Air quality monitoring: establishing criteria for station classification

According to the Council Decision 97/101/EC on Exchange of Information, stations should be classified in relation to the type of area where they are located and according to the type of dominant emission sources influencing the air pollutant concentrations at the station. A detailed methodology was developed for the validation of the classification of Portuguese air quality monitoring stations, through objective criteria to assure a harmonised interpretation of the definitions, from region to region. In relation to the criteria for area types, best results were found for the population density within a 1 km radius in the surroundings of each station. In relation to dominant emission sources, recommended criteria are pointed out based upon several pollutants concentrations.