US EPA finalizes particulate matter standards for aircraft engines
17 November 2022
The US Environmental Protection Agency (EPA) finalized PM emission standards and test procedures for civil aircraft engines. The standards apply to new type design and in-production civil aircraft engines. The final standards align with the United Nations’ International Civil Aviation Organization (ICAO) PM standards and will take effect from January 1, 2023.
The regulation replaces the existing smoke opacity number standard for the affected aircraft engines with new, non-volatile particulate matter (nvPM) mass and number emission standards. Remarkably, these are the first-ever particle number emission standards issued by US EPA.
The covered engines are subsonic turbofan and turbojet aircraft engines with rated output (maximum thrust available for takeoff) greater than 26.7 kN. These aircraft engines are used by civil subsonic jet airplanes generally for the purpose of commercial passenger and freight aircraft, as well as larger business jets.
The new standards and test procedures are equivalent to the engine standards adopted by the UN International Civil Aviation Organization (ICAO) in 2017 and 2020. The EPA, as well as the US Federal Aviation Administration (FAA), actively participated in the ICAO proceedings in which the ICAO requirements were developed.
The main provisions of the adopted regulation include:
- PM engine emission standards, in the form of both PM mass (mg/kN) and PM number (#/kN), for both new type design and in-production covered engines. The standards for in-production engines apply to engines manufactured after January 1, 2023. The standards for new type designs apply to engines whose initial type certification application is submitted after January 1, 2023. The in-production standards have different emission limits than the standards for new type designs. Compliance with the standards will be determined in accordance with the standard landing and take-off (LTO) test cycle, which is currently used for demonstrating compliance with gaseous emission (NOx, HC, and CO) standards for the covered engines.
- A PM engine emission standard in the form of maximum mass concentration (μg/m3) for covered engines manufactured after January 1, 2023 (which is three years later than the equivalent ICAO standard). Compliance with the PM mass concentration standard will be done using the same test data that is developed to demonstrate compliance with the LTO-based PM mass and number standards. The PM mass concentration standard applies to the highest concentration of PM measured across the engine operating thrust range, not just at one of the four LTO thrust settings.
- New testing and measurement procedures for the PM emission standards and various updates to the existing gaseous exhaust emissions test procedures. These test procedure provisions, included in the EPA regulation by reference, implement the ICAO’s regulations codified in ICAO Annex 16, Volume II.
The EPA will no longer apply the existing smoke number standard for new engines that will be subject to the PM mass concentration standard after January 1, 2023. The EPA will maintain smoke number standards for new engines not covered by the PM mass concentration standard (e.g., in-production aircraft turbofan and turbojet engines with rated output ≤26.7 kN) and for engines already manufactured.
In addition to the new PM standards, the EPA is migrating most of the existing aircraft engine emissions regulations from 40 CFR part 87 to a new 40 CFR part 1031.
Source: US EPA