Proposed  Emission  Standards  for
    New Nonroad Spark-Ignition  Engines,
    Equipment, and Vessels
        The U.S. Environmental Protection Agency (EPA) is proposing
        exhaust emission standards for marine spark-ignition engines
    and small land-based nonroad engines. EPA is also proposing new
    evaporative emission standards for equipment and vessels using these
    engines. These standards would apply only to newly manufactured
    products. The proposed standards would reduce the harmful health
    effects of ozone and carbon monoxide from these engines, equipment,
    and vessels.
    Which engines and vehicles would be covered?
    At EPA, we are proposing new standards for emissions of hydrocarbons (HC), nitro-
    gen 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 proposal because these engines and
    vehicles share many common characteristics. Differences in their design and use led
    us to propose separate emission standards for each group.

         Small Nonroad Spark-Ignition Engines and Equipment: Spark-igni
          tion (SI) nonroad engines rated below 25  horsepower (19 kW) used in
          household and commercial applications, including lawn and garden equip-
          ment, utility vehicles, generators, and a variety of other construction, farm,
          and industrial equipment.
         Marine Spark-Ignition Engines and Vessels: Spark-ignition engines used in
          marine vessels, including outboard engines, personal watercraft, and stern-
          drive/inboard engines.

    Why is EPA regulating these engines, equipment, and
    vessels?
    The engines and vehicles covered by this proposal are significant sources of air pol-
    lution. They account for about 25 percent of mobile source hydrocarbon emissions
    and 30 percent of mobile source carbon monoxide emissions.

                                    Office of Transportation and Air Quality
United States
Environmental Protection                                       EPA420-F-07-032
Agency                                                       April 2007

-------
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 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 and Vehicle Emission Study in 1991, and 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 and construction equipment, locomotives,
commercial marine, and recreational vehicles.
What are the Proposed Requirements?
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 environmental impacts, the number of hours each year that the engine is used, the
need for high-performance operation, and the costs. The proposed requirements for each type of
engine and vehicle are:

Small Nonroad Engines
We are proposing HC+NOx exhaust emission standards of 10 g/kW-hr for Class I engines start-
ing 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 engine combustion and adding
catalysts. These standards are consistent with the requirements recently adopted by the Cali-
fornia Air Resources Board (ARB). We are not proposing new exhaust emission standards for
handheld emissions.

For spark-ignition engines used in marine generators, we are proposing a more stringent Phase
3 CO emission standard of 5 g/kW-hr. This would apply equally to all sizes of engines subject to
the Small SI standards.

We are proposing new evaporative emission standards for both handheld and nonhandheld
equipment. The new standards include requirements to control  fuel tank permeation, fuel line
permeation, and diffusion emissions. For nonhandheld engines we are also proposing to require
control of running losses.

When fully implemented, the proposed standards would result in a 35 percent reduction in
HC+NOx emissions from new engines' exhaust. The proposed standards would result in a 45
percent reduction in evaporative emissions.

Marine spark-ignition engines and vessels
We are proposing a more stringent level of emission standards for outboard and personal wa-
tercraft engines starting with the 2009 model year. The proposed standards for engines above
40 kW are 16 g/kW-hr for HC+NOx and 200 g/kW-hr for CO. For engines below 40 kW, the
standards increase gradually based on the engine's maximum power. We expect manufacturers to
meet these standards with improved fueling systems and other in-cylinder controls. The levels of

                                                Office of Transportation and Air Quality
Emission Standards                                                                2

-------
the standards are consistent with the requirements recently adopted by California ARE with the
advantage of a simplified form of the standard for different power ratings and with a CO stan-
dard.

We are proposing new exhaust emission standards for sterndrive and inboard marine engines.
The proposed standards are 5 g/kW-hr for HC+NOx and 75 g/kW-hr for CO starting with the
2009 model year. We expect manufacturers to meet these standards with three-way catalysts and
closed-loop fuel injection. To ensure proper functioning of these emission control systems in
use, we are proposing a requirement that engines have a diagnostic system for detecting a 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 proposing a CO standard of 350 g/kW-hr. We are also proposing a variety of other special
provisions for these engines to reflect unique operating characteristics and to make it feasible to
meet emission standards using emission credits. These standards are consistent with the require-
ments recently adopted by California ARE, with some adjustment to the provisions for SD/I
high-performance engines and with a CO standard.

The emission standards described above relate to engine operation over a prescribed duty cycle
for testing in the laboratory. We are also proposing "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 proposing new standards to control evaporative emissions for all vessels using marine
spark-ignition engines. The new standards include requirements to control fuel tank perme-
ation, fuel line permeation, and diurnal emissions, including provisions to ensure that refueling
emissions do not increase.

When fully implemented, the proposed standards would result in a 70 percent reduction in
HC+NOx emissions, and a 20 percent reduction in CO from new engines' exhaust. The pro-
posed standards would result in a 70 percent reduction in evaporative emissions.
Health and Environmental Benefits
We estimate that by 2030, the proposed standards would result in significant annual reductions
of pollutant emissions from regulated engine and equipment sources nationwide, including
630,000 tons of volatile organic hydrocarbon emissions, 98,000 tons of NOx emissions, and
6,300 tons of direct particulate matter (PM2.5) emissions. These reductions correspond to sig-
nificant reductions in the formation of ground-level ozone and ambient PM2.5. We also expect
to see annual reductions of 2.7 million tons of carbon monoxide emissions, with the greatest
reductions in areas where there have been problems with individual exposures. The require-
ments in this proposal would result in substantial benefits to public health and welfare and the
environment. We estimate that by 2030, on an annual basis, these emission reductions would
prevent 450 PM-related premature deaths, approximately 500 hospitalizations, 52,000 work days
lost, and  other quantifiable benefits every year. The total estimated annual benefits of this rule
in 2030 are approximately $3.4 billion. Estimated costs in 2030 are many times less at approxi-
mately $240 million.

                                                 Office of Transportation and Air Quality
Emission Standards                                                                  3

-------
Costs
The estimated costs of the new standards range from $9.5 million in 2008 to $620 million in
2037. These control costs are partially offset by estimated annual fuel savings of about $360
million in 2037 once standards are fully implemented. As a result, the net cost of the program in
each year ranges from $6.4 million in 2008 to $260 million in 2037.

The results of the economic impact modeling performed for the Small SI and Marine SI engines
and equipment control programs suggest that the social costs  of those programs are expected
to be about $570 million in 2030 with consumers of these products expected to bear about 66
percent of these  costs. We estimate fuel savings of about $330 million in 2030 that will accrue to
consumers. There are $240 net social costs associated with the program in 2030.
Public Participation Opportunities
We welcome your comments on this proposed rule. Comments will be accepted until
August 3, 2007. All comments should be identified by Docket ID No. EPA-HQ-OAR-2004-
0008 and submitted by one of the following methods:

         Internet: www.regulations.gov
         E-mail: A-and-R-Docket@epa.gov
         Mail:
             Environmental Protection Agency
             Air and Radiation Docket and Information Center (6102T)
             1200 Pennsylvania Avenue NW
             Washington, DC 20460
         Hand Delivery:
             EPA West Building
             EPA Docket Center (Room 3340)
             1301 Constitution Avenue NW
             Washington, DC
For More Information
You can access the rule and related documents on EPA's Office of Transportation and Air Qual-
ity (OTAQ) Web site at:

         www.epa.gov/otaq/equip-ld.htm     or     www.epa.gov/otaq/marinesi.htm

For more information on this rule, please contact the Assessment and Standards Division at:

         U.S. Environmental Protection Agency
         Office of Transportation and Air Quality
         2000 Traverwood Drive
         Ann Arbor, MI 48105
         Information Line:734-214-4636
         E-mail: asdinfo@epa.gov

                                              Office of Transportation and Air Quality
Emission Standards                                                              4

-------