From: SCA@pab5.larc.nasa.gov (Scott C. Asbury) Organization: NASA Langley Research Center, Hampton, VA USA Date: 17 Jun 94 23:59:07 References: 1 2 3
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There is a significant amount of legislation pertaining to aircraft and emisisons. The EPA has regulations pertaining to all aircraft powerplants manufactured after December 31, 1979. In general, aircraft contributions to the overall emissions inventory in the U.S. is small, typically less than 1% on a national basis. The major emissions of concern from internal combustion engines are Carbon Monoxide (CO), Hydrocarbons (HC) and Oxides of Nitrogen (NOx). All contribute to photochemical smog formation in large metropolitan areas that affects air quality. CO and NOx can contribute to the "Greehouse Effect". NOx plays an important role in the formation of ozone, which at low altitudes is a pollutant, and also behaves as a greenhouse gas. NOx may contribute to ozone depletion, but this issue needs more study. 1990 EPA data of mobile source emissions (cars, trucks, ships, trains, aircraft, etc.) in Southern California lists the following emissions in tons/day. CO&HC NOx Cars 755 418 Trucks 108 247 Motorcycles 17 2 Trains 2 23 Ships 1 32 Aircraft Commercial 6 14 Military 8 3 GA 1 0.1 As you can see, as compared to cars and trucks aircraft emissions are very small. Another thing to consider, a breakdown of NOx emissions on a global basis. Transportation-Ground 29% Biomass burning 24% Industrial 16% Soil 12% Lightning 11% NH3 oxidation 6% Aircraft 0.6% Misc. 0.4% The EPA under the California Federal Implementation plan is proposing a fine/fee schedule for airlines and general aviation pilots for emissions. If all aircraft operations were to stop today there would be no significant effect on emissions. For more about this subject consult the following paper: AIAA 91-7021 "The Impact of Air Transport on the Environment" Scott Asbury SCA@larc.nasa.gov Disclaimer: I am NOT a spokesman for NASA, or any other program or organization.