Anyone who has already taken a look at the captorair.org homepage may have noticed that (e.g. in Austria) the color coding of the measuring points differs between the one-hour and eight-hour mean value.
This is the result of the threshold values defined in the ozone act (OzonG) and their corresponding measuring method:
Information threshold: 180 μg/m³ (one-hour mean value)
Alarm threshold: 240 μg/m³ (one-hour mean value)
Target value: 120 μg/m³ (max. eight-hour mean value)
An ozone concentration of e.g. 125 μg/m³ is displayed yellow in the one-hour view because it does not exceed any threshold values.
In the eight-hour view, however, the same concentration is shown in red, since the target value (120 μg/m³), which is relevant for this measurement method, has been exceeded.