May 23, 2025

Caliope: The system that predicts air pollution

Barcelona is becoming a European benchmark in environmental monitoring with the launch of Caliope, a pioneering tool developed by the Barcelona Supercomputing Center that measures and forecasts air quality with 20-meter precision and hourly updates.

This technology marks a turning point in the development of smart cities and strengthens the region’s environmental commitment, in line with initiatives such as Catalonia’s recent €1 billion investment in sustainable urban transformation.

Until now, air quality was assessed using fixed monitoring stations, which only provided data for specific points. Caliope changes that paradigm. This innovative system can detect pollution levels with unprecedented accuracy by analyzing factors such as:

  • The number and type of vehicles on each street

  • Local weather conditions

  • Building heights

  • Urban layout

The result? Striking contrasts like the intersection of Balmes and Provença, where pollution levels are high, compared to the nearby Enric Granados, which shows low pollution thanks to its reduced traffic and pedestrian-friendly design.

But Caliope’s real game-changer is its predictive capacity. Just like a weather forecast, it can anticipate pollution episodes 24 to 48 hours in advance, and even distinguish between pollutants such as PM particles and nitrogen dioxide (NO₂).

This kind of data is vital to protect vulnerable groups — like the elderly or people with respiratory issues — and to evaluate urban strategies before implementing them: What happens if a street is closed to traffic? How would air quality change if a low-emission zone is activated?

All of this is made possible by the MareNostrum 5 supercomputer, which integrates thousands of variables to simulate the chemical behavior of urban emissions.

As stated by Sonsoles Letang, Director General for Climate Change and Environmental Quality of the Government of Catalonia, this model will be key to meeting the EU’s ambitious air quality directives and is already being prepared for broader implementation across the region.

At Wegsco, we celebrate innovations like these as powerful examples of how smart technology can help build more resilient, sustainable cities. Because the future isn’t just about reducing emissions — it’s about understanding them better, anticipating them, and acting responsibly. High-quality environmental data is no longer a luxury; it’s a vital tool for urban planning, public health, and ecological transformation.