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| Titel |
Effect of NOx level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes |
| VerfasserIn |
N. L. Ng, P. S. Chhabra, A. W. H. Chan, J. D. Surratt, J. H. Kroll, A. J. Kwan, D. C. McCabe, P. O. Wennberg, A. Sorooshian, S. M. Murphy, N. F. Dalleska, R. C. Flagan, J. H. Seinfeld |
| 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 ; 7, no. 19 ; Nr. 7, no. 19 (2007-10-08), S.5159-5174 |
| Datensatznummer |
250005217
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| Publikation (Nr.) |
 copernicus.org/acp-7-5159-2007.pdf |
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| Zusammenfassung |
| Secondary organic aerosol (SOA) formation from the photooxidation of one
monoterpene (α-pinene) and two sesquiterpenes (longifolene and
aromadendrene) is investigated in the Caltech environmental chambers. The
effect of NOx on SOA formation for these biogenic hydrocarbons is
evaluated by performing photooxidation experiments under varying NOx
conditions. The NOx dependence of α-pinene SOA formation
follows the same trend as that observed previously for a number of SOA
precursors, including isoprene, in which SOA yield (defined as the ratio of
the mass of organic aerosol formed to the mass of parent hydrocarbon
reacted) decreases as NOx level increases. The NOx dependence of
SOA yield for the sesquiterpenes, longifolene and aromadendrene, however,
differs from that determined for isoprene and α-pinene; the aerosol
yield under high-NOx conditions substantially exceeds that under
low-NOx conditions. The reversal of the NOx dependence of SOA
formation for the sesquiterpenes is consistent with formation of relatively
low-volatility organic nitrates, and/or the isomerization of large alkoxy
radicals leading to less volatile products. Analysis of the aerosol chemical
composition for longifolene confirms the presence of organic nitrates under
high-NOx conditions. Consequently the formation of SOA from certain
biogenic hydrocarbons such as sesquiterpenes (and possibly large
anthropogenic hydrocarbons as well) may be more efficient in polluted air. |
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