Articles | Volume 9, issue 6
Research article
07 Jun 2016
Research article |  | 07 Jun 2016

HONO measurement by differential photolysis

Chris Reed, Charlotte A. Brumby, Leigh R. Crilley, Louisa J. Kramer, William J. Bloss, Paul W. Seakins, James D. Lee, and Lucy J. Carpenter

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.

Short summary
A new method of measuring nitrous acid (HONO), a potent mediator of air quality in the atmosphere as well as an important indoor pollutant, is presented. The new method relies on simple, proven techniques already widely applied to other atmospheric compounds. The technique can be retrofitted to existing analysers at minimal cost, or developed into instruments capable of very fast measurement which allow for more complex analysis of the behaviour of HONO.