United States Air and Radiation EPA420-F-96-015
Environmental Protection September 1996
Agency
Office of Mobile Sources
Environmental
Fact Sheet
Statement of Principles for
Nonroad Diesel Engines
The Environmental Protection Agency (EPA), the California Air
Resources Board (ARE) and the manufacturers ofnonroad diesel
engines recently signed a Statement of Principles (SOP) that serves as
a blueprint to establish a multistep, long-term control program for
nonroad diesel engines. The SOP calls for stringent new oxides of
nitrogen (NOx), hydrocarbon (HC), and particulate matter (PM)
emission standards for land-based nonroad diesel engines and marine
diesel engines under 50 horsepower (hp). The signatories agree to
pursue new standards that will cut NOx and PM emissions by more
than two-thirds from current levels. This historic agreement represents
another example of the type of private/public and federal/state
partnership approach to environmental regulation that EPA is pursuing.
Emissions From Nonroad Diesel Engines
Engines used in nonroad equipment, such as farm tractors, bulldozers,
cranes, and forklifts, are an important part of the agricultural, construc-
tion, logging, and material handling industries. The growth and vitality
of the nonroad sector, as well as the design and operation characteristics
unique to nonroad applications, have increased the contribution of these
engines to air pollution. In particular, emissions from nonroad diesel
engines covered by the SOP contribute approximately 10 percent of total
nationwide emissions of NOx. NOx reacts with HC in the atmosphere to
form urban ozone, or smog. This percentage is even higher in many U.S.
cities with air quality problems. In addition, nonroad diesel engines emit
diesel PM. EPA projects that, with existing control programs, over 80
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percent of diesel PM will come from nonroad engines by 2010 nation-
wide. NOx, ozone, and PM have all been linked to a range of serious
respiratory health problems and a variety of adverse environmental
effects. The nonroad engine manufacturers, EPA, and ARB have
jointly committed to reduce emissions from this category to protect
public health and the environment.
History of the Statement of Principles
This SOP is the result of consultative discussions between EPA, ARB
and industry. These discussions were initiated at the request of states
and environmental groups to address their concerns about the impact
of emissions from both highway and nonroad diesel engines on public
health and the environment. These discussions culminated in an
agreement calling for more stringent emission standards for heavy-
duty highway engines. A Statement of Principles for heavy-duty
highway engines, which was signed by EPA, ARB and engine manu-
facturers in July 1995, noted that EPA and ARB intended to pursue a
similar approach for new nonroad engine emission standards.
Pursuant to the highway effort, EPA, ARB and nonroad engine and
equipment manufacturers began to work together to evaluate new
national controls for nonroad equipment. During the course of these
discussions, EPA sought input from other interested parties including
states, environmental organizations and public interest groups. The
diverse and unique nature of the nonroad sector presented technologi-
cal and implementation challenges very different than those of the
highway sector. The participants were strongly committed, however,
and their persistence has paid off. This agreement strives to signifi-
cantly reduce emissions from nonroad diesel equipment while ensur-
ing regulatory stability and certainty for the nonroad engine and
equipment industries.
Highlights of the Statement of Principles
The Statement of Principles is an agreement which includes new
emission standards and other provisions for nonroad engines that were
either unregulated or lightly regulated, relative to other mobile
sources. The nonroad engines considered in this agreement are com-
pression-ignition engines (i.e., diesel-fueled engines), excluding those
engines used in aircraft, underground mining equipment, locomotives,
and marine applications over 50 horsepower. Highlights include:
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Emission standards in two tiers; each tier phases in by hp level
over a number of years; standard levels (in grams per horse
power-hour) also vary by hp level:
- for engines under 50 hp:
early tier in 1999-2000 7.1-7.8 NOx+HC 0.6-0.75 PM
later tier in 2004-2005 5.6 NOx+HC 0.45-0.6 PM
- for engines 50 hp and over:
early tier in 2001-2006 4.8-5.6 NOx+HC 0.15-0.3PM
later tier in 2006-2008 3.0-3.5 NOx+HC PM not set
Implementation flexibility to engine and equipment manufac-
turers to ease the phase-in of new controls, including special
provisions to assist small manufacturers.
A joint government/industry effort coordinated by EPA to
evaluate the adequacy of the current test procedure for nonroad
engines to ensure emissions control in use.
A technology review by EPA in 2001 to ensure the appropriate-
ness of the Tier 3 standards in the agreement.
Development of a separate research agreement which aims to
develop technologies that can reduce NOx and PM emissions
even more. This cooperative effort will involve many different
stakeholders to explore technologies that can achieve very low
emission levels while preserving performance, reliability,
durability, safety, efficiency, and compatibility with nonroad
equipment.
Health and Environmental Benefits
Reducing NOx, HC and PM emissions from nonroad engines will
provide substantial public health and welfare benefits as well as
important environmental gains. The Agency expects major reductions
in these emissions from the new standards - by as much as two-thirds
from current levels. Preliminary analysis shows that nationwide NOx
inventories will be reduced by approximately 800,000 tons per year by
2010, with benefits increasing annually as the new, cleaner equipment
replaces older machines in the field.
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Next Steps
EPA plans to follow this Statement of Principles with an Advance
Notice of Proposed Rulemaking (ANPRM). EPA will seek input from
all interested parties by soliciting comment on the ANPRM, which will
include the text of the diesel nonroad Statement of Principles. The
Agency will also request comments on a detailed proposal following
the ANPRM.
Control of emissions from spark-ignited engines (i.e., gasoline-fueled
and propane-fueled) is also important for long-term air quality
improvements. EPA and ARB intend to work with the spark-ignited
engine and equipment industry to develop a similar Statement of
Principles for spark-ignited nonroad engines approximately by the end
of 1996.
For More Information
EPA encourages additional information be obtained electronically via
the EPA Internet server or via dial-up modem on the Technology
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); voice helpline: 919-541-5384
Information is also available by calling the NOx/PM information line
at 313-741-7887, or writing to:
U.S. Environmental Protection Agency
National Vehicle and Fuel Emissions Laboratory
Nonroad NOx/PM Team
Engine Programs and Compliance Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
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