Aircraft cabin air is frequently contaminated by low concentration odor causing compounds. Activated carbon has a long history of effective application in gas stream treatment. However, little information is available on removing low concentration odor causing compounds in high humidity, cold air environments. Previous research suggests that high relative humidity would severely reduce the effectiveness of activated carbon filters. Operating conditions in aircraft low pressure water separators typically run at 100% relative humidity and 2°C.
Effluent or “breakthrough” curves at 5 ppmv toluene resulted in an adsorption capacity of 0.3 g toluene per gram media at 100% relative humidity compared to a 33% increase at less than 5% relative humidity, i.e. 0.4. Breakthrough analyses were performed at 5 to 40 ppmv toluene at face velocities of 50 to 180 m/min. These results indicate that carbon fiber based filter media hold the promise of effective odor control under conditions of high humidity and low temperature.