An operational model for vehicular pollution from a road network

We present a brief review of the mathematical model CAR–FMI (contaminants in the Air from a Road, by the Finnish Meteorological Institute). The model has been developed for regulatory purposes, for predicting dispersion of pollution from a road network. It consists of an emission module, treatment of the meteorological time–series, an atmospheric dispersion module, and statistical analysis of the computed time–series of concentrations. The dispersion module is based on an analytical solution of the Gaussian diffusion equation for a finite line source; the solution allows for any wind direction with respect to the road. The model also takes into account the chemical transformation of nitrogen oxides. The program is commercially available as a personal computer version in either DOS or Windows environment; using the model does not require specialist training.