Comparative assessment of ground-level air quality in the metropolitan area of Prague using local street canyon modelling

Abstract

Metropolitan areas have recently been identified as hotspots in terms of air quality and pollution-related diseases caused by gaseous pollutants and particulate matter primarily from road emissions. This study was carried out to investigate the suitability of the air dispersion modelling for predicting the short-term concentration of selected pollutants within the asymmetric street canyon geometries. The geographic projection covered a modelling domain of 0.5 × 1.4 km, with a grid resolution of 2 m mapped to the receptor site of an operational ambient air quality monitoring station in Prague, Czech Republic. Basic street canyon simulation showed the best performance metric for the prediction of PM10 concentration. High spatiotemporal performance was found by the advanced street canyon simulation in predicting hourly averages of NOx and PM10. The underprediction of the modelled NOx concentration corresponded to those of previous studies with FB value of 0.11 and NMSE <4. The slightly overprediction of PM10 concentration with the obtained FB value of −0.19, the NMSE value of 0.04, and the FAC2 of 0.53 were in agreement with previous modelling work. The simulation results provided additional evidence for the underpredicted concentration of PM2.5 in different model configurations. Advanced street canyon simulation improves the accuracy of ADMS-Urban by a maximum of 34%. The underprediction of short-term emission was graphically analysed in time-series profiles. The validation results and significant remarks greatly contribute to the essential optimization of urban street canyon model to better represent observations in the street canyon geometries of historic European building architectures.