Air quality in major Portuguese urban agglomerations

This paper presents some recent research work that has been developed for the major Portuguese agglomerations. Three main topics are developed: the methodology used in Portugal to limit agglomerations (as they are defined by the European Air Quality Framework Directive 96/62/EC), the preliminary assessment of the air quality levels in the most densely populated agglomerations over the last five years and their influence on the air quality levels across the country (a requirement by Directive 96/62/EC), and the use of an air quality index to raise public awareness about air quality levels. It is concluded that particulate matter is the critical pollutant in Portuguese populated urban areas. In Lisbon and Oporto, based in 1999 data, in all monitoring stations, the daily average limit value of 50 mug m(-3) for particulate matter (PM10) is exceeded more times during a year period then allowed by Directive 99/30/EC. In the same areas, nitrogen dioxide concentrations are above the annual limit value of 40 mug m(-3) for the protection of human health set by Directive 99/30/EC, and influence pollution concentrations within a few tens of kilometres surrounding the urban areas.