Air pollution in Barcelona

An air pollution episode occurs when levels of atmospheric pollutants exceed the threshold values established by the European Union (EU) and become harmful to people's health. It can occur as many as three times a year in Barcelona, especially when it comes to suspended PM₁₀ particles (80 µg/m³ or 50 µg/m³ for more than 3 consecutive days) and nitrogen dioxide NO₂ (200 µg/m³ or more)

The Generalitat of Catalonia may declare alert for high environmental pollution in two phases, "Preventive warning" or "Environmental pollution episode", depending on concentration level of contaminants and according to the pollutant: PM₁₀ and NO₂. Alerts with both pollutants at the same time may occur.