US aircraft emit roughly 11% of GHG emissions from the US transportation sector; 3% of total US GHG emissions; 29% of GHG emissions from all aircraft globally; and 0.5% of total global GHG emissions, according to the EPA.

The Administrator proposes to make this new finding for commercial aircraft specifically with respect to the same six well-mixed GHGs—carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride—that together were defined as the relevant air pollution in the 2009 Endangerment Finding for light-duty vehicles under section 202(a) of the Clean Air Act. Subsequent to that 2009 finding, EPA adopted GHG emission standards for motor vehicles under section 202 of the CAA.

EPA is seeking comments from all interested parties, including small businesses, on a variety of issues related to setting CO₂ standards for aircraft, including:

• The appropriate effective dates for the potential international CO₂ standard.

• The appropriate stringency levels for the CO₂ standard.

• Whether international standards should apply to new in-production aircraft as well as new aircraft types.

Background. For the past five years, ICAO—a specialized body of the United Nations with 191 member states—has been working with the aviation industry and other stakeholders to develop coordinated, international CO₂ emissions standards for aircraft. EPA and the Federal Aviation Administration, representing the United States, are participating in ICAO’s process in an effort to ensure that resulting policies are equitable across national boundaries. The ICAO standards are expected to be adopted in early 2016. The items now issued by EPA lay the necessary foundation for the development and implementation of a domestic aircraft standard, in accordance with US law and the ICAO process.

The EPA has been engaged in reducing harmful air pollution from aircraft engines since 1973. Section 231 of the Clean Air Act directs the EPA to issue standards addressing aircraft engine pollutant emissions, if in the Administrator’s judgment they cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare. Under the Clean Air Act, the EPA consults with the Federal Aviation Administration (FAA) as it develops aircraft engine emission standards, ensuring that any standards set do not adversely affect safety or increase noise. Section 232 of the Clean Air Act then requires that the FAA ensure compliance with the emissions standards set by the EPA.

The Administrator’s proposed findings come in response to a citizen petition submitted by Friends of the Earth, Oceana, the Center for Biological Diversity, and Earthjustice requesting that the EPA issue a GHG endangerment finding and standards under section 231(a) (2)(A) of the Act for GHG emissions from aircraft engines. This proposal and any final GHG endangerment and cause or contribute findings for aircraft engines are part of preparing for a possible subsequent domestic rulemaking process to adopt the corresponding international aircraft CO₂ emissions standard under CAA section 231.

Once this action is published in the Federal Register, it will be open for a 60-day public comment period. Any future domestic actions toward aircraft engine standards would also be open to public comment and review before they could take effect.

Resources

• Proposed Rule and Advanced Notice of Proposed Rulemaking