Modeling the effects of emission controls in the Netherlands

A photochemical air quality simulation model was applied to an area covering a large portion of The Netherlands and nearby source areas in Belgium and Germany. Simulations of an O₃ episode typical of those that occur during summer months yielded good agreement between predicted and observed O₃ levels. The level of performance for NO₂ and NO was somewhat less than that for O₃. The model was used to study the influence of mobile and stationary sources within the region, as well as the inflow of pollutants from outside the region on predicted O₃, NO₂, and NO levels within the modeling region. Pollutants transported into the region appear to have a significant influence on O₃ levels. The influence of stationary source emissions on O₃ and NO₂ levels is greater than that of mobile source emissions. The model has been a valuable tool in evaluating the possible influence of different source categories and control regulations on pollutant concentration levels.