Environment: Aircraft Emissions Reduction

In response to air quality concerns, the International Civil Aviation Organization (ICAO) continues to promulgate increasingly stringent standards for emissions during landing and takeoff. In the U.S., regulations under the Clean Air Act have resulted in local authorities, as well as environmental interest groups, demanding action from federal agencies and the air carriers to reduce emissions of nitrogen oxides (NOx), which contribute to toxic ozone production, and other pollutants. The Kyoto Protocol to the UN Framework Convention on Climate Change has, in particular, drawn growing attention to aviation's emissions of carbon dioxide (CO2). At the request of ICAO, a special report on Aviation and the Global Atmosphere was recently published by the Intergovernmental Panel on Climate Change (IPCC) and will serve as the basis for policy to control aircraft cruise emissions in the near future.

Cruise NOx emissions are also a climate concern, as these produce ozone and also control the concentration of methane, both potent greenhouse gases in the upper atmosphere. In addition, recent observations of aircraft contrail behavior have drawn attention to aerosol and particulate (e.g., sulfur, soot) emissions, which are suspected of producing high altitude cirrus clouds that adversely affect Earth's climate. Continued scientific assessment and development of safe and affordable technology options for reducing aircraft engine emissions are important, therefore, to protect the environment and to sustain the growth of aviation. Proposed NASA research and technology objectives are to reduce NOx emissions by a factor of 3 within 10 years and by a factor of 5 within 25 years. The program will focus on developing low emissions and efficient combustors that operate at high pressures and temperatures, while maintaining high levels of engine operability and maintainability. Overall engine efficiency and related CO2 improvements will also be sought, for example, through performance improvements and weight reductions resulting from fewer compressor stages, advanced materials, and supporting subsystems.

The FAA's responsibility will be to develop and implement near-term programs to mitigate the effects of aircraft engine emissions. An important aspect of that job is the development of computer models that give insight into the system-wide consequences of alternative courses of action. Implementation of those models will allow local and national authorities to assess mitigation measures that contribute to improvements in local air quality, and also improve the understanding and mitigation of global climate change.

NASA POC:
Neal Nijhawan
(202) 358-4637
nnijhawan@hq.nasa.gov
http://www.aerospace.nasa.gov/goals/emissions.htm

FAA POC:
Howard Wesoky
(202) 493- 4293
howard.wesoky@faa.gov