COMPARISON BETWEEN MEASURED AND CALCULATED CONCENTRATIONS OF NITROGEN-OXIDES AND OZONE IN THE VICINITY OF A MOTORWAY

Exhaust emissions from a motorway have been monitored for a year in a joint project by the State of Lower Saxony and Volkswagen. Measurement s were performed by the Fraunhofer Institut fur Toxikologie und Aeroso lforschung in Hannover. As dispersion models alone are unable to repro duce the behaviour of nitrogen oxides and ozone, a simplified air parc el model has been developed. This model includes, in addition to pure dispersion, some basic reactions of nitrogen oxides and ozone, but neg lects reactions with hydrocarbons. A comparison with the observed conc entrations shows that the model gives acceptable results if some restr ictions with respect to meteorological conditions are taken into accou nt.