Quantification of the unknown HONO daytime source and its relation to NO2
Item
Title (Dublin Core)
Quantification of the unknown HONO daytime source and its relation to NO2
Description (Dublin Core)
During the DOMINO (<b>D</b>iel <b>O</b>xidant <b>M</b>echanism <b>I</b>n relation to <b>N</b>itrogen <b>O</b>xides) 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 NO<sub>2</sub>, <i>j</i>(NO<sub>2</sub>) as a proxy for <i>j</i>(HONO). This allowed us to calculate values of the unknown HONO daytime source. This unknown HONO source, normalized by NO<sub>2</sub> mixing ratios and expressed as a conversion frequency (% h<sup>−1</sup>), showed a clear dependence on <i>j</i>(NO<sub>2</sub>) with values up to 43% h<sup>−1</sup> at noon. We compared our unknown HONO source with values calculated from the measured field data for two recently proposed processes, the light-induced NO<sub>2</sub> conversion on soot surfaces and the reaction of electronically excited NO<sub>2</sub>* with water vapour, with the result that these two reactions normally contributed less than 10% (<1% NO<sub>2</sub> + soot + <i>h</i>ν; and <10% NO<sub>2</sub>* + H<sub>2</sub>O) 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(<sup>1</sup>D)) integrated over the day.
Creator (Dublin Core)
Sörgel, M.
Regelin, E.
Bozem, H.
Diesch, J.-M.
Drewnick, F.
Fischer, H.
Harder, H.
Held, A.
Hosaynali-Beygi, Z.
Martinez, M.
Zetzsch, C.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-11-10433-2011
https://acp.copernicus.org/articles/11/10433/2011/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
