The HONO source is a device for the continuous generation of pure HONO mixtures in humidified air with a flow rate of 0.5 – 2 l/min. HONO formation is based on the reaction of dilute NaNO2and H2SO4 solution, similar to the study by Taira and Kanda (1990) [[i]]. In contrast to this study, however, a temperature-controlled stripping coil is used as a liquid/gas reactor instead of a bubbler, as described by Kleffmann et al. [[ii]], which show a much faster time response of a few minutes (see Fig. 1).

Fig.1: Example of the variation of the HONO concentration by changing the nitrite concentration. Each data point corresponds to a period of 30 s. The time response of the HONO-LOPAP instrument used here to measure HONO was 3 minutes.

[[i]] Taira, M., Y. Kanda: Continuous Generation System for Low-Concentration Gaseous Nitrous Acid, Anal. Chem.,1990, 62, 630-633.
[[ii]] Kleffmann, J., T. Benter, P. Wiesen: Heterogeneous Reaction of Nitric Acid with Nitric Oxide on Glass Surfaces under Simulated Atmospheric Conditions, J. Phys. Chem. A, 2004, 108, 5793-5799.

In cooperation with:

PD Dr. Joerg Kleffmann
Physical Chemistry/FB C
University of Wuppertal
Gauss Street 20
D-42097 Wuppertal
Germany
PHONE: +49 202 439 2515
FAX: +49 202 439 2505 or 2757
Email: kleffmann@uni-wuppertal.de
www.physchem.uni-wuppertal.de