United States Air and Radiation EPA420-F-01-026
Environmental Protection September 2001
Agency
Office of Transportation and Air Quality
for
The U. S. Environmental Protection Agency (EPA) is proposing emission
standards for types of currently unregulated nonroad engines
and vehicles. These standards would apply only to newly manufactured
products. The proposed standards would reduce the harmful health
of ozone and carbon monoxide (CO) from these engines and
vehicles. They would a/so help reduce acute exposure to CO and air
toxics for persons who operate or who work with or near engines,
and address other environmental problems, such as visibility impairment
in our national parks and other wilderness areas.
be
At EPA, we are proposing new standards for emissions of oxides of
nitrogen (NOx), hydrocarbons (HC), and carbon monoxide (CO) from
several groups of previously unregulated nonroad engines and vehicles
that cause or contribute to air pollution. The controls for these engines
and vehicles have been combined into one proposal because these en-
gines and vehicles share many common characteristics. Differences in
their design and use led us to propose separate emission standards for
each group.
« Large Industrial Spark Ignition Engines: Spark-ignition (SI) nonroad
engines rated over 25 horsepower (19 kW) used in commercial and
industrial applications, including forklifts, electric generators,
airport baggage transport vehicles, and a variety of other construc-
tion, farm, and industrial equipment.
i Printed on Recycled Paper
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• Recreational Vehicles: Spark-ignition nonroad engines used in off-
highway motorcycles, all-terrain-vehicles (ATVs), and snowmo-
biles.
« Diesel Marine Engines: Diesel engines rated at or above 50 horse-
power (37 kW) used in recreational boats.
We intended to include in this proposal new exhaust standards
for highway motorcycles and evaporative standards for gasoline-pow-
ered boats. Proposals for these categories are not included in the dead-
line mandated by the courts, unlike the categories contained in this
proposal. We will issue proposals for these remaining categories within
the next few months. Interested parties will have opportunity to com-
ment during the public review period when these additional standards
are proposed.
is and
The engines and vehicles covered by this proposal are significant
sources of air pollution. They account for about 13 percent of mobile
source hydrocarbon emissions, 6 percent of mobile source carbon
monoxide emissions and 3 percent of mobile source oxides of nitrogen
emissions. The proposed standards are expected to reduce CO emis-
sions by 56 percent and HC+NOx emissions by nearly 80 percent from
these sources when fully implemented.
The proposed standards continue the process of establishing nonroad
standards as required by the Clean Air Act. We are required to study
emissions from nonroad engines and vehicles and to set emissions
standards if the level of pollutants from these sources cause or signifi-
cantly contribute to air pollution and, more specifically, if the emissions
of CO, NOx or volatile organic compounds contribute significantly to
the formation of ozone and carbon monoxide in more than one area of
the country currently not meeting ozone and carbon monoxide stan-
dards. We completed the Nonroad Engine and Vehicle Emission Study
in 1991, and in 1994 determined that these sources contribute signifi-
cantly to ozone or CO nonattainment. We have already set emission
standards for most nonroad engines, including farm and construction
equipment, locomotives, commercial marine, and lawnmowers.
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are the
The proposed requirements vary depending on the kind of engine or
vehicle. In developing these requirements, we considered specific
factors for each type. Among the factors considered were the environ-
mental impacts, the number of hours each year that the engine is used,
the need for high-performance vehicles, and the costs. The proposed
requirements for each type of engine and vehicle are:
Large We are proposing a national program to control emissions of CO, NOx
industrial and HC from nonroad spark-ignition engines over 19 kW that are used in
spark- land-based applications (Large SI engines). These engines are used in a
ignition variety of industrial equipment, including forklifts, airport ground-
equipment service equipment, generators, and compressors. They account for
approximately 3 percent of total mobile-source CO, NOx and HC emis-
sions nationwide. When fully implemented, the proposed standards
would result in an 85 percent reduction in NOx, 70 percent reduction in
HC emissions and a 90 percent reduction in CO from new engines.
Many Large SI engines are modified automotive engines. While car and
truck engines have seen extensive technological developments, Large SI
engine designs have changed little during this time. Adopting basic
automotive emission-control technologies - electronic fuel systems with
three-way catalytic converters - allows for dramatic improvements to
engine performance and fuel economy, while reducing CO, NOx, and
HC emissions by about 90 percent.
The proposed near-term standards are based on similar requirements
adopted by the California Air Resources Board in 1998. Further engine
testing and a concern for off-cycle emissions led the Agency to propose
several additional provisions for the long term, including:
• More stringent emission standards to more accurately reflect the in-
use deterioration of emission controls
* Transient duty cycle and associated emission standards
* Field-testing procedures and emission standards
« Basic engine diagnostic requirements
• Measures to reduce evaporative emissions from gasoline-fueled
equipment
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Proposed Emission Standards for Large SI Engines (g/kW-hr)
N on road
recreational
engines
and
vehicles
Model Year
2004 - 2006
2007 and later
Testing Type
Duty-cycle testing
(steady-state)
Duty-cycle testing
(transient)
Field-testing
Emission
standards
HC+NOx
. 4.0
3.4
4.7
Alternate emission
standards
CO
37
3.4
5.0
IIC+NOx
—
1.3
1.8
CO
—
27
41
These are spark-ignition nonroad engines used in off-highway motor-
cycles, all-terrain-vehicles (ATV), and snowmobiles. Emissions from
these engines account for approximately 10 percent of HC and 3 percent
of CO total mobile source emissions nationwide.
Recreational Vehicle Exhaust Emission Standards
Vehicle
Model Year [ Emission standards
Snowmobiles
2006
2010
Off-highway
Motorcycles
ATVs
2006
2007 and later
2006
2007 and 2008
2009
20 10 and later
HC
g/kW-hr
100
75
CO
g/kW-hr
275
200
HC+NOx*
g/km
2.0
2.0
2.0
2.0
1.0
1.0
CO*
g/km
25.0
25.0
25.0
25.0
25.0
25.0
Phase-in
100%
100%
50%
100%
50%
100%
50%
100%
* The motorcycle and ATV g/km standards relate to a vehicle test rather
than an engine test. Thus the g/km standards cannot be compared
directly to the g/kW-hr standards for the other sectors. For example, an
ATV emitting 2.0 g/km HC+NOx could emit as much 16 g/kW-hr when
tested on an engine-basis.
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Vehicle by 2020
Vehicle
Snowmobiles
Off-highway motorcycles
ATVs
HC
63%
90%
84%
CO
63%
38%
34%
These are marine diesel engines used on recreational boats. Emissions
marine from recreational marine diesel engines account for approximately 0.5
diesel percent of NOx emissions and 0.2 percent of PM emissions relative to
engines total nationwide mobile-source emissions. When fully implemented, the
proposed standards would result in a 41 percent reduction in HC+NOx
and a 22 percent reduction in PM from new engines.
These engines vary greatly in size, but are generally produced by modi-
fying land-based nonroad diesel engines. The recreational engines share
many features with the counterpart commercial marine diesel engines,
but are generally designed for higher power and greater performance.
Proposed Recreational Marine Diesel Emission Limits and Implementation Dates
Subcategory
power > 37 kW
0.5 < disp < 0.9
0.9 < disp< 1.2
1. 2s disp < 2.5
2.5 s disp
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 proposed standards would require the application of existing gaso-
line or diesel engine technologies in varying degrees, depending on the
type of engine. These technologies would include modified 2-stroke
engine technology (e.g., recalibrating, clean carburetion, fuel system
upgrades), changing from 2-stroke to 4-stroke engine technology, modi-
fied 4-stroke technology (e.g., recalibrating, fuel system upgrades), or
improved diesel combustion and aftercooling.
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The engines and vehicles covered by this proposal are significant sources
of air pollution. We estimate their contribution to total mobile-source
emissions to be 13 percent for HC, 6 percent for CO, and 3 percent for
NOx. When fully implemented, the proposed standards are expected to
reduce CO emissions by more than 50 percent and HC+NOx emissions
by nearly 80 percent from these sources.
When finalized, these standards would help avoid a range of adverse
health effects associated with ambient ozone, CO, and PM levels, espe-
cially in terms of respiratory impairment and related illnesses. They will
also help reduce acute exposure to CO, air toxics, and PM for persons
who operate or who work with or near these engines. They will also
help address other environmental problems, such as regional haze in our
national parks and other Class I areas where recreational vehicles and
marine engines are often used.
Costs
The estimated costs of complying with the standards vary by engine
group. Costs range from about $50 to $200 per engine for snowmobiles,
less than $100 for ATVs to about $600 per engine for recreational marine
diesel engines and Large SI engines. These costs would be offset in
many cases by consumer savings from reduced fuel consumption and
engine maintenance resulting from the application of more efficient
technologies. We estimate that U.S. consumers would save more than
$400 million in fuel annually as a result of these emission-control tech-
nologies.
The proposal and related documents are available at www.epa.gov/otaq.
We welcome your comments on this proposal. For instructions on sub-
mitting written comments, please see the Federal Register notice. You
may submit written comments until December 19, 2001. Please refer to
Docket No. A-2000-01. The address for submitting written comments is:
Margaret Borushko (Docket No. A-2000-01), U. S. Environmental
Protection Agency, Office of Transportation and Air Quality, 2000
Traverwood Drive, Ann Arbor, MI 48105. You may also submit com-
ments by email to nranprm@epa.gov.
Public hearings will be held near Washington, DC on October 24, 2001
and in Denver, CO on October 30, 2001. Detailed information about the
hearings will be published in the Federal Register and at www.epa.gov/
otaq.
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