Ozone pollution in Spain reached its highest level since 2010 in summer 2026. This is according to an analysis published on 19 October by Ecologistas en Acción , based on official monitoring data from state and regional air-quality networks. It says exceptional heat, intense sunshine and widespread fires favoured the formation and accumulation of ground-level ozone (O3).
According to the organisation, the current legal target value was exceeded in 33 zones over the three-year period from 2024 to 2026. These include Andalusia, Illes Balears, Castilla-La Mancha, Castilla y León, Catalunya, Comunitat Valenciana, Extremadura and Community of Madrid. Madrid and Catalunya are singled out in particular: record highs were recorded in the Spanish capital. The compilation says the information threshold was exceeded repeatedly in Catalunya, and the alert threshold was also reached at times in the province of Barcelona . Regional authorities issued warnings and guidance during heatwaves.
Two categories are legally relevant: the long-term target value, which is assessed as a rolling three-year average, and the short-term thresholds for informing and alerting the public. Ecologistas en Acción says both levels were affected in several regions in 2026. This requires the relevant administrations to draw up short-term action plans, including traffic and emissions restrictions, and to ensure transparency and timely information about health risks.
The analysis refers to the national air-quality regulations, most recently amended by Real Decreto 34/2023 , and the relevant EU requirements. Ground-level ozone forms from nitrogen oxides and volatile organic compounds under intense sunlight. Elevated concentrations are associated with respiratory irritation, increased hospitalisation among vulnerable groups and long-term impairment of lung function.
In response, the organisation is calling for mitigation measures to be accelerated: stricter controls on nitrogen oxide and solvent emissions, regional action plans drawn up ahead of heatwaves, and vehicle fleet and urban planning that reduce ozone precursors. The report identifies specific emitters as responsible only where the data supports this. Regardless of the question of causation, the risks of recurring ozone peaks rise as heatwaves persist—placing growing pressure on municipalities and regions to implement tailored prevention and emergency plans.
Editor: Andreas M. Brucker (Article created with AI assistance).