The territory is divided into areas according to the dispersion conditions and emissions of air pollutants.

These maps consist of a grid of 500x500m squares which set the theorical maximum concentration of pollutant (according to the current situation) still to be allowed in that area, so that the overall concentration of pollutant equals the limit permited by law. In this case, the pollutant is carbon monoxide (CO). These maps should be taken as a technical reference document only as it is still waiting to be aproved by the Catalan Government.