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| Titel |
Impact of HONO on global atmospheric chemistry calculated with an empirical parameterization in the EMAC model |
| VerfasserIn |
Y. F. Elshorbany, B. Steil, C. Brühl, J. Lelieveld  |
| 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 ; 12, no. 20 ; Nr. 12, no. 20 (2012-10-30), S.9977-10000 |
| Datensatznummer |
250011547
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| Publikation (Nr.) |
 copernicus.org/acp-12-9977-2012.pdf |
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| Zusammenfassung |
| The photolysis of HONO is important for the atmospheric HOx
(OH + HO2) radical budget and ozone formation, especially in polluted
air. Nevertheless, owing to the incomplete knowledge of HONO sources,
realistic HONO mechanisms have not yet been implemented in global models. We
investigated measurement data sets from 15 field measurement campaigns
conducted in different countries worldwide. It appears that the
HONO/NOx ratio is a good proxy predictor for HONO mixing ratios under
different atmospheric conditions. From the robust relationship between HONO
and NOx, a representative mean HONO/NOx ratio of 0.02 has been
derived. Using a global chemistry-climate model and employing this
HONO/NOx ratio, realistic HONO levels are simulated, being about one
order of magnitude higher than the reference calculations that only consider
the reaction OH + NO → HONO. The resulting enhancement of HONO
significantly impacts HOx levels and photo-oxidation products (e.g,
O3, PAN), mainly in polluted regions. Furthermore, the relative
enhancements in OH and secondary products are higher in winter than in
summer, thus enhancing the oxidation capacity in polluted regions,
especially in winter when other photolytic OH sources are of minor
importance. Our results underscore the need to improve the understanding of
HONO chemistry and its representation in atmospheric models. |
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