ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 24 June 2008
Page Count: 12

Kinetics and Reaction Products of Ozone and Surface-Bound Squalene

Wells, J. R.
Exposure Assessment Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV

Morrison, Glenn C.
Department of Civil, Architectural and Environmental Engineering, Missouri University of Science & Technology, Rolla, MO

Coleman, Beverly K.
Department of Civil and Environmental Engineering, University of California, Berkeley, CA

(Received 6 December 2007; accepted 20 May 2008)

Abstract

Because of the high occupant density in aircraft, the surface chemistry of ozone and squalene, an important component of skin oil, was evaluated. A reaction probability of (45±14)×10⁻⁵ was determined for the reaction of squalene (2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene) with ozone (50 parts per billion (ppb)) on a glass plate surface using the Field and Laboratory Emission Cell (FLEC) Automation and Control System (FACS). To more clearly define part of squalene’s indoor environment degradation mechanism, gas-phase and surface-bound products of the squalene+O₃ reaction were also investigated. Emitted products were captured in solution, derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA), and analyzed by gas chromatography and ion trap mass spectroscopy. The identified squalene+O₃ reaction products were: 6-methyl-5-hepten-2-one (6MHO, ((CH₃)₂CCH(CH₂)₂ C(O)CH₃)), glyoxal (ethanedial, HC(O)C(O)H), 4-oxopentanal (4OPA, CH₃C(O)CH₂CH₂ CH(O)), and 6,10-dimethylundeca-5,9-dien-2-one (geranyl acetone). The compound 5,9,13-trimethyltetradeca-4,8,12-trienal is proposed as the other major squalene+O₃ reaction product. This compound was determined from mass spectrometry coupled with plausible squalene+O₃ reaction mechanisms based on previously published volatile organic compound+O₃ gas-phase reaction mechanisms.

Keywords:
ozone, squalene, oxygenated organic compounds, kinetics, reaction products

Paper ID: JAI101629
DOI: 10.1520/JAI101629
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