United States Air and Radiation EPA420-F-03-008
Environmental Protection April 2003
Agency
Office of Transportation and Air Quality
oEPA Regulatory
Announcement
Summary of EPA's
Proposed Program for
Low Emission Nonroad
Diesel Engines and Fuel
The U.S. Environmental Protection Agency (EPA) is proposing a
comprehensive national program to reduce emissions from nonroad
diesel engines by integrating engine and fuel controls as a system to
gain the greatest emission reductions. To meet the proposed emission
standards, engine manufacturers will produce new engines with
advanced emission control technologies. The proposed exhaust
emission standards would apply to diesel engines used in most kinds of
construction, agricultural, and industrial equipment. (The proposed
standards do not apply to diesel engines used in locomotives or marine
vessels. EPA has previously established standards for these
categories.) The proposed standards would take effect for new engines
starting as early as 2008 and be fully phased in by 2014. The proposed
standards are phased in over several years to provide adequate lead
time to the engine and equipment manufacturers. The proposed exhaust
emission standards will reduce emissions by more than 90 percent, and
are similar to the requirements for engines used in highway trucks and
buses.
EPA estimates that nonroad diesel engines that would be affected by the
proposal currently account for about 44 percent of total mobile source
diesel particulate matter (PM) emissions and about 12 percent of total
nitrogen oxide (NOx) emissions from mobile sources nationwide. These
proportions are even higher in some urban areas. Because the
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emission control devices can be damaged by sulfur, EPA is also
proposing to reduce the allowable level of sulfur in nonroad diesel fuel
by more than 99 percent. Reducing nonroad emissions is essential to
the efforts of federal, state, local, and tribal governments to improve air
quality in all areas of the country and reduce the adverse health
impacts.
Why We Need To Reduce Emissions From Nonroad
Diesel Engines
Nonroad diesel engines contribute greatly to air pollution in many of our
nation's cities and towns. Over the next several years, nonroad diesel
engines will produce an even greater share of overall emissions as other
emission control programs take effect for cars and trucks and other
nonroad emissions sources.
Nonroad engines being produced today must meet relatively modest
emission requirements and, therefore, continue to emit large amounts of
NOx and PM, both of which contribute to serious public health problems.
Recent air quality data show that about 111 million people live in areas
that violate air quality standards for ground-level ozone, also called
smog. About 70 million people live in areas that violate air quality stan-
dards for PM. In addition, PM, NOx, and ozone adversely affect the
environment in various ways including visibility impairment, crop dam-
age, and acid rain.
Exhaust from diesel engines, which contributes to unhealthy concentra-
tions of fine particles and ozone, is a public health concern. Children,
people with heart and lung disease, and the elderly are most at risk.
Exhaust Emission Standards
Nonroad diesel engines built since 1996 have had to comply with modest
emission standards, with the focus on reducing NOx emissions. Emission
standards have generally not addressed PM emissions. Under the new
proposed emission standards manufacturers are expected to use high-
efficiency control systems to substantially reduce both NOx and PM
emissions. This will achieve a level of control that compares with auto-
mobiles being built today. Table 1 shows the proposed emission standards
(in grams per horsepower-hour) and when these standards would apply
for different sizes of engines. These standards are similar in stringency to
the final standards adopted for 2007 and later diesel-powered trucks and
buses.
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Table 1: Proposed Tier 4 Emission Standards (g/hp-hr)
Rated Power
less than 25 hp
equal to or more
than 25, but less
than 75 hp
equal to or more
than 75, but less
than175hp
equal to or more
than 175, but less
than 750 hp
greater than or equal
to 750 hp
First Year
that
Standards
Apply
2008
2013
2012-2014
2011-2013
2011-2014
PM
0.30
0.02
0.02
0.01
0.01
NOx
—
3.5*
0.30
0.30
0.30
* The 3.5 g/hp-hr standard includes both NOx and nonmethane hydrocarbons.
The proposal includes new provisions to help ensure that emission
control systems perform as well when operating in actual service condi-
tions as in the laboratory. These procedures will allow for testing an
engine's emission levels while the machinery operates in normal service.
Nonroad Diesel Fuel
Just as lead was phased out of gasoline because it damages catalytic
converters in cars, sulfur can contaminate high-efficiency emission
control systems used on diesel engines. Nonroad diesel fuel currently has
sulfur levels of about 3,400 parts per million (ppm) on average. This
proposal would reduce these levels by 99 percent, which is an essential
step in achieving the emission reductions anticipated under the proposal.
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Starting in 2007, fuel sulfur levels in nonroad diesel fuel would be limited
to a maximum of 500 ppm, the same as for current highway diesel fuel.
This limit also covers fuels used in locomotive and marine applications
(though not to the marine residual fuel used by very large engines on
ocean-going vessels). Reducing fuel sulfur levels to 500 ppm or lower
will provide immediate public health benefits by reducing particulate
emissions from engines in the existing fleet of nonroad equipment, with
the added benefit of reducing the cost of maintaining engines.
The proposal includes a second step of fuel controls to a 15-ppm limit on
sulfur content that would apply in 2010. This additional reduction in
sulfur levels will further reduce PM emissions from existing engines.
More importantly, the ultra-low sulfur levels will make it possible for
engine manufacturers to use advanced emission control systems that will
achieve dramatic reductions in both PM and NOx emissions.
Estimated Cost and Benefits
The estimated costs related to low-sulfur fuel take into account all the
necessary changes in both refining and distribution practices. EPA esti-
mates the cost of producing 500 ppm fuel to be on average 2.5 cents per
gallon. Average costs for 15 ppm fuel are estimated to be an additional
2.3 cents per gallon, for a combined cost of 4.8 cents per gallon.
The estimated costs vary widely for equipment of different sizes and for
different applications. For the vast majority of equipment, the cost of
meeting emission standards will be roughly one to two percent compared
with the typical retail price. Costs could range higher for some types of
equipment. As an example, EPA estimates that for a 175-horsepower
bulldozer, it will cost an additional $2,600 to add the advanced emission
control systems to the engine and to design the bulldozer to accommo-
date the modified engine. A new 175-horsepower bulldozer costs ap-
proximately $230,000, so the increased costs are about one percent of
the total purchase price. In addition, engines running on low-sulfur fuel
will have reduced maintenance expenses that we estimate will be equiva-
lent to reducing the cost of the fuel by 3.3 cents per gallon.
The proposal includes six main provisions to reduce the economic impact
of meeting new emission standards and requirements for low sulfur fuels:
(1) The requirements provide sufficient lead time to develop and
produce the necessary advanced emission control systems.
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(2) Engine manufacturers that qualify as small businesses will have
extra time to meet the requirements.
(3) Small refiners will have three to four years of additional lead time
to reduce sulfur levels.
(4) Incentives are proposed to encourage companies to meet require-
ments early if possible.
(5) The proposal allows additional time for equipment manufacturers
to use engines that do not yet meet the new standards.
(6) Companies may petition EPA for relief if the burden of the regula-
tions would cause severe economic hardship.
Reducing NOx and PM emissions from nonroad diesel engines by more
than 90 percent would provide a wide range of public health benefits. We
have estimated that, by 2030, controlling these emissions would annually
prevent 9,600 premature deaths, over 8,300 hospitalizations, and almost
a million work days lost.
Public Participation Opportunities
The proposal and related documents are available at www.epa.gov/
nonroad. EPA welcomes comments on this proposal. You can comment
via e-mail by sending a message to nrt4@epa.gov. See EPA's Web site or
the Federal Register notice for instructions on additional ways to send
comments. You may submit written documents until August 20, 2003.
Public hearings will be held in New York on June 10, Chicago on June
12, and Los Angeles on June 17, 2003. Detailed information about the
hearings will be published in the Federal Register and at www.epa.gov/
nonroad/#hearings.
For Further Information
You can access documents on nonroad diesel engines on the Office of
Transportation and Air Quality Web site at: www.epa.gov/otaq/equip-
hd.htm.
You can also contact EPA at:
U.S. Environmental Protection Agency
Assessment and Standards Division
2000 Traverwood Drive
Ann Arbor, MI 48105
Information line: (734) 214-4636
E-mail: asdinfo@epa.gov
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