Das Projekt "Der Einfluss grenzueberschreitender Luftverschmutzung auf die Luftqualitaet der Schweiz" wird vom Umweltbundesamt gefördert und von Paul Scherrer Institut durchgeführt. Short description: Air quality simulations with UAM for Switzerland have been carried out only for short summer smog periods. Concentration levels at the domain boundaries have been set on the basis of typical background values given in the literature. A sensitivity analysis (Andreani and Keller, 1996) showed that the pollutants concentrations beyond the Swiss boundaries may strongly influence the levels and deposition rates within the country. In this project, concentrations provided by the European models LOTOS and EURAD will be used. They will allow a more reliable estimate of the boundary effects, their sensitivity to emission changes abroad and their diurnal and seasonal dependence. The project will be carried out in the frame of the EUROTRAC II Subproject GLOREAM (Global and Regional Atmospheric Modelling). Further links are established to the EU Projects VOTALP and ECOMONT as well as to the EUROTRAC II Subproject LOOP (Limitation Of Oxidant Production). Project aims: The objective of the project is to evaluate the influence of the emissions and concentrations of air pollutants outside the Swiss borders on the air quality in Switzerland. Together with the domestic emissions, they will be used as an input for the photochemical dispersion model UAM-V which simulates concentrations and deposition rates of air pollutants. The results will be used to assess the impacts of ozone, nitrogen and sulfur compounds as well as particulate matter on ecosystems and human health. Simulations will be performed for selected energy/emissions scenarios predicted for the next decades. Finally, the outcome is intended to be used as an input for the comprehensive assessment of Swiss energy systems which covers economical and ecological aspects, health risks, and global impacts.