The large-scale air pollution model UNI-DEM (the Unified Danish Eulerian Model) was used together with several carefully selected climatic scenarios. It was necessary to run the model over a long time-interval (sixteen consecutive years) and to use fine resolution on a very large space domain. This caused great difficulties because it was necessary to (a) perform many runs with different input parameters, (b) use huge input files containing the needed meteorological and emission data, (c) resolve many problems related to the computational difficulties, (d) develop and apply carefully prepared parallel codes, (e) exploit efficiently the cache memories of the available computers and (f) store in a proper way huge output files for visualization and animation. It will be described how these difficult tasks have been resolved and many results related to some potentially harmful ozone levels will be presented.
