<title>EPA Finalizes Emission Standards for New Nonroad Spark-Ignition Engines, Equipment, and Vessels</title>
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EPA Finalizes Emission Standards for
New Nonroad Spark-Ignition Engines,
Equipment, and Vessels
The U.S. Environmental Protection Agency (EPA) is adopting new
exhaust emission standards for marine spark-ignition engines and
small land-based nonroad engines. EPA is also adopting evaporative
emission standards for equipment and vessels using these engines.
These standards apply only to newly manufactured products. The
standards will reduce the harmful health effects of ozone and carbon
monoxide from these engines, equipment, and vessels.
Which engines and vehicles are affected?
We are adopting new standards for emissions of hydrocarbons (HC), nitrogen oxides
(NOx), and carbon monoxide (CO) from a variety of nonroad engines, equipment,
and vessels that cause or contribute to air pollution. The controls for these products
have been combined into one rulemaking because these engines and vehicles share
many common characteristics. Differences in their design and use led us to adopt
separate emission standards for each group,
• Small Nonroad Spark-Ignition Engines and Equipment: Spark-ignition (SI)
nonroad engines rated below 25 horsepower (19 kW) used in household and
commercial applications, including lawn and garden equipment, utility
vehicles, generators, and a variety of other construction, farm, and industrial
• Marine Spark-Ignition Engines and Vessels: Spark-ignition engines used
in marine vessels, including outboard engines, personal watercraft, and
Office of Transportation and Air Quality
What are the differences between the final rule and the proposed rule?
Several minor changes from the proposed rule are being adopted in the final rule. These changes
reflect important cooperative efforts between EPA and the regulated industries to implement
cleaner technology as early as possible while still providing communities across the United
States with needed emissions reductions.
First, the implementation dates for Marine Outboard/Personal Watercraft (OB/PWC) and
Sterndrive/Inboard (SD/I) exhaust emissions standards are being delayed one year to allow
sufficient time for manufacturers to convert their entire product line-ups to lower emissions
simultaneously while adopting to supplier changes. Second, modifications are being made to
the Marine SD/I High Performance (>373 kW) exhaust emissions requirements to reflect the
limitations of catalyst technology on these engines. Lastly, we are adopting provisions for cold
weather evaporative emission standards to reflect the capability of fuel line materials and
adding a phase-in for marine diurnal standards. Both of these changes will enhance the
safety of the new requirements.
Why is EPA regulating these engines, equipment, and vessels?
The engines and vehicles covered by this rule are significant sources of air pollution. They
account for about 26 percent of mobile source VOC emissions arid 23 percent of mobile
source carbon monoxide emissions. With the new controls, VOC pollutants will be further
reduced by 34 percent for Small SI engines and 70 percent for Marine SI engines by 2030. With
the new controls, CO pollutants will be further reduced by 9 percent for Small SI engines and
19 percent for Marine SI engines by 2030.
The new 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 significantly contribute
to air pollution and, more specifically, if the emissions of CO, NOx or hydrocarbons 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 standards. We completed the Nonroad Engine
arid Vehicle Emission Study in 1991, arid in 1994 determined that these sources contribute
significantly to ozone or CO nonattainment. We have already set emission standards for most
nonroad engines, including farm arid construction equipment, locomotives, commercial marine,
arid recreational vehicles.
What are the New Requirements?
The new 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 environmental impacts, the number of hours each year that the engine is used, the need for
high-performance operation, and the costs. The new requirements for each type of engine and
Small Nonroad Engines
We are adopting HC+NOx exhaust emission standards of 10 g/kW-hr for Class I engines starting
in the 2012 model year and 8 g/kW-hr for Class II engines starting in the 2011 model year. We
expect manufacturers to meet these standards by improving fuel systems, engine combustion
arid in some cases adding catalysts. These standards are consistent with the requirements recently
adopted by the California Air Resources Board (ARE). We are not adopting new exhaust emission
standards for handheld emissions.
For spark-ignition engines used in marine generators, we are adopting a more stringent Phase 3
CO emission standard of 5 g/kW-hr. This applies equally to all sizes of small SI engines used in
We are adopting new evaporative emission standards for both handheld arid nonhandheld
equipment. The new standards include requirements to control fuel tank permeation, fuel line
permeation, arid diffusion emissions. For nonhandheld engines we also require control of run-
When fully implemented, the new standards will result in a 35 percent reduction in HC+NOx
emissions from new engines' exhaust. The new standards will reduce evaporative emissions by
Marine spark-ignition engines and vessels
We are adopting a more stringent level of emission standards for outboard arid personal water-
craft engines starting with the 2010 model year. The HC+NOx standard for engines producing
less than or equal to 4.3 kW maximum power is 30 g/kWh arid for engines producing greater
than 4.3 kW have a standard that gradually increases based on the engine's maximum power.
The CO standard for engines producing less than or equal to 40 kW gradually increases based
on the engine's maximum power. The CO standard for engines with maximum power greater
than 40 kW is 300 g/kWh. We expect manufacturers to meet these standards with improved
fueling systems and other in-cylinder controls. The federal levels of the HC+NOx standards are
consistent with the requirements recently adopted by California ARE with the addition of a
first-ever CO standard for this category of nonroad engines.
We are adopting new exhaust emission standards for sterndrive and inboard marine engines.
The standards are 5 g/kW-hr for HC+NOx arid 75 g/kW-hr for CO starting with the 2010 model
year. We expect manufacturers to meet these standards with three-way catalysts arid closed-loop
fuel injection. To ensure proper functioning of these emission control systems in use, we will
require manufacturers to diagnose engines for failure in the emission control system.
For sterndrive and inboard marine engines above 373 kW with high-performance characteristics
(generally referred to as "SD/I high-performance engines"), we are adopting a CO standard of
350 g/kW-hr. We are adopting a HC+NOx standard of 20 g/kWh for high-performance engines
producing between 373 and 485 kW in 2010 followed by a tightened standard of 16 g/kWh
in 2011. For high-performance engines producing greater than 485 kW, we are adopting a
HC+NOx standard of 25 g/kWh in 2010 and 22 g/kWh in 2011. We are also adopting a variety
of other special provisions for high-performance engines to reflect unique operating characteristics.
The emission standards described above relate to engine operation over a prescribed duty cycle
for testing in the laboratory. We are also adopting "not-to-exceed" standards that require manu-
facturers to maintain a certain level of emission control when engines operate under normal
speed-load combinations that are not included in the certification duty cycle.
We are also adopting new standards to control evaporative emissions for all vessels using marine
spark-ignition engines. The new standards include requirements to control fuel tank permeation,
fuel line permeation, and diurnal fuel tank vapor emissions, including provisions to ensure that
refueling emissions do not increase.
When fully implemented, the new standards will result in an estimated 70 percent reduction in
HC+NOx emissions and a 50 percent reduction in CO from new SD/I engines' exhaust. The
standards will also result in a 60 percent reduction in HC+NOx emissions from OB/PWC
engines. The new standards will reduce evaporative emissions by about 70 percent.
We estimate that by 2030, the new standards will result in significant annual reductions of pol-
lutant emissions from regulated engine and equipment sources nationwide, including approxi-
mately 600,000 tons of volatile organic hydrocarbon emissions, 130,000 tons of NOx emissions,
and 5,500 tons of direct participate matter (PM25) emissions. These reductions correspond to
significant reductions in the formation of ground-level ozone and ambient PM7,.. We also expect
to see annual reductions of 1.5 million tons of carbon monoxide emissions, with the greatest
reductions in situations where there have been problems with individual exposures. The final
rule will result in substantial benefits to public health and welfare and the environment. We
estimate that by 2030, on an annual basis, these emission reductions will prevent 230 PM-
related premature deaths, between 77 and 350 ozone-related premature deaths, approximately
1,700 hospitalizations and emergency room visits, 23,000 work days lost, 180,000 lost school
days, 590,000 acute respiratory symptoms, and other quantifiable benefits every year. The
total estimated annual benefits of this rule in 2030 are approximately between $1.6 and
$4-4 billion. Estimated costs in 2030 are many times less, at approximately $190 million.
The estimated annualized cost of the new exhaust and evaporative emissions standards is $391
million, assuming a seven percent discount rate over 30 years. The corresponding annualized
fuel savings due to more efficient controls is $155 million. As a result, the net annualized cost of
the program is $236 million.
The results of the economic impact modeling performed for the Small SI and Marine SI engines
i_ <-\ and equipment control programs suggest that the social costs of those programs are expected
to be about $459 million in 2030 with consumers of these products expected to bear about 86
percent of these costs. We estimate fuel savings of about $273 million in 2030 that will accrue to
You can access the rule and related documents on EPA's Office of Transportation and Air
Quality (OTAQ) Web site at:
www.cpa.gov/otaq/cquip-ld.litm or www.cpa.gov/otaq/mariiicsi.litm
For more information on this rule, please contact the Assessment arid Standards Division at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, Ml 48105