ASHRAE has approved the formation of the Standard 161 committee with the charter to derive an air quality standard specifically for commercial airplanes carrying 19 or more persons. This committee will determine the quality of air necessary to ensure the health, safety, and comfort of the crew and passengers on board commercial airliners. Because of the nature of airliner cabins and the environment in which they operate, many factors come into play which affect cabin air quality. Generally these factors include altitude, geographic location, environmental contaminants present in the area of aircraft operation on the ground, and the condition of the machinery providing and conditioning the air supply. The objective of this research project is to identify potential supply system contaminants, which may be generated by aircraft propulsion engines, and APU's, or ingested from aircraft systems. It will provide information on contaminants produced by aircraft systems with high engine operating hours and cycles. It will provide information on the effect of operating at cruise power at altitude on contaminant levels. It will also identify the extent to which system generated contaminants pass through the environmental control system into the cabin of the aircraft.Principal Investigator: Niren L. Nagda, ENERGEN Consulting, Inc.Conducted: April 1998 - Oct. 2000Keywords: TC 9.3, Transportation Air Conditioning