Abstract
The paper deals with emissions and dispersion of pollutants caused by vehicles in urban areas. Special attention is paid to dispersion of pollutants caused by cold start of an engine. Mathematical and numerical models which enable us to define the concentration of pollution are presented in the paper. The numerical model is based on the finite volume method. Each vehicle is treated as a movable point source of emission. Changeable velocity and different directions of wind are taken into account. Results of computer simulations obtained for different emission models (COOPERT, INRETS) are compared. The results presented enable us to estimate the concentration of various pollutants and observe changes taking place in the impurity cloud over time.