Europe 1 with AFP 6:31 p.m., June 17, 2022

Due to the heat wave episode affecting the country, the concentration of ozone in the air is increasing in a large part of France, indicates the official bulletin Prev'air, published this Friday.

The situation should continue until Sunday and will mainly affect Île-de-France, the Paca region, Normandy and Occitania.

A classic side effect of heat episodes, the concentration of ozone in the air is clearly increasing over a large part of France, according to the official Prev'Air bulletin published this Friday, which forecasts a continuation of this pollution in the coming days. .

"Under the effect of the heat wave that the metropolis is currently experiencing, ozone concentrations have been increasing sharply for two days. These concentrations should remain high today (Friday) and in the days to come", indicates the Prev'Air platform, managed by Ineris.

Île-de-France, Paca, Normandy and Occitanie particularly concerned

Exceedances of the information and recommendation threshold for ozone (180 µg/m3 hourly average) are expected in Île-de-France, Provence-Alpes-Côte-d'Azur, Normandy and Occitanie.

These thresholds could also be exceeded in the Grand Est, Center Val-de-Loire, Pays de la Loire, Brittany, New Aquitaine, Hauts-de-France, Auvergne-Rhône-Alpes and Burgundy -Franche-Comte.

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"After maximum concentrations scheduled for this Saturday June 18, the situation should evolve positively from Sunday June 19, even if local overruns will not be excluded in Île-de-France, Provence-Alpes-Côte-d'Azur or Auvergne-Rhône-Alpes", specifies the bulletin.

Overall, on Friday, the ATMO air quality index was classified as "bad" in most major cities in France, from Paris to Marseille, via Lille, Brest, Strasbourg, Bordeaux or Nantes.

Some regions have already taken action.

Thus, motorists are called upon to reduce their speed on Friday by 10km/h in the Paris region and by 20km/h in Alsace.

These speed limits will continue on Saturday in Ile-de-France, until the end of the pollution episode, while heavy goods vehicles will be asked to bypass the region.

"Differentiated traffic" in Île-de-France

The prefect of police also announced the implementation of "differentiated traffic", in particular prohibiting the circulation of Crit'air 5 vehicles (already prohibited from 8:00 a.m. to 8:00 p.m. Monday to Friday in Paris), Crit'air 4 and Crit'air At the same time, air 3. Île-de-France Mobilités will also offer, again from Saturday and until the end of the pollution episode, an "anti-pollution package" allowing you to use almost all public transport in the region. region for 3.80 euros.

Carpooling will be free for all Ile-de-France residents without means conditions, up to two journeys per day, for journeys of less than 30 km.

Ozone is a so-called "secondary" pollutant because it is not directly released by an activity.

It results from chemical reactions, under the effect of the sun, involving pollutants present in the air, such as nitrogen oxides, emitted mainly by road traffic, and volatile organic compounds (hydrocarbons, solvents, etc.) rejected by industry.

It is an irritating gas that easily penetrates to the finest respiratory tracts.

It is especially a problem in summer, in periods of strong sunshine, if there is no wind to disperse it.

It can be transported over long distances.