Catalonia’s Ecological Transition department has issued a pre-emptive warning for high ozone levels in the Camp de Tarragona air quality zone. Levels in the rest of Catalonia are expected to remain normal, according to officials on 23 May 2026.
Ground-level ozone, also called tropospheric ozone, is an air pollutant formed when nitrogen oxides and volatile organic compounds react in sunlight. Unlike the ozone layer in the upper atmosphere, this type of ozone can harm health.
Exposure to high ozone levels can irritate the eyes, nose and throat, and may cause coughing or breathing difficulties. It can also worsen asthma or bronchitis, and prolonged exposure may affect lung function, the department said.
The European Union sets an information threshold at 180 µg/m³ over one hour, and an alert threshold at 240 µg/m³. When these levels are reached, authorities advise reducing outdoor physical activity, especially for children, older people and anyone with respiratory illness.
Residents are being told to follow air quality updates and limit outdoor activity during periods of peak solar radiation. The department shared the preventive warning on its social media channels and directed the public to more information on air quality. For broader Catalonia coverage, see our news page.