Ozone in High-Altitude Aircraft Cabins
Jaffe, L.S.; Estes, H.D.
Archives of Environmental Health 9: 61-71
ISSN/ISBN: 0003-9896 PMID: 14160104 DOI: 10.1080/00039896.1964.10663794
Ozone is present in significant quantities in the atmosphere starting above the tropopause and in toxic concentrations in the stratosphere reaching a peak at about 70,000-90,000 ft. The ambient ozone concentration varies with geographic latitude, season of the year, and meteorological factors. The exact cabin concentrations of ozone in various types of current jet air craft at different altitudes are being studied in relation to these factors to determine whether or not an environmental health problem actually exists, particularly for aircrews. Additional data concerning variations in ambient ozone concentrations at normal jet flight altitudes would be valuable in establishing the limits of the existing problem. High ambient ozone concentrations of 5-10 ppm are found at altitudes of 65,000-80,000 ft through which the SST will cruise. The air used for cabin pressurization passes through the compressors very quickly, too quickly to destroy all the ozone present by adiabatic heating. Unacceptable concentrations of ozone will be present in the cabin environment of the SST unless devices are employed, such as catalytic filters or engineering techniques for delaying or increasing the dwell time of the ambient air intake through the compressors long enough for adiabatic heating to destroy or reduce the ozone content below 0.2-0.3 ppm. It is recommended that additional research be performed in the area of time/temperature relationships of air compressors of turbojet, turboramjet, and/or other proposed types of SST propulsion to develop adequate techniques of ozone destruction.