With Tuesday on track to be the hottest day of the week, environmental officials warned that air quality levels could register a dip as ozone concentrations in the air pile up as a result of the heat.
The Interregional Environmental Cell (CELINE) said that air ozone levels remained in check throughout Monday, as they did not surpass European standards, which admit a maximum concentration level of 180 µg/m³.
But after the Royal Meteorological Institute (IRM) warned that inland temperatures on Tuesday are expected to go beyond the 30s "practically everywhere," CELINE warned that there was a higher risk of going over the warning threshold.
A warning threshold means poor air quality levels will particularly affect the elderly population, children and individuals with respiratory conditions.
If ozone concentration levels surpass 240 µg/m³ an alert is issued for the whole of the population.
During periods of poor air quality, residents are advised to avoid outdoor activities or sports between noon and 22:00.
The Royal Meteorological Institute has put Belgium on orange alert for the heat until Sunday at 2:00 AM. A yellow alert has been issued for western Flanders, and coastal cities are not concerned by the institute's alert.
The Brussels Times