Re: Jet fuel question

From: (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

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  
	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

Disclaimer: I am NOT a spokesman for NASA, or any other program or organization.