Evaluation of the Performance of a Photochemical Dispersion Model in Practical Applications

A photochemical dispersion model has been used to calculate concentrationlevels for an area covering the Netherlands and its surroundings during a given episode. The agreement between measured and calculated concentrations of O₃, and to a somewhat less extent of NO₂, showed to be remarkably good. With this model the influence of traffic emissions, the emissions from industry and the inflow of emissions from outside the area during the episode considered on the existing concentration levels of O₃, NO₂ and NO has been determined. The emissions from outside the area showed to have a large influence on the O₃-concentrations. The influence of industry on O₃- and NO₂-levels is larger than that of traffic.The model has proven to be a valuable tool in determining the influence of different source categories and control regulations on the concentration levels.