Projection of the air quality in Vienna between 2005 and 2020 for NO2 and PM10

Because of frequent exceedances of the actual PM10 and NO2 threshold values in the city of Vienna, a projection of the air quality between 2005 and 2020 was performed using a combined emission–dispersion model system. For the base scenario 2005 the simulated annual mean values were compared with measurement data of 17 monitoring stations. For NO2 concentrations, traffic emissions were identified to be the major source. In the case of PM10 local emissions attribute less than 40% to ambient concentrations, even at hot spots. The remaining share can be explained by long-range transport and secondary particle formation. For both pollutants the current threshold values are exceeded in large areas, especially in the inner city and near main roads. Although the local emissions are expected to decrease by 39% for NOx, by 23% for NO2 and by 34% for PM10 over the projection period, the air quality targets will not be met area-wide until 2020. Furthermore the model system was applied to evaluate the effect of 2 scenarios on the air quality of NO2.