Web Release Date: August 1,
Ozone-Initiated Chemistry in an Occupied Simulated Aircraft Cabin
s,
m-Tejsen,
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and
International Centre for Indoor Environment and Energy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark, Environmental and Occupational Health Sciences Institute, University of Medicine and Dentistry of New Jersey and Rutgers University, 170 Frelinghuysen Road, Piscataway, New Jersey 08854, Institut für Ionenphysik und Angewandte Physik, University of Innsbruck, Innsbruck, Austria; Civil & Environmental Engineering Department, University of California, Berkeley, California 94720-1710, Indoor Environment Department, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Civil and Environmental Engineering Department, Arizona State University, Tempe, Arizona 85287
Received for review April 11, 2007
Revised manuscript received June 14, 2007
Accepted June 20, 2007
Abstract:
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.
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