Office of Transportation                                EPA420-F-05-015
.. .  ._              and Air Quality                                        November 2005
United States                     '
Environmental Protection  	
Agency

                                                                  for
                   The U. S. Environmental Protection Agency (EPA) is amending the
                   existing emission standards for nitrogen oxides (NOx) for new
                   commercial aircraft engines. These new standards are equivalent to the
                   NOx emission standards (adopted in 1999 for implementation beginning
                   in 2004) of the United Nations International Civil Aviation Organization
                   (ICAO), and will bring the United States aircraft standards into alignment
                   with the international standards.

                   These standards will apply to new aircraft engines used on commercial
                   aircraft including include small regional jets, single-aisle aircraft, twin-
                   aisle aireran, and 747s and larger aircraft. The standards can also apply
                   to general aviation and military aircraft, which sometimes use
                   commercial engines. For example, small regional jet engines are also
                   used in executive general aviation aircraft, and larger commercial
                   aircraft engines may also be used in military transport aircraft.
                   Emissions From Aircraft Engines
                   Aircraft engines contribute about 1 percent of the total U.S. mobile source
                   NOx emissions. However, in some U. S. airport areas, aircraft currently can
                   contribute up to 4 percent of mobile source NOx emissions. Commercial
                   aircraft emissions are a growing segment of the transportation emissions
                   inventory. This growth is occurring at a time when other significant mobile and
                   stationary sources are drastically reducing emissions, thereby accentuating the
                   growth in aircraft emissions. Recently, the Federal Aviation Administration

-------
(FAA) reported that flights of commercial air
carriers will increase by 9 percent from 2002
to 2010 and 34 percent from 2002 to 2020.
Health and Environmental
Concerns
NOx emissions are a precursor to the forma-
tion of ground-level ozone, also called smog.
Ozone affects human pulmonary and respira-
tory health. Also, NOx reacts in the atmo-
sphere to form secondary particulate matter
(PM2 5), which causes detrimental health
effects. In addition, NOx, ozone, and PM
adversely affect the environment in various
ways including visibility impairment, crop
damage, and acid rain.

To protect public health and the environment,
EPAhas established National Ambient Air
Quality Standards (NAAQS) for several air
pollutants, including ozone and PM. Recent air
quality data show that about 159 million
people live in areas that violate air quality
standards for ground-level ozone. About 88
million people live in areas that violate air
quality standards for PM25. Because aircraft
emissions contribute to increases in these air
pollutants, the aircraft engine standards may
help states achieve and/or maintain compliance
with the NAAQS.
       in 1974 for engine smoke (revised
       several times since) and fuel venting
       in 1984 for hydrocarbon emissions
       in 1997 for NOx and carbon monoxide
       in 2005 for additional NOx emission
       standards included in this rulemaking
EPA's Participation in ICAO
EPA has historically worked with the FAA and
ICAO in the development of international
aircraft emission standards. The EAAis respon-
sible for enforcing the aircraft emissions stan-
dards established by EPA. ICAO was estab-
lished by the United Nations to ensure safety,
equality, and consistency among international air
transport services. One of ICAO's objectives is
to lead international bodies in the development
of standards and procedures for aircraft en-
gines. The United States is one of 188 partici-
pating member States. Under the basic ICAO
treaty established in 1944, a participating nation
that elects not to adopt the standards must
provide a written explanation describing why a
given standard is impractical to comply with or
not in its national interest. As long as a partici-
pating nation adopts aircraft emission standards
that are equal to or more stringent than ICAO's
standards, it satisfies its obligations under
ICAO. In this rulemaking, EPA adopts stan-
dards equivalent to the ICAO standards.
History of  EPA's  Regulation of
Aircraft  Engine Emissions
The aircraft emission standards have been in
place for about 30 years and essentially apply
to all commercial aircraft. Over the years,
emission standards have been set for different
aspects of aircraft engines:
Main Components of the  Rule
This rulemaking will codify into United States
law requirements equivalentto ICAO's Febru-
ary 1999 NOx emission standards and March
1997 test procedure amendments. The new
NOx standards generally represent about a 16
percent reduction (or increase in stringency)

-------
from the existing NOx standards. These
emission standards will apply to those com-
mercial aircraft engines with rated thrust greater
than 26.7 kilonewtons (kN) that are newly
certified (and designed) after the effective date
of the regulations - 3 0 days after the date of
publication of this rulemaking in the Federal
Register.
            of Adopting ICAO
Standards
This rule will establish consistency between
U.S. and international emission standards and
test procedures. Because aircraft engines are
international commodities, there is a commer-
cial benefit to consistency between U.S. and
international emission standards and control
program requirements. It will be easier for
manufacturers to certify products for interna-
tional markets because the United States can
certify engines for ICAO compliance. Emission
certification tests meeting U. S. requirements
will also be applicable to all ICAO require-
ments. In addition to the economic benefit, this
rule will ensure that domestic commercial
aircraft will meet the current ICAO standards,
and thus, the public will be assured they are
receiving the air quality benefits of the interna-
tional standards.

Nearly all previously certified or in-production
engine models currently meet or perform better
than the standards EPA is adopting in this
rulemaking. In addition, manufacturers have
already been developing improved technology
in response to the ICAO standards. Therefore,
there are no additional costs that will be
incurred by the aircraft industry as a result of
this rule. In addition, the test procedures
necessary to determine compliance are already
being adhered to by manufacturers during
current engine certification tests. Thus, the
regulations will impose no additional burden on
manufacturers.
For         information
You can access the final rulemaking and related
documents on EPAs Office of Transportation
and Air Quality (OTAQ) Web site at:

       www.epa.gov/otaq/aviation.htm

For more information, please contact EPA at:

       U.S. Environmental Protection Agency
       Assessment and Standards Division
       2000 Traverwood Drive
       Ann Arbor, MI 48105
       Voice-mail: (734)214-4636
       E-mail: asdinfo@epa.gov

-------