Table 1

(^a) AOT40 is an indication of accumulated ozone exposure, expressed in micrograms per cubic metre (μg/m³) per hour, over a threshold of 40 parts per billion (ppb). It is the sum of the difference between hourly concentrations of >80μg/m³ (40ppb) and 80μg/m³ accumulated over all hourly values measured between 08:00 and 20:00 (Central European Time).

(^b) In the context of this briefing, only yearly AOT40 values, called thresholds, are considered, while five-year averages are not.