United States Air and Radiation EPA420-F-02-037
Environmental Protection September 2002
Agency
Office of Transportation and Air Quality
Regulatory
Announcement
Emission Standards for
New Nonroad Engines
The U.S. Environmental Protection Agency (EPA) is adopting emission
standards for several types of currently unregulated nonroad engines
and vehicles. These standards apply only to newly manufactured
products. This fact sheet gives an overview of the new standards. See
the fact sheets and other documents referenced below for additional
information.
Which engines and vehicles are covered?
We are adopting new standards for emissions of oxides of nitrogen
(NOx), hydrocarbons (HC), and carbon monoxide (CO) from several
groups of previously unregulated nonroad engines. Even though these
different kinds of engines are combined into one rulemaking, the new
requirements reflect differences in the way each type of engine is de-
signed and used.
• Large Industrial Spark-Ignition Engines: Spark-ignition nonroad
engines powered by gasoline, liquid propane gas, or compressed
natural gas rated over 19 kilowatts (kW) (25 horsepower). These
engines are used in commercial and industrial applications, includ-
ing forklifts, electric generators, airport baggage transport vehicles,
and a variety of farm and construction applications.
• Recreational Vehicles: Snowmobiles, off-highway motorcycles, and
all-terrain-vehicles.
• Diesel Marine Engines: Diesel engines over 37 kilowatts (kW) (50
horsepower) used in recreational boats, such as yachts and cruisers.
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The engines covered by this rule are a significant source of air pollution.
They currently account for about 9 percent of HC emissions, 4 percent of
CO emissions, 3 percent of NOx emissions, and 2 percent of PM emis-
sions from mobile sources. If left uncontrolled, by 2020 these engines
will contribute 24 percent of national HC emissions, 6 percent of CO
emissions, 9 percent of NOx emissions, and 5 percent of PM emissions
from mobile sources. HC and NOx emissions form smog and contain
toxic compounds such as benzene, so reducing them will benefit our
health and environment, especially in terms of respiratory impairment and
related illnesses. Some of these engines also emit high levels of CO,
which is especially problematic for people who work with or are other-
wise active near these engines. Many engines operate in warehouses, ice-
skating rinks, or other enclosed areas, where personnel who work with or
near the equipment can experience increased exposure. The new stan-
dards are expected to reduce HC emissions by 71 percent, NOx emissions
by 80 percent, and CO emissions by about 57 percent from these sources.
These new emission standards continue the process of establishing re-
quirements for low-emitting engines as required by Congress. In the
Clean Air Act, Congress directed us to study emissions from all nonroad
engines and vehicles and to set emission standards if the these sources
cause or significantly contribute to air pollution and, more specifically, if
the emissions of CO, NOx or HC contribute significantly to ozone and
carbon monoxide pollution. In 1991, we published the Nonroad Engine
and Vehicle Emission Study. Following that study, we completed a public
process in 1994 to conclude that nonroad engines contribute significantly
to air quality problems related to ozone, CO, and other pollutants. Since
then we have set emission standards for most nonroad engines, including
those used in farm and construction equipment, locomotives, commercial
marine vessels, and lawnmowers. This final rule sets emission standards
for additional categories of nonroad engines and vehicles for which we
have not yet set emission standards.
are the
The new requirements vary depending on the kind of engine or vehicle,
taking into account environmental impacts, usage rates, the need for high-
performance models, costs and other factors. The emission standards
apply to all new engines sold in the United States and any imported
engines manufactured after these standards begin. The requirements for
each type of engine include the following:
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Large These are spark-ignition nonroad engines rated over 19 kW used in a
industrial variety of commercial applications (we refer to these as Large SI en-
spark- gines); most use liquefied petroleum gas, with others operating on gaso-
ignition line or natural gas. These engines contribute to ozone formation and
ambient CO and PM levels in urban areas. In addition, many engines
operate in warehouses, ice-skating rinks, or other enclosed areas, where
personnel who work with or near the equipment can experience increased
exposure.
We are adopting two tiers of emission standards for Large SI engines (see
Table 1). The first tier of standards, scheduled to start in 2004, are based
on a simple laboratory measurement using steady-state procedures. The
Tier 1 standards are the same as those adopted earlier by the California
Air Resources Board for engines used in California.
The Tier 2 standards starting in 2007 are based on transient testing in the
laboratory, which ensures that the engines will control emissions when
they operate under changing speeds and loads in the different kinds of
equipment. We are including an option for manufacturers to certify their
engines to different emission levels to reflect the fact that decreasing
NOx emissions tends to increase CO emissions (and vice versa). Manu-
facturers may generally meet a less stringent CO standard if they certify
an engine with lower HC+NOx emissions. This approach adds an incen-
tive for manufacturers to reduce HC+NOx emissions below the standard,
without taking away the option of producing engines with very low CO
levels for customers concerned about exposing individuals to exhaust
emissions. In addition to these exhaust-emission controls, manufacturers
must take steps starting in 2007 to reduce evaporative emissions, such as
using pressurized fuel tanks.
Table 1: Emission Standards for Large SI Engines*
Tier/Year
Tier 1 starting in 2004
Tier 2 starting in 2007
HC+NOx
4.0 g/kW-k
2.7 g/kW-hr
CO
50 g/kW-hr
4.4 g/kW-hr
*See 40 CFR part 1048 for additional information about alternate standards and field-testing
standards.
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N on road
recreational
engines
and
vehicles
We are also adopting requirements to ensure that engines control emis-
sions during all kinds of normal operation in the field. Tier 2 engines
must have engine diagnostic capabilities that alert the operator to mal-
functions in the engine's emission-control system. The rule also includes
special standards and procedures to allow for measuring emissions
without removing engines from equipment.
These recreational applications include snowmobiles, off-highway
motorcycles, and all-terrain-vehicles (ATVs). These vehicles contribute
to ozone formation and ambient CO and PM levels. They can also
contribute to regional haze and other visibility problems in our national
and state parks. Table 2 shows the exhaust emission standards that apply
to recreational engines. In addition, we are finalizing standards that will
minimize fuel lost through the walls of plastic fuel tanks and rubber
hoses (permeation). These standards are presented in Table 3.
Table 2:
Recreational Vehicle Exhaust Emission Standards
Vehicle
Model Year
Snowmobile
2006
2007 through 2009
2010
2012*
Emission standards
HC
g/kW-hr
100
100
75
75
CO
g/kW-hr
275
275
275
200
Phase-in
50%
100%
Off-highway
Motorcycle
AW
2006
2007 and later
2006
2007 and later
HC+NOx
g/km
2.0
2.0
1.5
1.5
CO
g/km
25.0
25.0
35.0
35.0
50%
100%
50%
100%
"or equivalent per § 1051.103
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Table 3: Permeation Standards for Recreational Vehicles
marine
diesel
engines
Emission Component
Fuel Tank Permeation
Fuel Hose Permeation
Implementation Date
2008
2008
Standard
1.5 g/nf/day
15 g/m2/day
Test Temperature
28°C (82°F)
23°C (73°F)
These are marine diesel engines over 37 kW that are used in yachts,
cruisers, and other types of pleasure craft. Recreational marine engines
contribute to ozone formation and PM levels, especially in marinas,
which are often located in areas with air-quality problems. The standards
are phased in, beginning in 2006, depending on the size of the engine.
Table 4 shows the new standards and implementation dates.
Table 4:
Recreational Marine Diesel Emission Standards and Implementation Dates
Engine Size (based on
displacement in liters per cylinder)
0.5 L/cyl < displ. < 0.9 L/cyl
0.9 L/cyl < disp. < 1.2 L/cyl
1.2 L/cyl < disp. <2.5 L/cyl
disp. > 2.5 L/cyl
Implementation
Date
2007
2006
2006
2009
HC+NOx
g/kW-hr
7.5
7.2
7.2
7.2
PM
g/kW-hr
0.40
0.30
0.20
0.20
CO
g/kW-hr
5.0
5.0
5.0
5.0
the
Vehicles?
The standards will require manufacturers to apply existing engine
technologies in varying degrees, depending on the type of engine. These
technologies would include modified two-stroke engine technology
(such as recalibrating, clean carburetion, fuel system upgrades), chang-
ing from two-stroke to four-stroke engine technology, modified four-
stroke technology (such as recalibrating, fuel system upgrades), or
improved diesel combustion and aftercooling.
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Benefits
When the emission standards for recreational vehicles, recreational
marine diesel engines, and industrial spark-ignition engines are fully
implemented, we expect an overall 72-percent reduction in HC emissions
from these engines, an 80-percent reduction in NOx emissions, and a 56-
percent reduction in CO emissions in 2020. These controls will help
reduce ambient concentrations of ozone, CO and fine PM. In addition,
they will reduce personal exposure for people who operate, work with or
are otherwise close to these engines and vehicles. They will also improve
visibility in national parks.
The human health benefits of this rulemaking include avoiding approxi-
mately 1,000 premature deaths, preventing 1,000 hospital admissions,
reducing 23,400 cases of asthma attacks, and reducing 200,000 days of
lost work. In monetary terms, we estimate these health benefits to be
roughly $8 billion in 2030. There are additional health and welfare
benefits we are unable to quantify.
Costs
Estimated costs for manufacturers to design, certify, and build their
products to meet the new emission standards are expected to range from
$50 to $900 per snowmobile, less than $100 on average for an ATV, less
than $200 on average for off-highway motorcycles, and about $600 for
each recreational marine diesel or Large SI engine. These costs would in
many cases be offset by savings from reduced fuel consumption or engine
maintenance (or both) resulting from the technology improvements to
control emissions. We estimate that nationwide fuel savings will eventu-
ally be greater than 800 million gallons annually in the United States as a
result of these new technologies. Taken in total, this fuel savings more
than exceeds the costs of the rule in any given year.
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I Get
You can access the final rule and related documents on the Office of
Transportation and Air Quality Web site at:
www.epa.gov/otaq/regs/nonroad/2002/cleanrec-final.htm
You can also contact us at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
Assessment and Standards Division
2000 Traverwood Drive
Ann Arbor, MI 48105
Voice-mail: (734) 214-4636
E-mail: asdinfo@epa.gov
See additional fact sheets:
• Environmental Impacts of Newly Regulated Nonroad Engines
(EPA420-F-02-033)
• Frequently Asked Questions from ATV Riders (EPA420-F-02-038)
* Frequently Asked Questions from Off-Highway Motorcycle Riders
(EPA420-F-02-039)
« Frequently Asked Questions from Snowmobile Owners (EPA420-F-02-040)
• Frequently Asked Questions from Owners of Recreational Boats with Diesel
Engines (EPA420-F-02-042)
• Frequently Asked Questions from Facility Managers and Other Owners of
Industrial Spark-ignition Engines (EPA420-F-02-041)
* How to Maintain or Rebuild Engines Certified to EPA Standards
(EPA420-F-02-035)
• Blue Sky Series Engines (EPA420-F-02-036)
• Emission Regulations for Stationary and Mobile Engines (EPA420-F-02-034)
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