Ozone-Initiated Chemistry in an Occupied Simulated Aircraft Cabin

• Published in: Environmental science & technology Vol. 41; no. 17; pp. 6177 - 6184
• Main Authors: Weschler, Charles J, Wisthaler, Armin, Cowlin, Shannon, Tamás, Gyöngyi, Strøm-Tejsen, Peter, Hodgson, Alfred T, Destaillats, Hugo, Herrington, Jason, Zhang, Junfeng (Jim), Nazaroff, William W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.09.2007
• Subjects: Acetic Acid - analysis; Acetone - analysis; Air Movements; Air Pollutants - analysis; Air Pollution, Indoor - analysis; Aircraft; Aldehydes - analysis; Analytical chemistry; Applied sciences; Atmospheric pollution; Chemicals; Exact sciences and technology; Female; Foreign exchange rates; Formates - analysis; Humans; Indoor pollution and occupational exposure; Ketones - analysis; Models, Theoretical; Ozone; Ozone - chemistry; Pollution; Terpenes - analysis; Time Factors; Ventilation; Volatilization; Air conditioning; Human; Surface reaction; Pollutant behavior; Reaction initiator; Clothing; Reaction product; Proton transfer; Environmental factor; Ozone; Volatile organic compound; Aldehyde; Ketone; Hair (head); Airplane; Health and environment; Cabin; Indoor pollution; Air transportation; Skin; Gaseous phase reaction; Mass spectrometry; Organic compounds; Air change rate
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0708520

We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions:  low air exchange (4.4 h-1), <2 ppb ozone; low air exchange, 61−64 ppb ozone; high air exchange (8.8 h-1), <2 ppb ozone; and high air exchange, 73−77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from ∼70 to 130 ppb at the lower air exchange rate and from ∼30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25−0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA.