Forecasting common air quality indexes
The work will be based on the Prevair system (www.prevair.org) which has currently a 50*50 km resolution. This resolution will be increased to 25*25 km to yield more meaningful results for urban agglomerations. Pollutants addressed are O3, NO2 and PM.
The product will be a methodology to forecast urban air quality and present it by means of the CITEAIR air quality index (CAQI) to provide comparable information to the public and the media. The methodology will take account of the fact that not all European cities have the necessary resources and detailed input data for a complex air quality forecast and will therefore distinguish between three levels of complexity.
Level 1: "eas" or "not well documented situations".
The methodology will be based on PRE'AIR regional outputs, observations from local air quality monitoring networks and all other data available. It is based on the development of statistical adaptation approaches allowing the "a priori" correction of regional concentrations: increment of NO2 and PM concentrations (because of dilution effects) is expected while decrement of O3 concentrations is foreseen (because of titration effect). Statistical corrections will be based on observations and correlation relationships with surrogates (population density, wind speed, local emission information...)
Level 2: "Mid-level approach" based on available emission data applicable for simple city typologies. Focus is put on primary pollutants (NO2 and PM). The use of nested modelling systems is based on rather simple concepts (Gaussian or empirical approaches). The concept should work if the topography and the dynamical conditions are not too stringent. The more accurate the emissions are the more accurate is the result. Regional CTMs outputs are used as boundary conditions.
Level 3: "Sophisticated approach" will be based on dynamic emission patterns and the chemistry. The approach will be based on high resolution CTMs or CFD (Computational Fluid Dynamics) models implemented with relevant chemical schemes. Regional CTM outputs are used as boundary conditions for the model area. The data and resources required to reach this level of sophistication will be analysed. Furthermore the performances expected from such systems will be analysed.