As a result of the warm weather on Saturday, high ozone concentrations were measured in Belgium, with the Uccle measurement network in Brussels recording levels that exceeded the European ozone concentration of 180 μg/m3.
At the Uccle measurement station in Brussels, a maximum hourly concentration of 181 μg/m3 was recorded at 20:00, surpassing the European information threshold, at which point the population must be informed of the levels recorded, according to the Interregional Environment Cell (Celine).
By 22:00, the concentration of ozone decreased slightly to 157 μg/m3. High maximum hourly concentrations were also reached in Flanders, where 177 μg/m3 was recorded in Aarschot, while in Wallonia, the highest level was 170 μg/m3, recorded at the Rixensart measuring point.
During high ozone concentrations, as a preventive measure, people who are particularly sensitive to air pollution, such as children, elderly people, people with respiratory problems, etc., should avoid unusual physical efforts and any outdoor exercise between noon and 22:00.
Being exposed to elevated levels of ozone may result in people experiencing a feeling of irritation in the eyes, nose and throat, while others may also experience respiratory or heart symptoms such as shortness of breath, chest pain, and wheezing.
The high ozone concentrations are a result of pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically reacting in the presence of sunlight.
In the coming days, temperatures will be much cooler inland (around 21-22°C) with periods of rain, while thunderstorms are expected more locally.
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This will improve the air quality and ozone concentrations will decrease to normal levels for the time of year. The cell said that "no exceedance of the ozone threshold is expected," and announced the end of the warning phase of the High Heat and Ozone Peaks Plan.