Belgium experiences winter smogs on a regular basis. Smogs can adversely affect our health. They are caused by the accumulation of car exhaust pollutants, industrial activity and emissions from domestic and office central heating systems. Smogs occur between the months of October and March, when weather conditions, such as low temperatures, lack of wind and above all the phenomenon of thermal inversion (when lower layers of air are cooler than upper layers), prevent the dispersion of pollution in the air. This results in a general reduction in air quality which may have an adverse effect on those of delicate health, and also on the entire population. Smogs may last for a few hours or several days.
Do not confuse smog with the ozone peaks that occur in summer.
Emergency measures must be taken to avoid these smogs. These measures are aimed at reducing the emission of pollutants (48 hours in advance) so that the expected peak is not reached. There are 3 levels of intervention depending on the duration and intensity of the smog:
Level 1: speed restriction of 50 km/h (or less if indicated) applicable to all vehicles throughout the Brussels city region
Level 2 : ban on cars with even or odd number plates throughout the Brussels city region; ban on heavy goods vehicles during rush hours; underground trains, trams and buses are free and additional services are provided
Level 3 : Level 3: total ban on cars throughout the Brussels city region; underground trains, trams and buses are free and additional services are provided
Although level 1 threshold is reached 2 to 3 times per year, thresholds 2 and 3 are much less common (level 2 is reached only once every 2 or 3 years).
Whether you are an individual or an enterprise, you will be adversely affected by a deterioration in air quality, especially when smog occurs. But you also play a crucial role when it comes to reducing or even avoiding smog.
Emergency measures are intended to deal with isolated events and are not designed to structurally improve air quality. The best way to combat smog is to modify our behaviour throughout the whole year.