Abstract: The Operational Street Pollution Model has been widely applied in many countries to model, predict, and regulate air pollution from cars in streets. The model is accurate, very fast and simple to use and has thus gained widespread popularity.

However, in recent years a number of shortcomings have been identified. It is the aim of my Ph.D. to improve OSPM with respect to some of these shortcomings. When the model was developed the developers assumed the emissions to be homogeneously distributed from wall to wall in a street, an assumption that is clearly violated in case of wide sidewalks or biking lanes, directional asymmetric diurnal traffic variations or sloping streets. The first part of my Ph.D. has therefore focused on developing a new dispersion scheme that take these effects into account.

In the presentation I will present the original dispersion scheme in OSPM as background. Secondly I will present the newly implemented dispersion scheme that can handle inhomogeneous emission distributions. This will lastly be followed by a presentation of the challenges met along the way, and some preliminary results of model runs of the new model. Some of the future model improvements will also be discussed briefly.