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Titel |
Quantification of the unknown HONO daytime source and its relation to NO2 |
VerfasserIn |
M. Sörgel, E. Regelin, H. Bozem, J.-M. Diesch, F. Drewnick, H. Fischer, H. Harder, A. Held, Z. Hosaynali-Beygi, M. Martinez, C. Zetzsch |
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 ; 11, no. 20 ; Nr. 11, no. 20 (2011-10-20), S.10433-10447 |
Datensatznummer |
250010135
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Publikation (Nr.) |
copernicus.org/acp-11-10433-2011.pdf |
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Zusammenfassung |
During the DOMINO (Diel Oxidant Mechanism
In relation to Nitrogen Oxides) campaign in
southwest Spain we measured simultaneously all quantities necessary to
calculate a photostationary state for HONO in the gas phase. These
quantities comprise the concentrations of OH, NO, and HONO and the
photolysis frequency of NO2, j(NO2) as a proxy for j(HONO). This
allowed us to calculate values of the unknown HONO daytime source. This
unknown HONO source, normalized by NO2 mixing ratios and expressed as a
conversion frequency (% h−1), showed a clear dependence on
j(NO2) with values up to 43% h−1 at noon. We compared our
unknown HONO source with values calculated from the measured field data for
two recently proposed processes, the light-induced NO2 conversion on
soot surfaces and the reaction of electronically excited NO2* with
water vapour, with the result that these two reactions normally contributed
less than 10% (<1% NO2 + soot + hν; and <10%
NO2* + H2O) to our unknown HONO daytime source. OH production from
HONO photolysis was found to be larger (by 20%) than the "classical"
OH formation from ozone photolysis (O(1D)) integrated over the day. |
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