Saturday may see the European ozone information threshold exceeded, according to the Interregional Environment Agency (IRCEL) on Friday.
Due to warm and sunny weather, coupled with weak winds and air pollution, local excesses are expected on Saturday.
This indicates that in some areas, more than 180 micrograms of ozone per cubic metre may be measured.
According to European regulations, the public must be informed of such occurrences.
People who are particularly sensitive to air pollution, such as children, the elderly, or those with respiratory issues, are advised to avoid unusual physical exertion outdoors between 12:00 and 22:00.
Ozone concentrations indoors average about half those found outside.
Previously, IRCEL had suggested that there would be no excesses, but recent forecasts have shown different results.
However, an exceedance of the alarm threshold of 240 micrograms per cubic metre, which would trigger recommendations for the entire population, is still not expected.
