AIR-QUALITY PROGNOSIS, FOR THE IMPLEMENTATION OF ABATEMENT STRATEGIESOVER LARGE URBAN AREAS

State-of-the-art approaches for urban air-quality characterisation hav e several drawbacks due to apriori assumptions and/or due to inherent limitations of the concept utilised. For the evaluation of abatement s cenarios it is either necessary to embark on extensive monitoring camp aigns or to consistently apply numerical models for atmospheric disper sion. The 'ENVISOR' methodology applied here is a mixture of the two a pproaches. It forecasts pollutant concentrations during real episodes and assesses the impact from the construction of a new highway across a large urban domain of 100x100 km(2). Data from an extensive monitori ng network are used to identify real modelling periods and for validat ing the modelling simulations. The selected periods are aiming to the assessment of 'annual mean' or 'episodic' conditions. These periods ar e short-listed according to the abatement scenario under consideration . This approach yields accurate forecasts for the concentration of pol lutants after extensive validation tests extended over the whole domai n. It is foreseen that the impact from the highway construction will b e minimal for photochemical pollution whereas, higher impact will resu lt for inert pollutants due to additional emissions from the highway.