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- Title
Measurements of HONO during BAQS-Met.
- Authors
Wentzell, J. J. B.; Schiller, C. L.; Harris, G. W.
- Abstract
Measurements of nitrous acid (HONO) were performed as part of the 2007 Border Air Quality and Meteorology Study (BAQS-Met) at the Harrow Ontario supersite between 20 June and 10 July 2007. Nitrous acid is an important precursor of the hydroxy radical and understanding its chemistry is important to understanding daytime oxidation chemistry. The HONO measurements were made using a custom built Long Path Absorption Photometer (LOPAP). The goal of this work was to shed light on sources of daytime HONO in the border region. During the course of the campaign HONO mixing ratios consistently exceeded expected daytime values by as much as a factor of 6. Mean daytime concentrations of 61 pptv were observed. While HONO decay began at sunrise, minimum HONO values were not measured until the late afternoon. There was little difference between the daytime (mean=1.5%) and night-time (mean=1.7%) ratios of HONO/NO2. Thus there was a very strong daytime source of HONO which is consistent with other recent studies. Correlations of daytime HONO production with a variety of chemical and meteorological parameters indicate that production is dependent on UV radiation, NO2 and water vapour but is not consistent with a simple gas phase process. Apparent rate constants for the production of HONO from photolyticly excited NO2 and water vapour vary from 2.8-7.8×10-13 cm3 molec-1 s-1, during the campaign.
- Subjects
NITROUS acid; ATMOSPHERIC chemistry; ATMOSPHERIC water vapor; HYDROXYL group; NITROGEN oxides; INORGANIC acids
- Publication
Atmospheric Chemistry & Physics Discussions, 2010, Vol 10, Issue 6, p15295
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acpd-10-15295-2010