Human symptom responses to bioeffluents, short-chain carbonyls/acids, and long-chain carbonyls in a simulated aircraft cabin environment

Abstract

Occupants of aircraft have reported an array of symptoms related to general discomfort and irritation. Volatile organic compounds (VOCs) have been suggested to contribute to the reported symptoms. VOCs are from products used, bioeffluents from people and oxidation reaction products. Thirty-six healthy, young female subjects rated symptoms and environmental quality during an eight-hour exposure to groups of compounds often present in aircraft: (i) long-chain carbonyls, (ii) simulated bioeffluents, and (iii) short-chain carbonyls/organic acids. Statistically more symptoms were identified for the simulated bioeffluents and, to a lesser extent, short-chain carbonyls/organic acids compared to a control condition, although they remained in the acceptable range. There were three temporal patterns in the environmental quality and symptom reports: (i) an adaptive response (immediate increases followed by a decline); (ii) an apparent physiological effect (increases one to three hours into the exposure that remained elevated); and (iii) no statistical differences in reported environmental quality or symptom severity compared to the control air conditions. Typical concentrations found in aircraft can cause transitory symptoms in healthy individuals questioning the adequacy of current standards. Understanding the effects on individuals sensitive to air pollutants and methods to remove the compounds causing the greatest symptom responses are needed.

Keywords: aircraft cabin; bioeffluents; controlled study; symptom reports; volatile organic compounds.

Figure 1

Controlled Environmental Facility with three rows of aircraft seating.

Figure 2

Temporal changes in perception of environmental quality score for odor intensity for each of the four conditions. Symbol represents the mean and the bar ±one standard error. Scale range is measured as 0cm – 2.8cm: 0 corresponds to “no odor” and 2.8 corresponds to “overpowering odor”.

Figure 3

Temporal changes in symptom score for eye irritation for each of the four conditions. Symbol represents the mean and the bar ±one standard error. Scale range is measured as 0cm – 2.8cm: 0 corresponds to “no irritation” and 2.8 corresponds to “overpowering irritation”.

Figure 4

Temporal changes in symptom score for temperature of the environment for each of the four conditions. Symbol represents the mean and the bar ±one standard error. Scale range is measured as 0 corresponds to “clear acceptable” and 6.7 corresponds to “clearly unacceptable”.