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| Titel |
Closing the peroxy acetyl nitrate budget: observations of acyl peroxy nitrates (PAN, PPN, and MPAN) during BEARPEX 2007 |
| VerfasserIn |
B. W. LaFranchi, G. M. Wolfe, J. A. Thornton, S. A. Harrold, E. C. Browne, K. E. Min, P. J. Wooldridge, J. B. Gilman, W. C. Kuster, P. D. Goldan, J. A. Gouw, M. McKay, A. H. Goldstein, X. Ren, J. Mao, R. C. Cohen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 19 ; Nr. 9, no. 19 (2009-10-12), S.7623-7641 |
| Datensatznummer |
250007682
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| Publikation (Nr.) |
 copernicus.org/acp-9-7623-2009.pdf |
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| Zusammenfassung |
| Acyl peroxy nitrates (APNs, also known as PANs) are formed from the
oxidation of aldehydes and other oxygenated VOC (oVOC) in the presence of
NO2. There are both anthropogenic and biogenic oVOC precursors to APNs,
but a detailed evaluation of this chemistry against observations has proven
elusive. Here we describe measurements of PAN, PPN, and MPAN along with the
majority of chemicals that participate in their production and loss,
including OH, HO2, numerous oVOC, and NO2. Observations were made
during the Biosphere Effects on AeRosols and Photochemistry Experiment
(BEARPEX 2007) in the outflow of the Sacramento urban plume. These
observations are used to evaluate a detailed chemical model of APN ratios
and concentrations. We find that the ratios of APNs are nearly independent
of the loss mechanisms and thus an especially good test of our understanding
of their sources. We show that oxidation of methylvinyl ketone,
methacrolein, methyl glyoxal, biacetyl and acetaldehyde are all significant
sources of the PAN+peroxy acetyl (PA) radical reservoir, accounting for
26%, 2%, 7%, 20%, and 45%, of the production rate on average
during the campaign, respectively. At high temperatures, when upwind
isoprene emissions are highest, oxidation of non-acetaldehyde PA radical
sources contributes over 60% to the total PA production rate, with
methylvinyl ketone being the most important of the isoprene-derived sources.
An analysis of absolute APN concentrations reveals a missing APN sink that
can be resolved by increasing the PA+∑RO2 rate constant by a
factor of 3. |
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