Long-Term Air Quality Assessment: Modeling Sources Contribution and Scenarios In Ivrea And Torino Areas G. Calori & S. Finardi & A. Nanni & P. Radice & S. Riccardo & A. Bertello & F. Pavone Received: 15 January 2006 / Accepted: 17 October 2006 # Springer Science + Business Media B.V. 2007 Abstract An evaluation of the air quality based on the combined use of monitoring data, dynamic emission inventories, and three-dimensional modeling has been performed in an area in North West Italy. Yearly maps of the pollutants of most concern have been produced by means of an Eulerian modeling system, run for two nested domains. The system is based on MINERVE diagnostic meteorological model, TREFIC (TRaffic Emission Factors Improved Calculation) traffic emission module, and farm air quality regional chemical-transport model. The zooming approach has allowed to correctly reproduce local concen- trations in the small urban area in the inner domain as well as to quantify the role played by selected local sources respect to distant ones. The study of the impact of the future car fleet, pointing out the expected improvement for nitrogen oxides and the persisting problem of PM, provides a rationale for air quality governance. Keywords Air quality assessment . Eulerian modeling . Long term . Traffic emissions . Scenario analysis 1 Introduction Public administrations, among their environmental duties, have the mandate to manage air quality, including the eval- uation of the impacts of new infrastructure or envisaged policy actions. This requires an accurate knowledge of pol- lution levels over their whole own territory and the com- prehension of the role played by different sources. Air pollution modeling techniques developed during recent decades have the capability to simulate the impact of emission sources, producing spatially consistent infor- mation over the areas of interest. However, the usage of fully three-dimensional modeling systems by public admin- istrations, especially for long-term assessment studies over wide areas, fed by adequate emission inventories and meteorological information, has grown only recently. This trend is the result of multiple factors, among which worth mentioning is the improved data availability, computing power, and the increasing confidence in quantitative analyses by public administrators. Furthermore, in the European Union, the legislation now requires that yearly air quality assessments have to be based on the combined use of monitoring activities, emission inventories, and modeling. The evaluation of future scenarios, with the related compliance with air quality standards, has also to be conducted on the same basis. Within this framework falls the approach presented here, in which such a modeling system applied for an entire year is used to map the current air quality status as well as to analyze the consequences of future emission scenarios. A key feature of the system is the multi-domain nesting capability, allowing detailed study of a local situation while consistently taking into account the contributions from the larger surrounding areas. The approach is illustrated through the application to Torino province, which supported the realization of an air-quality assessment on its territory, consisting of a yearly meteorological database, a detailed picture of emissions with special attention on traffic flows reconstruction, and a dispersion modeling system. Environ Model Assess DOI 10.1007/s10666-007-9105-7 DO09105; No of Pages G. Calori (*) : S. Finardi : A. Nanni : P. Radice ARIANET, via Gilino 9, 20128 Milan, Italy e-mail: g.calori@aria-net.it S. Riccardo : A. Bertello : F. Pavone Provincia di Torino, Area Ambiente – Servizio Qualità dell’Aria, via Valeggio 5, Turin, Italy