The Department of Territory, Housing and Ecological Transition of the Generalitat de Catalunya and the Barcelona Supercomputing Center - Centro Nacional de Supercomputación (BSC-CNS) have promoted a new key tool for predicting and managing air quality. This is CALIOPE-Urban, an innovative system capable of forecasting the concentration of nitrogen dioxide (NO₂) at street level in the city of Barcelona, with a resolution of up to 20 meters and 24 or 48 hours in advance. The tool, developed by BSC and funded by the Catalan government, is a new phase of the CALIOPE modelling system for air quality forecasts for the Iberian Peninsula, Catalonia and the city of Barcelona.

The data, now openly available on the CALIOPE portal, will allow administrations, the research community and the general public to access hourly forecasts of the concentration of NO2, one of the main air pollutants, mainly from road traffic. This information will be essential for designing more effective policies for public health protection, mobility and urban planning. It should be noted that air quality forecasting makes it possible, for example, to identify pollution episodes, model future air quality scenarios or assess the effectiveness of reduction measures.

The system uses the power of the MareNostrum 5 supercomputer to combine meteorological, emission and pollutant dispersion models with urban data and artificial intelligence methods. The result is highly accurate simulations that identify pollution hotspots and evaluate the effectiveness of measures such as low emission zones (LEZs) or traffic restrictions. For now, the system is focused on the city of Barcelona, also encompassing areas of other municipalities such as Hospitalet de Llobregat and Badalona, but work is underway to replicate the methodology in other cities or metropolitan areas in the future.

New European air quality directive

With CALIOPE-Urban, Catalonia, and Barcelona conurbation in particular, is at the forefront of European areas that integrate science and technology into environmental management. This new phase of CALIOPE comes at a key moment marked by the new requirements of the European air quality directive, which sets stricter targets for 2030 for reducing air pollution, considered by the World Health Organization (WHO) to be the main environmental risk factor for health worldwide.

The public administration of the future must integrate the technical tools available to improve air pollution management. Therefore, in the words of the General Director of Climate Change and Environmental Quality of the Generalitat, Sonsoles Letang, “our will is to promote these scientific developments that, together with the Network of Monitoring and Forecasting of Air Pollution, which we manage from the Department of Territory, Housing and Ecological Transition, allow the availability of information on air quality throughout the territory, forecast pollution episodes and determine what actions are efficient to improve air quality and preserve the health of our citizens.”

“The use of models such as CALIOPE allows us to create a digital twin of air quality, so we can better understand past events and their causes, predict what will happen in the coming days and, based on this information, take measures such as declaring high pollution episodes, as well as test and define strategies to improve air quality before implementing them,” said Albert Soret, leader of the BSC's Earth System Services group.

CALIOPE is the only air quality forecasting system that provides operational forecasts for Barcelona (up to 20 m x 20 m), Catalonia (1 km x 1 km) and the Iberian Peninsula (4 km x 4 km), and is the only Spanish contribution to the European Union's Copernicus Atmosphere Monitoring Service (CAMS).