HONO measurement by differential photolysis
- 1Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
- 2National Centre for Atmospheric Science (NCAS), University of York, Heslington, York, YO10 5DD, UK
- 3School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
- 4National Centre for Atmospheric Science (NCAS), University of Leeds, Leeds, LS2 9JT, UK
- 5School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
Abstract. Nitrous acid (HONO) has been quantitatively measured in situ by differential photolysis at 385 and 395 nm, and subsequent detection as nitric oxide (NO) by the chemiluminescence reaction with ozone (O3). The technique has been evaluated by Fourier transform infrared (FT-IR) spectroscopy to provide a direct HONO measurement in a simulation chamber and compared side by side with a long absorption path optical photometer (LOPAP) in the field. The NO–O3 chemiluminescence technique is robust, well characterized, and capable of sampling at low pressure, whilst solid-state converter technology allows for unattended in situ HONO measurements in combination with fast time resolution and response.