United States Air and Radiation EPA420-F-96-006
Environmental Protection June 1996
Agency
Office of Mobile Sources
4>EPA Environmental Fact Sheet
Heavy-Duty Engine Emission Standards for
Highway Trucks and Buses
The United States Environmental Protection Agency (EPA) is proposing a new com-
bined emission standard for oxides of nitrogen (NOx) and hydrocarbons (HC) from
heavy-duty engines designed for highway trucks and buses. EPA estimates that the
proposed standard would reduce NOx emissions by 50 percent which would signifi-
cantly assist states in meeting and maintaining the ozone standard. The consultation
and consensus building activities which EPA undertook in this initiative culminated in
widespread support from the engine and trucking industries, states, and the environ-
mental community.
How Did This Initiative Evolve?
In response to the need for additional pollution reduction measures at the
national level, EPA held a series of discussions with the California Air Resources
Board (CARB) and representatives of the heavy-duty engine (HDE) manufactur-
ing industry to exchange views on the appropriateness and feasibility of new
emission standards for HDEs. Based on these discussions, a historic Statement of
Principles (SOP) regarding highway HDEs was signed by these parties in July
1995.
EPA issued an Advance Notice of Proposed Rulemaking (ANPRM) on August
31,1995, which requested comment on the SOP and the agency's plans to
formally propose new HDE emission standards consistent with the SOP. A broad
range of parties responded to the ANPRM, and EPA considered all of these
comments in developing the Notice of Proposed Rulemaking (NPRM).
This initiative has enjoyed unprecedented support from stakeholders. Essen-
tially every major manufacturer of HDEs signed the SOP, and letters of support
have been received from related trade organizations and user groups. States and
organizations representing air pollution control officials have also been strongly
supportive. Comments from the environmental community have been positive
on the major steps forward that this initiative takes.
What Are the Main Components of the Proposed Rule?
Emission Standards
The proposed standards are in the form of combined non methane hydrocar-
bons (NMHC) plus NOx and are presented in units of grams emitted per brake
horsepower-hour (g/bhp-hr). They would apply to diesel and gasoline engines
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and would become effective in model year 2004. Manufacturers would have the
choice of certifying their engines to either of two optional sets of standards:
2.4 g/bhp-hr NMHC + NOx
or
2.5 g/bhp-hr NMHC + NOx
with a limit of 0.5 g/bhp-hr on NMHC
In-Use Emissions Controls
EPA is also proposing new initiatives to encourage engine manufacturers to use
emissions controls that will have a high degree of durability, and will perform
well in use without an unreasonable degree of owner involvement. EPA is also
proposing other basic provisions to help encourage the maintenance and repair
of emissions controls after the regulatory life is reached, especially during en-
gine rebuild.
ABT Provisions
EPA is proposing changes to the averaging, banking, and trading (ABT) provi-
sions to encourage the early introduction of cleaner engines, thus securing
emissions benefits earlier than would otherwise be the case.
Technology Review
A technology review will be undertaken in 1999 to assess industry progress and
propose changes in the standards if necessary. The potential role of fuels in
achieving low HDE emissions is being evaluated now as part of a technical
working group comprised of representatives from EPA, the engine manufactur-
ers, the oil industry and other stakeholders. The results of these technical evalu-
ations will be considered as a part of the 1999 technology review.
How Does The Proposed Rule Provide Flexibility to Industry?
The proposed rule provides flexibility to the industry in three main areas:
• manufacturers have the flexibility of choosing from two optional sets of
standards;
• the time frame for these standards allows for the difficult technological
hurdles to be addressed without large increases in engine costs, resulting
in what EPA believes will be an extremely cost-effective way of making
necessary air quality gains; and
• the flexibility provided by ABT lowers the costs to manufacturers and
makes it easier to meet the technical challenges of lower standards.
In addition, engine manufacturers benefit from national emissions standards
because a single set of emissions requirements applying to engines in trucks and
buses used anywhere in the country allows manufacturers to achieve economies
of scale and to concentrate research and development resources most effectively.
How Much Will the Proposed Rule Cost?
EPA estimates a near term retail price increase of $200-$500 per vehicle, with
costs decreasing to half that amount in five years. This represents less than one
percent of the cost of most new heavy-duty vehicles.
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How Will the Proposed Rule Assist States?
The significant reduction in NOx emissions expected from the proposed stan-
dard will assist the states in meeting the NAAQSs for ozone and PM. NOx emis-
sion inventories are projected to rise by the early 2000s due to continued indus-
trial growth and expansion of motor vehicle usage. This is expected to result in a
significant increase in PM and ground-level ozone. Without further controls,
within the next 20 years, mobile sources will contribute to about half of all NOx
emissions, with highway HDEs representing about a quarter of these mobile
source Nox emissions. Therefore, further NOx control from HDEs on a regional
scale is seen as a cost-effective strategy to control ozone levels especially where
ozone is high over a large region (as in the Midwest and Northeast).
What Are the Health and Environmental Benefits?
The proposed standard is expected to reduce NOx emissions from highway
HDEs by 50 percent over the 1998 standard. In 2020, EPA projects a reduction of
1,215,000 tons per year in ozone precursors and 50,000 tons per year of second-
ary nitrate PM.
This will benefit public health because ozone exposure causes a range of human
pulmonary and respiratory health effects, including chest pain, coughing, and
shortness of breath. In addition to ground-level ozone, the secondary impacts of
NOx include the formation of nitrate PM, acid rain, and eutrophication of
coastal waters. Therefore, reductions in NOx emissions will have considerable
benefits to both public health and the environment.
What Opportunities Exist for Public Participation?
EPA invites comment on all aspects of the NPRM. In July, a public hearing will
be held in Ann Arbor, Michigan, and a public meeting will be held in Los Ange-
les. To schedule a time to speak at the hearing or the meeting, please call Chris
Lieske at 313-668-4584.
For instructions on submitting written comments, please see the Federal Register
notice. It is available from the EPA Air and Radiation Docket by calling 202-260-
7548; please refer to docket number A-95-27. In addition, the NPRM is available
electronically via the EPA Internet server and via dial-up modem on the Tech-
nology Transfer Network (TTN), an electronic bulletin board system (BBS).
World Wide Web: http://www.epa.gov/OMSWWW
TTN BBS: 919-541-5742 (1200-14400 bps, no parity, 8 data bits, 1 stop
bit); voice helpline: 919-541-5384
For further information on this rulemaking, please call the NOx/ PM Heavy-
Duty Engine voice mailbox at 313-741-7887, or write to:
U.S. Environmental Protection Agency National Vehicle and Fuel Emis-
sions Laboratory Highway Heavy-Duty Team 2565 Plymouth Road Ann
Arbor, Michigan 48105
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