The levels of ozone in the air are expected to surpass the European information threshold in central and northeastern Belgium on Saturday.
Belgium's interregional Environment Unit (Celine), reported elevated ozone concentrations on Friday across air quality monitoring networks in all regions of the country.
In Flanders, measurements exceeded the European information threshold of 180 micrograms per cubic metre at four locations, with a peak of 208 µg/m3 recorded in Schoten.
Brussels reached a maximum of 163 µg/m3, while Wallonia recorded 175 µg/m3 in Engis.
Despite the high levels, Friday’s concentrations were slightly lower than forecasted, according to Celine.
On Saturday, a combination of air pollution, warm temperatures and sunny weather is expected to cause a sharp rise in ozone levels, leading to further exceedances of the European threshold in central and northeastern regions of the country.
By Sunday, cooler temperatures are expected to reduce ozone levels to normal in western Belgium.
However, elevated concentrations will persist in the eastern and southern regions, though no further threshold exceedances are anticipated.
The European information threshold of 180 µg/m3 is the level at which the public must be notified, while the alert threshold stands at 240 µg/m3.
