The impact of multiphase reactions of NO₂ with aromatics: a modelling approach

N. Lahoutifard (1) , M. Ammann (2) , L. Gutzwiller (2) , B. Ervens (3) , Ch. George (1)

1 LACE - Laboratoire d'Application de la Chimie à l'Environnement
2 PSI - Paul Scherrer Institute
3 TROPOS - Leibniz-Institut für Troposphärenforschung

The impact of multiphase reactions involving nitrogen dioxide (NO₂) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism), was applied for the aqueous phase reactions whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 mm and a liquid water content (LWC) of 50mg m^-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO₂ with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may significantly increase gas phase HONO levels. About one order of magnitude change of HONO concentration was observed with finally, a minor effect on subsequent gas phase daytime photochemistry because of the limited aerosol life time considered.

Domaines: Océan, Atmosphère

N. Lahoutifard, M. Ammann, L. Gutzwiller, B. Ervens, Ch. George. The impact of multiphase reactions of NO₂ with aromatics: a modelling approach. Atmospheric Chemistry and Physics Discussions, 2002, 1, pp.147-172. ⟨hal-00327791⟩