several new provisions for the
heavy-duty diesel engine manufacturers not contained in the 1997 final
rulemaking that arose because of the issues highlighted by these consent
decrees. These provisions include new emission tests and compliance
requirements that are designed to ensure that heavy-duty diesel engines
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meet emission standards in actual use and over a broad range of operat-
ing conditions. In the consent decrees, the manufacturers agreed to
introduce cleaner new engines and rebuild older engines to cleaner
levels. Under the agreements, the companies will meet emission levels
for heavy-duty diesel engines beyond what the law requires by October
2002.
On May 17, 2000, EPA proposed more stringent emission standards for
heavy-duty vehicles that would reduce smog-causing emissions from
trucks and buses by 95 percent beyond current levels. Soot emissions
also would be reduced by 90 percent beyond current levels. In order to
meet these more stringent standards for diesel engines, the proposal
requires the sulfur content of diesel fuel to be capped at 15 parts per
million - a 97 percent reduction. EPA plans to finalize these standards by
the end of the year, and the standards will take effect in 2006 - 2007.
For
You can access this final rule and related documents electronically on the
Office of Transportation and Air Quality (OTAQ) Web site at:
http ://www. epa.gov/otaq/hd-hwy.htm
You can also contact the OTAQ library for document information at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
NVFEL Library
2000 Traverwood Drive
Ann Arbor, MI 48105
(734)214-4311
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