Number of ozone days in Belgium since 1979
(ozone day : day with at least 1 exceedance of 180 µg/m³ ozone)

This is the number of days in which at least one monitoring station in Belgium registers that the EU population information threshold has been exceeded.

This indicator provides no information on the scope or the duration of the excess. The reported number of days depends in fact on the number of monitoring stations, and thus excludes any comparison between periods or regions with a different density if monitoring stations.