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Published September 16, 2006 | Published + Supplemental Material
Journal Article Open

Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes


The photooxidation of isoprene, eight monoterpenes, three oxygenated monoterpenes, and four sesquiterpenes were conducted individually at the Caltech Indoor Chamber Facility under atmospherically relevant HC:NO_x ratios to monitor the time evolution and yields of SOA and gas-phase oxidation products using PTR-MS. Several oxidation products were calibrated in the PTR-MS, including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone, methacrolein + methyl vinyl ketone; other oxidation products were inferred from known fragmentation patterns, such as pinonaldehyde; and other products were identified according to their mass to charge (m/z) ratio. Numerous unidentified products were formed, and the evolution of first- and second-generation products was clearly observed. SOA yields from the different terpenes ranged from 1 to 68%, and the total gas- plus particle-phase products accounted for ∼50–100% of the reacted carbon. The carbon mass balance was poorest for the sesquiterpenes, suggesting that the observed products were underestimated or that additional products were formed but not detected by PTR-MS. Several second-generation products from isoprene photooxidation, including m/z 113, and ions corresponding to glycolaldehyde, hydroxyacetone, methylglyoxal, and hydroxycarbonyls, were detected. The detailed time series and relative yields of identified and unidentified products aid in elucidating reaction pathways and structures for the unidentified products. Many of the unidentified products from these experiments were also observed within and above the canopy of a Ponderosa pine plantation, confirming that many products of terpene oxidation can be detected in ambient air using PTR-MS, and are indicative of concurrent SOA formation.

Additional Information

© 2006 American Geophysical Union. Received 4 January 2006; revised 18 April 2006; accepted 16 May 2006; published 7 September 2006. This material is based upon work supported by the National Science Foundation under grants 0119510 and 0443448. Additional support was provided by the California Air Resources Board (contract 00-732). A. Lee was supported by a Graduate Research Education Fellowship from the U.S. Department of Energy's Global Change Education Program. The Caltech Indoor Chamber Facility is supported by the U.S. Environmental Protection Agency Science to Achieve Results (STAR) Program grant RD-83107501-0, and the U.S. Department of Energy grant DE-FG02-05ER63983. The authors are grateful to R. Holzinger for help in transporting and installing the PTR-MS in the Caltech Indoor Chamber Facility. We also thank the two anonymous reviewers for their thorough review and helpful comments.

Attached Files

Published - 250-Lee-2006.pdf

Published - jgrd12898-sup-0008-t07.txt

Supplemental Material - jgrd12898-sup-0001-t01.txt

Supplemental Material - jgrd12898-sup-0002-t02.txt

Supplemental Material - jgrd12898-sup-0003-t03a.txt

Supplemental Material - jgrd12898-sup-0004-t03b.txt

Supplemental Material - jgrd12898-sup-0005-t04.txt

Supplemental Material - jgrd12898-sup-0006-t05.txt

Supplemental Material - jgrd12898-sup-0007-t06.txt

Supplemental Material - jgrd12898-sup-0009-t08.txt

Supplemental Material - jgrd12898-sup-0010-t09a.txt

Supplemental Material - jgrd12898-sup-0011-t09b.txt

Supplemental Material - jgrd12898-sup-0012-t09c.txt

Supplemental Material - jgrd12898-sup-0013-t10.txt


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August 22, 2023
October 23, 2023