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The modelling system has been initially built starting from the experience of FUMAPEX research project (2002-2005), funded by the 5th Framework Programme of the European Commission, where ARIANET and ARPA Piemonte set up a prototype forecast system over Piemonte and Turin, and of the MINNI project (2002-present), the national integrated model to to support national planning and the international negotiation on atmospheric pollution, set up by ENEA and ARIANET on behalf of the Italian Ministry for the Environment, Land and Sea.

Then, it has been enriched also within the COST Action ES0602 collaboration framework.

Available referance:

J. Kukkonen (2012)."A review of operational, regional-scale, chemical weather forecasting models in Europe" ATMOSPHERIC CHEMISTRY AND PHYSICS

System milestones

Modelling system


QualeAria main purpose is to forecast regional scale air pollution over the Italian peninsula. This is performed on the basis of the description of the emissions and the weather forecast over the area, but also requires representation of the contributions from surrounding areas. To achieve that, meteorological and air quality simulations are performed with the nested domains technique, allowing a proper descriptions of phenomena at the implied space and time scales while limiting the computational resources. So the Italian domain is nested in a wider background one, including a large fraction of continental Europe and the Mediterranean Sea, properly fed by continental emission inventories, synoptic scale weather forecasts and global scale air quality forecasts.



QualeAria is largely based on ARIA Regional components, with the connections and main data sources depicted in the following figure.


  • a prognostic meteorological model RAMS provides the downscaling of synoptic weather forecast on the computational domains of interest;
  • dispersion, chemical transformations and deposition of atmospheric pollutants are described with FARM chemical-transport model;
  • a meteorological interface module GAP+SurfPRO matches the standard output fields produced by the meteorological driver with the needs of FARM CTM (grid adaptations, diffusion parameters, deposition velocities, etc.);
  • an emission processor EMMA prepares gridded hourly emissions of all the pollutants considered by FARM CTM starting from national and continental inventories;
  • pre-processors prepare the hourly BC for the FARM background domain, starting from large-scale air quality forecast;
  • finally, post-processing modules compute air quality indicators, verify possible air quality standards exceedances and produce plots and tailored data (e.g. BC for regional air quality forecasting systems), allowing to disseminate the results to stakeholders and the general public.

QualeAria is capable to forecast concentrations of all pollutants covered by EU and Italian air quality directives (among the others: SO2, NO2, CO, PM10, O3 and benzene).

The air quality forecast is presently provided for the current day and up to 120 hours.

The current configuration of a few relevant components is described in the following.

Emissions treatment

Anthropogenic emissions over the two computational domains are assigned starting from different data sources:

Gridded hourly emissions are then prepared via Emission Manager processor (EMMA), performing grid disaggregation, time modulation and VOC/PM speciation.

Sources characterized as point entities are treated individually, and allocate to the grid considering the plume rise, while all other diffuse sources are spatially disaggregated using gridded proxies, prepared from digital land-use and cartographic data (e.g. CORINE Land Cover).

The following figure shows as an example a gridded field of NO emissions at 08:00 l.s.t. prepared from a national inventory of yearly NOX emissions from diffuse (provinces) and point sources, and a European inventory on a coarser grid.


The process is applied consistently to both computational domains.

Emissions from natural sources are dynamically assigned through SURFPRO:

Meteorological downscaling and pre-processing

The meteorological fields needed by the air quality forecast system are produced starting from numerical weather predictions made available by the United States meteorological service (NOAA NCEP). The meteorological fields distributed by NCEP have a spatial resolution of 1 degree and time resolution of 3 hours.

These fields are used to initialize the non-hydrostatic meteorological model RAMS, producing forecast mesoscale meteorological fields on the two nested computational grids.

The meteorological fields produced by RAMS are then transferred to the air quality grid system by the GAP interface module, performing space interpolation on the FARM CTM grids and the re-evaluation of the vertical velocity.

Finally, the meteorological processor SURFPRO is used to estimate dispersion coefficients and pollutants-specific deposition velocities.

Chemical-transport model

Atmospheric pollutants are modelled with FARM, a multiscale 3D Eulerian chemical-transport model that accounts for transport, chemical conversion and deposition.

The model can be configured with different chemical and aerosol schemes. Currently, QualeAria uses the version implementing SAPRC99 gas-phase chemical mechanism and aero3 aerosol module.

The model implements one-way and two-way on-line grid nesting. In QualeAria, FARM uses two-way nesting applied to the background European and Italian domains.

Boundary conditions for the outer domain are prepared from the global scale forecast provided daily by the ECMWF MACC-C-IFS-TM5 model as part of the Copernicus Atmosphere monitoring service and acquired through the WCS server in Jülich.

Operational chain

QualeAria is an actual application of F-Air. The procedure is automatically lounched on a daily bases and produce 120 hour forecast. The following scheme sketchs the the daily schedule time line.


Operation statistics

QualeAria is on-line since 2007, during this period both model configuration and governing procedures have been improved to reach the reliability needed for operational purposes.

The following graph shows the monthly data availability for 2013.


Model evaluation

On a regular bases, QualeAria performance is evaluated using the BRACE database has reference.





From Global to Local

The importance of the potential application of QualeAria as a starting point for regional modelling is highlighted here in term of creating on operational basis, a "bridge" between local accurate information and expertise and regional to global information.


Significant improvement of the air quality forecast comes both from using high resolution emissions, clearly affecting pollutants more influenced by local factors such as PM10,


and considering long range processes, which drive for example the formation tropospheric Ozone.


IC/BC for regional/local forecast systems

The QualeAria forecast fields (meterorology and air quality) operationally provide background information that can be used to initialize/constrain regional and local forecast systems running at finer scales.

The configurable post-processing chain allows to extracts an regrid subsets of the desired data over areas of interest, and make them available via FTP transfer.


At the present QualeAria is distributed on a daily bases as IC&BC for the systems of Arpa Lazio, Arpa Friuli Venezia Giulia, the project AriaSana for the city of Naples, Arpa Molise, Arpa Puglia and Arpa Valle D'Aosta.

Historical archives

The 3D meteorological and air quality fields produced daily by QualeAria since year 2009 are progressively archived.

On request, from the resulting historical archives can be extracted: