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| Titel |
Observations of total RONO2 over the boreal forest: NOx sinks and HNO3 sources |
| VerfasserIn |
E. C. Browne, K.-E. Min, P. J. Wooldridge, E. Apel, D. R. Blake, W. H. Brune, C. A. Cantrell, M. J. Cubison, G. S. Diskin, J. L. Jimenez, A. J. Weinheimer, P. O. Wennberg, A. Wisthaler, 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 ; 13, no. 9 ; Nr. 13, no. 9 (2013-05-02), S.4543-4562 |
| Datensatznummer |
250018625
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| Publikation (Nr.) |
 copernicus.org/acp-13-4543-2013.pdf |
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| Zusammenfassung |
| In contrast with the textbook view of remote chemistry where
HNO3 formation is the primary sink of nitrogen oxides, recent
theoretical analyses show that formation of RONO2 (ΣANs)
from isoprene and other terpene precursors is the primary net chemical
loss of nitrogen oxides over the remote continents where the concentration
of nitrogen oxides is low. This then increases the prominence of questions
concerning the chemical lifetime and ultimate fate of ΣANs. We
present observations of nitrogen oxides and organic molecules collected over
the Canadian boreal forest during the summer which show that ΣANs
account for ~20% of total oxidized nitrogen and that their
instantaneous production rate is larger than that of HNO3.
This confirms the primary role of reactions producing ΣANs as
a control over the lifetime of NOx (NOx = NO +
NO2) in remote, continental environments. However,
HNO3 is generally present in larger concentrations than
ΣANs indicating that the atmospheric lifetime of ΣANs is
shorter than the HNO3 lifetime. We investigate a range of
proposed loss mechanisms that would explain the inferred lifetime of ΣANs
finding that in combination with deposition, two processes are
consistent with the observations: (1) rapid ozonolysis of isoprene nitrates
where at least ~40% of the ozonolysis products release
NOx from the carbon backbone and/or (2) hydrolysis of
particulate organic nitrates with HNO3 as a product.
Implications of these ideas for our understanding of NOx and
NOy budget in remote and rural locations are discussed. |
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