The validation of our model is based on high quality measurement data. The main source of air quality data originated from the automata stations of the Hungarian Air Quality Network, which is providing official air quality towards the public and EEA. In addition to regular monitoring data we performed campaigns of air sampling at 1.5 m over the pedestrian area of busy crossings and streets. Air samples were analysed with the same accredited devices (using standard chemiluminescent method for NOx according to MSZ EN 14211:2013) as the monitoring stations have. The traffic flow was measured by inductive-loop sensors embedded in the pavement. Simulation results calculated from meteorological and traffic data are in good accordance with real pollution checked with our air samples (level 1.5 m). Indicating the mostly same difference from the data of the nearest monitoring site (level 3 m).