EPA to Revise Aircraft Engine Emission Standards
November 30, 2005
The updated standards will be applicable to new engines used in commercial aircraft, including small regional jets, single-aisle aircraft, twin-aisle aircraft and larger aircraft, as well as general aviation and military aircraft that make use of commercial engines, EPA said.
Key Rule Components
The updated NOx standards represent roughly a 16% increase in stringency when compared to existing NOx standards, EPA said.
Commercial aircraft engines with rated thrust greater than 26.7 kilonewtons (kN) that are designed and certified after the rulemaking takes effect will be covered under the new standards. The EPA rulemaking will establish requirements in the U.S. that are in line with ICAO's February 1999 NOx emission standards and March 1997 test procedure amendments.
EPA Works with ICAO
EPA historically worked with the U.S. Federal Aviation Administration (FAA) and ICAO in the development of international aircraft emission standards and decided to do so again since the United Nations specifically established ICAO to ensure safety, equality and consistency among international air transport services, EPA said. The FAA was a logical choice since the agency is responsible for enforcing EPA-adopted aircraft emissions standards.
The revised EPA standards will be equivalent to ICAO standards, which will satisfy obligations under ICAO rules.
By working with ICAO, EPA asserted U.S. manufacturers will be able to certify products for international markets since U.S. engines will meet ICAO compliance requirements. Manufacturers also will be assured emission certification tests meet U.S. requirements and ICAO requirements, EPA said.
Aircraft Engine Emissions
The FAA predicted commercial air carrier flights will increase 9% from 2002 to 2010 and 34% from 2002 to 2020, which means commercial aircraft emissions will increase during a time when other significant mobile and stationary sources are reducing emissions. Statistics show aircraft engines are responsible for about 1% of mobile source NOx emissions in the U.S. on average, although the number grows as high as 4% in airport areas.
Effects on Health and Environment
With NOx emissions leading to ground-level ozone, or smog, EPA devised the National Ambient Air Quality Standards (NAAQS) for several air pollutants, including ozone. Since aircraft emissions can increase the level of air pollutants covered in NAAQS, compliance with the revised aircraft engine standards may assist states in meeting NAAQS as well, EPA said.
In terms of human health, ozone can affect pulmonary and respiratory health, according to EPA. As for environmental risks, particulate matter (PM) can lead to visibility impairment, crop damage, and acid rain.
Aircraft Emissions Timeline
The aircraft emission standards have a 30-year history in the U.S., with new emissions standards being set for different aspect of engines, including:
- 1974: Engine smoke and fuel venting.
- 1984: Hydrocarbon emissions.
- 1997: NOx and carbon monoxide.
- 2005: Updated NOx emission standards (included in this rulemaking).
EPA does not expect U.S. manufacturers to incur additional costs as a result of its rulemaking since previously certified or in-production engine models meet or perform better than the proposed revised standards. Manufacturers also are using test procedures that will bring them in compliance, EPA said.