Simulation of the air duality during a field study for the city of Graz

The research project DATE Graz (Dispersion of Atmospheric Trace Elements ta king the city of Graz as an example) aimed at the investigation of mesoscal e gamma pollution dispersion of a city in complex terrain. The winter episo de investigated here was characterised by an anticyclonic fair weather situ ation. Local wind systems developed together with strong temperature invers ions. During such an episode air qualify is dominated by emissions from wit hin the city. The city of Graz is situated in the southeast of the Alps in the transition area of mountainous to flat land. The city itself is located in the valley of the river Mur, which forms a basin surrounded by small mo untains. In order to understand the emitter-receptor relationship a mesosca le dispersion model was applied for the simulation of air quality during th e winter episode. Input for the simulation was the emission inventory and e xtensive meteorological measurement data. Results of the simulation reflect the distinct patterns of daily variations of air quality level measured. T he influence of meteorology, emission patterns and chemical reactions are e vident and can be qualitatively and partly quantitatively simulated by the model. A validation attempt was made using air quality data from the monito ring network. The introduction shows the importance of anticyclonic fair we ather conditions on pollution dispersion in mountainous regions. Section 2 describes the meteorological situation and the instrumentation during the w inter measurement campaign. Section 3 deals with the simulation model, init ial and boundary conditions and the emission inventory for the city. In Sec tion 4 the simulation results are compared to measurements. Finally conclus ions are drawn. (C) 2000 Elsevier Science Ltd. All rights reserved.