Smog alert system includes NO2, SO2 and O3.
Threshold values for alert
The population is informed if the concentration on an hourly basis exceeds the following values
Emitted a smog alert if the concentration of O3 on an hourly basis in 3 consecutive hours exceeds 240 µ g/m3.
In practice, only tærskelværien for information for ozone will be exceeded in Denmark. It happens very rarely (with years).
See also limit values.