The Danish Eulerian Hemispheric Model (DEHM) developed at the National Environmental Research Institute (NERI) in Denmark has been applied for numerous studies of air pollution. DEHM was originally developed with the main purpose of investigating the atmospheric transport of pollutants to the Arctic region, but is now also applied for more local scale environmental problems. The DEHM model has therefore recently been developed with nesting capabilities, which allows for a large mother domain (the Northern Hemisphere) as well as one or two nested domains each with a three times higher horizontal resolution over a limited area. The chemistry version of the model (DEHM-REGINA) has recently been run for a period of 14 years with a nested domain covering Europe and driven by meteorological data from the nested MM5 model. A chemical scheme with 60 species is included and the long-term calculations were made possible due to the application of a new low-cost Linux cluster system recently implemented at NERI. Examples from the validation of the model show that the observed variations and tendencies on both daily to seasonal and longer time scales are well captured for both primary and secondary air pollution components.