It was the logical continuation of events. While a strong heatwave has been affecting France, especially the capital, for over a week, on Monday, May 25, 2026, the Paris Police Prefecture announced in a statement that a pollution peak is likely to be reached on Tuesday, May 26. « Airparif forecasts a probable exceedance of the information and recommendation threshold set at 180 µg/m³ », the prefecture specifies. According to Airparif’s assessment criteria, air quality is deemed to be « poor ».
Pollution à l’ozone (O₃) en Île-de-France - prévision de dépassement du seuil, mise en place du dispositif d’information et de recommandation en Île-de-France.
— Préfecture de Police (@prefpolice) August 12, 2025
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Lowered Speed Limits
As temperatures rise, the formation of ozone is favored. Consequently, air quality deteriorates — which is currently the case in Île-de-France. To help reduce pollution levels, recommended speeds have been lowered across all regional roads. Highways that are usually 130 km/h are now set to 110 km/h, and it's strongly advised not to exceed 70 km/h on roads typically limited to 90 km/h and 80 km/h. If possible, the prefecture recommends opting for public transportation, biking, or walking.
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Limit outdoor physical activities
For now, the ozone pollution threshold has not yet been reached. However, it is possible that it could be the case in the coming days depending on temperature changes, in which case further measures will be taken.
When the air is polluted and temperatures are high, it is recommended by the regional health agency (ARS) to drink plenty of water, avoid outdoor physical activities that make you breathe through your mouth, and to play sports near high-traffic areas. It's also important to limit the use of polluting agents indoors (cleaning products...).cleaners, varnishes, tobacco…) and keep ventilating your space for at least ten minutes a day. If you experience breathing discomfort, please reach out to a doctor or pharmacist.