The simplified model of the gas emission from cars in the city is presented. The model is based on the Pasquille relation with necessary modifications regarding diffusion in the perpendicular direction to the street axis and the emission in the upper limit of the street. The emission cars from going down the street is modelled as the series of sources located close to the street level, with the emission related to the number and size of the car engine. The emission from sources of pollution located outside the street is modelled as the system of sources of pollution located on the height of the buildings along the street. Some examples showing the influence of the wind velocity and air turbulence on the carbon monoxide concentration along the length and the height of the street are presented.