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France Records Earliest Nationwide Ozone Pollution Episode
Unusually high temperatures have produced elevated ozone levels across multiple French regions. The national air-quality forecasting system issued its first May nationwide alert on Wednesday.
May 27, 9:25 AM·1m read1 source
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France is experiencing an early nationwide rise in ozone pollution linked to a May heat wave. The national Prev'air platform issued an information report on Wednesday, May 27, 2026, stating that at least two regions have recorded elevated ozone levels for several consecutive days.
Augustin Colette, an atmospheric modeling specialist at the National Institute for Industrial Environment and Risks who leads the Prev'air system, said this is the first time the platform has issued such a report this early in the year. The forecast indicated possible exceedances of the French regulatory threshold of 180 micrograms per cubic meter in Ile-de-France, Auvergne-Rhône-Alpes, and Centre-Val de Loire.
Tuesday, May 26, the French regulatory threshold was exceeded in Ile-de-France. The European Environment Agency's "very poor" threshold of 160 micrograms per cubic meter was also exceeded that day in Auvergne-Rhône-Alpes, Hauts-de-France, Grand-Est, Provence-Alpes-Côte d'Azur, and Normandy.
Prev'air stated that a significant improvement is not expected before the weekend. Normandy, Hauts-de-France, and Grand-Est could see more localized effects.
The earliest previous nationwide ozone pollution episode recorded by Prev'air occurred on June 15 in both 2023 and 2021. The current episode therefore precedes those dates by roughly three weeks.
