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  • Measurements of acetone and other gas phase product yields from the hydroxyl-initiated oxidation of terpenes by proton-transfer-reaction mass spectrometry (PTR-MS)

Abstract

The atmospheric oxidation of several terpenes appears to be a potentially relevant source of acetone in the atmosphere. Proton-transfer-reaction mass spectrometry was used as an on-line analytical method in a chamber study to measure acetone and other gas phase products from the oxidation of alpha- and beta-pinene initiated by hydroxyl radicals in air and in the presence of NOx.

Primary acetone and pinonaldehyde molar yields of 11+/-2% (one sigma) and 34+/-9% (one sigma), respectively, were found from the reaction between alpha-pinene and the hydroxyl radical. After all alpha-pinene had been consumed, an additional formation of acetone due to the degradation of stable non-radical intermediates was observed. The total amount of acetone formed was 15+/-2% (one sigma) of the reacted alpha-pinene. An upper limit of 12+/-3% (one sigma) for the acetone molar yield from the oxidation of pinonaldehyde was established.

From the reaction between beta-pinene and the hydroxyl radicals, primary acetone and nopinone molar yields of 13+/-2% (one sigma) and 25+/-3% (one sigma), respectively, were observed. Additional amounts of acetone were formed by the further degradation of the primary product. The total amount of acetone formed was 16+/-2% (one sigma) of the reacted beta-pinene. An upper limit of 12+/-2% (one sigma) for the acetone molar yield from the oxidation of nopinone was established.

The observed product yields from alpha- and beta-pinene are in good agreement with other studies using mass-spectrometric and gas chromatographic analytical techniques, but differ significantly from previous studies using spectroscopic methods. Possible reasons for the discrepancies are discussed. ssed.

Additional information

Authors: WISTHALER A, Institut für Ionenphysik, Universität Innsbruck (AT);LINDINGER W, Institut für Ionenphysik, Universität Innsbruck (AT);JENSEN N R, European Commission, Joint Research Centre, Environment Institute, Ispra (IT);WINTERHALTER R, European Commission, Joint Research Centre, Environment Institute, Ispra (IT);HJORTH J, European Commission, Joint Research Centre, Environment Institute, Ispra (IT)
Bibliographic Reference: An article published in: Atmospheric Environment, Vol. 35 (35), (2001), pp. 6181-6191
Record Number: 200214488 / Last updated on: 2002-03-28
Category: PUBLICATION
Original language: en
Available languages: en