Simulation of traffic induced Nox-concentrations near the A 12 highway in Austria

The A12 and A13 highways in Tyrol link the regions of Munich and Milan. Both regions possess a strong economy and the highways carry about 60% of the total transit heavy goods traffic in Austria. In recent year's, national as well as EU air quality limits for NO2 have been exceeded at a monitoring site close to the A12 autobahn. In order to assess the pollution levels of NO2 close to the highway, state-of-the-art methodologies for emission- and dispersion modeling were applied in the area. Emissions were calculated utilizing the Passenger cars and heavy duty vehicle emission model (PHEM). Recorded driving cycles for the A12 served as input to the emission model. Air quality was assessed applying Graz lagrangian model (GRAL). Both, GRAL and PHEM have been developed at the Institute for Internal Combustion Engines and Thermodynamics over several years, and have been validated for that purpose. Results show that heavy duty vehicles contribute to about 60% of the total Nox-emissions on the A12 highway. Modeled average Nox-concentrations were found to be in good agreement with observations at four sites near the A12. In addition, the effects of a night-time driving ban for vehicles >7.5 t are discussed.