United States Air and Radiation EPA420-F-03-029
Environmental Protection September 2003
Agency
Office of Transportation and Air Quality
&EPA Regulatory
Announcement
Proposed Aircraft Engine
Emission Standards
The U. S. Environmental Protection Agency (EPA) is proposing to
amend the existing emission standards for oxides of nitrogen (NOx) for
new commercial aircraft engines. These new standards are equivalent
to the latest NOx emission standards of the United Nations
International Civil Aviation Organization (ICAO), and thereby would
bring the United States aircraft standards into alignment with the
international standards.
These standards would go into effect in 2004 and would apply to new
aircraft engines utilized on commercial aircraft that include small
regional jets, single-aisle aircraft, twin-aisle aircraft, and 747s and
larger aircraft. General aviation and military aireran can use commercial
aircraft engines subject to this proposal (e.g., small regional jet engines
are also utilized 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 emis-
sions. 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 emis-
> Printed on Recycled Paper
-------
sions. In the Atlanta area for example, NOx emissions from commercial
aircraft are expected to more than double by 2010 and contribute as
much as 10 percent of mobile source NOx emissions. (These growth
projections do not include the impact of the September 11 terrorists'
attacks and the subsequent economic downturn. However, the Federal
Aviation Administration (FAA) expects the demand for air travel to
recover, and then continue a long-term trend of annual growth in the
United States. Recently, FAA reported that flights of commercial air
carriers will increase by 18 percent from 2002 to 2010 and 45 percent
from 2002 to 2020.)
Health and Environmental Concerns
The emissions from aircraft engines that are being directly controlled by
the standards proposed in this rulemaking are NOx emissions. NOx
emissions are a precursor to the formation of ground-level ozone, also
called smog. Ozone affects human pulmonary and respiratory health.
Also, NOx reacts in the atmosphere to form secondary particulate matter
(PM25), which causes detrimental health effects. In addition, NOx,
ozone, and PM adversely affect the environment in various ways includ-
ing visibility impairment, crop damage, and acid rain.
To protect public health and the environment, EPA has established
National Ambient Air Quality Standards (NAAQS) for several air
pollutants, which includes ozone and PM. Recent air quality data show
that about 111 million people live in areas that violate air quality stan-
dards for ground-level ozone. About 70 million people live in areas that
violate air quality standards for PM. Because aircraft emissions contrib-
ute to increases in these air pollutants, the proposed aircraft engine
standards would help states achieve and/or maintain compliance with the
NAAQS.
History of EPA's Regulation of Aircraft Engine
Emissions
The aircraft emission standards for gas turbine (jet) engine have been in
place for about thirty years. Emission standards apply to essentially all
commercial aircraft, comprising scheduled and freight airlines. Two
classes of aircraft, military and general aviation, are presently not cov-
ered. Emission controls on engine smoke and prohibitions on fuel
venting were instituted in 1974 and have been revised several times
-------
since then. EPA standards for unburned hydrocarbon emissions (HCs),
which align with ICAO HC standards, have been in effect since 1984
(including separate HC standards for gas turbine engines employed in
supersonic aircraft). Also, in May 1997, EPA adopted standards equiva-
lent to the existing ICAO NOx and carbon monoxide (CO) standards.
EPA's Participation in ICAO
EPA has worked with the FAA and ICAO in the development of interna-
tional aircraft emission standards. FAA is responsible for enforcing the
aircraft emissions standards established by EPA. ICAO was established
by the United Nations to ensure safety, equality, and consistency among
international airtransport services. One of ICAO's objectives is to lead
international bodies in the development of standards and procedures for
aircraft engines. The United States is one of 188 participating member
States of ICAO. Under the basic ICAO treaty established in 1944, a
participating nation which elects not to adopt the ICAO standards must
provide a written explanation to ICAO describing why a given standard
is impractical to comply with or not in their national interest. In this
rulemaking, EPA proposes to adopt standards equivalent to the latest
ICAO standards.
Main Components of the Rule
This rulemaking proposes to codify into United States law requirements
equivalent to ICAO's February 1999 NOx emission standards and March
1997 test procedure amendments, thereby bringing the United States
emission standards and test procedures into alignment with the interna-
tionally adopted standards and test procedures. The proposed NOx
emission standards would become effective in the year 2004, and these
standards generally represent about a 16 percent reduction (or increase in
stringency) from the existing NOx standards. These proposed emission
standards would apply to commercial aircraft engines with rated thrust
greater than 26.7 kilonewtons (kN) that are newly certified (and de-
signed) after the effective date of the regulations. General aviation and
military aircraft can use commercial engines subject to this proposal, and
thus, emission benefits would be realized from these type of aircraft.
of Adopting ICAO
This proposed rule would establish consistency between U.S. and inter-
national emission standards and test procedures. Since aircraft engines
-------
are international commodities, there is a commercial benefit to consis-
tency between U.S. and international emission standards and control
program requirements. It would be easier for manufacturers to certify
products for international markets since the U.S. can certify engines for
ICAO compliance. Emission certification tests meeting U.S. require-
ments will also be applicable to all ICAO requirements. In addition to
the economic benefit, this proposed rule would ensure that domestic
commercial aircraft will meet the current ICAO standards, and thus, the
public would be assured they are receiving the air quality benefits of the
international standards.
Nearly all (94 percent) already certified or in-production engine models
currently meet or perform better than the standards we are proposing to
adopt in this proposed rulemaking. In addition, manufacturers have
already been developing improved technology in response to the ICAO
standards. Therefore, there are no additional costs that would be incurred
by the aircraft industry as a result of this proposed 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.
Public Participation Opportunities
The proposal and related documents are available on the Office of
Transportation and Air Quality (OTAQ) Web site at: www.epa.gov/otaq/
aviation.htm. We welcome your comments on this proposal. You can
comment via email by sending a message to aircraft@epa.gov. For
instructions on additional ways to send comments, please see the Federal
Register notice. It is available on the Web site above or by calling the
EPA Air Docket at (202) 566-1742; please refer to Docket No. OAR-
2002-0030. You may submit written comments until December 15, 2003.
We will also hold a public hearing in Washington, DC, on November 13,
2003, at:
U.S. Environmental Protection Agency
EPA East Building
Room Number 1153
1201 Constitution Avenue, N.W.
Washington, DC 20004
Telephone: (202) 564-1682
-------
Detailed information about the hearings will be published in the Federal
Register and at www.epa.gov/otaq/aviation.htm.
For information
You can access documents on aircraft emissions electronically on the
OTAQ Web site given above, or by contacting the OTAQ library at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality Library
2000 Traverwood Drive
Ann Arbor, MI 48105
(734)214-4311 & 214-4434
E-mail: Group_AALibrary@epa.gov
------- |