title: Ozone-initiated chemistry in an occupied simulated aircraft cabin.
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 approximately 70 to 130 ppb at the lower air exchange rate and from approximately 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.
authors.affiliation: International Centre for Indoor Environment and Energy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark. weschlch@umdnj.edu
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Weschler
authors.forename: Armin
authors.initials: A
authors.lastname: Wisthaler
authors.forename: Shannon
authors.initials: S
authors.lastname: Cowlin
authors.forename: Gyöngyi
authors.initials: G
authors.lastname: Tamás
authors.forename: Peter
authors.initials: P
authors.lastname: Strøm-Tejsen
authors.forename: Alfred T
authors.initials: AT
authors.lastname: Hodgson
authors.forename: Hugo
authors.initials: H
authors.lastname: Destaillats
authors.forename: Jason
authors.initials: J
authors.lastname: Herrington
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
authors.forename: William W
authors.initials: WW
authors.lastname: Nazaroff
mesh_terms: D019342:Acetic Acid / Q000032:analysis; D000096:Acetone / Q000032:analysis; D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D000401:Aircraft; D000447:Aldehydes / Q000032:analysis; D003020:Clothing; D005260:Female; D005561:Formates / Q000032:analysis; D006801:Humans; D007659:Ketones / Q000032:analysis; D008962:Models, Theoretical; D010126:Ozone / Q000737:chemistry*; D013729:Terpenes / Q000032:analysis; D013997:Time Factors; D014691:Ventilation; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D000447:Aldehydes; D005561:Formates; D007659:Ketones; D013729:Terpenes; C030544:formic acid; D000096:Acetone; C008664:nonanal; C021170:decanaldehyde; C029750:methylheptenone; D010126:Ozone; C009884:geranylacetone; C046012:pentanal; D019342:Acetic Acid