United States               Air and Radiation          EPA420-F-02-036
Environmental Protection                             September 2002

Office of Transportation and Air Quality
Blue Sky Series Engines
The U.S. Environmental Protection Agency (EPA) has adopted
emission standards for most categories of nonroad engines. Many of
these programs have voluntary emission standards for certifying
engines—which we call Blue Sky Series engines—that operate much
cleaner than the regulations require.
What are Blue Sky Series engines?
They are engines with lower emission levels than our mandatory stan-
dards—usually at least 40 percent cleaner. Meeting this voluntary
standard earns manufacturers a Blue Sky Series designation for these
engines. Manufacturers who choose to get this certification agree to
keep these engines at Blue Sky levels throughout their useful life. We
have a Blue Sky Series for the following engines:
  • land-based nonroad diesel engines (40 CFR part 89)
  • recreational and commercial marine diesel engines (40 CFR part
  • land-based nonroad spark-ignition engines over 25 hp (40 CFR part
Why did EPA create this voluntary program?
We want to encourage manufacturers to introduce innovative technolo-
gies that can reduce emissions below the mandatory levels. These
programs generally have a single qualifying threshold and don't try to
differentiate engines that operate cleaner to meet voluntary standards. In
many cases, technologies are promising, but companies haven't devel-
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oped them enough for us to require a higher degree of control for all

Creating a program of voluntary standards for low-emitting engines,
including provisions to make sure emissions remain low in the field, will
strongly advance the next generation of emission-control technologies.
At the same time, our certification will protect the public against false
claims of environmentally beneficial products.
For diesel engines, the most likely technologies include changes to add
devices that treat exhaust gases or to convert the engine to operate on an
alternative fuel, such as natural gas. Engines with these technologies
have been operating in pilot programs and other limited applications for
several years.

For spark-ignition engines, manufacturers may be able to use technolo-
gies such as advanced fuel injection, electronic controls, and catalytic
converters that automotive manufacturers have already developed to
achieve extremely low emission levels.
Not yet. Although some manufacturers are close to being able to produce
them, as of this printing no manufacturer has certified one. That is
mostly caused by the fact that isolated requests for especially clean-
burning engines don't justify the expense of developing them. As an
operator, manufacturer, or government representative, you can advance
this program by identifying common needs and interests.  Collectively
identifying product needs across the country may at some point help a
manufacturer to justify offering the low-emission engines (and associ-
ated vehicles, equipment, or vessels).
              the                           for the
Once engines become available, states and potential buyers can judge the
costs and benefits of buying low-emission engines. State and local
governments are developing ways to add incentives for producing and
buying these engines. For example,  State governments have started to
specify that companies should use equipment with Blue Sky Series

engines to gain an advantage in bidding on construction contracts. State
and local governments have also started asking companies that need
permits and environmental impact statements for new construction to use
Blue Sky Series engines, if possible.

The emission standards for marine diesel engines don't start for a few
years, so manufacturers may take longer to make these engines avail-
able. Once they do, port authorities may create incentives or require-
ments for operators to buy them.  For example, a port authority could
require a company wanting more presence in a port to use vessels with
low-emitting engines.

For nonroad spark-ignition engines, Blue Sky Series products may have
an additional advantage. Many of these engines power forklifts, sweep-
ers, or other equipment that operates in warehouses, factories, or retail
outlets where individuals could be exposed to exhaust emissions. All
certified engines will have large reductions in exhaust emissions of
carbon monoxide and other pollutants, but Blue Sky Series engines will
offer a higher level of protection.

The Blue Sky Series programs are still very new. Several industry and
government representatives are exploring ideas to increase the effective-
ness of the voluntary emission standards. To find out more about what is
happening and who is active in this field, see "Where can I get more
information" below.
              I get
You can access documents on nonroad engines on the Office of Trans-
portation and Air Quality Web site at:

    www. epa. gov/otaq/nonroad. htm

You can also contact us at:

    U.S. Environmental Protection  Agency
    Office of Transportation and Air Quality
    Assessment and Standards Division
    2000 Traverwood Dr.
    Ann Arbor, MI 48105
    Voice-mail: (734)214-4636
    E-mail: stout.alan@epa.gov