Ozone in Belgium : country average of AOT40ppb during growing season

AOT40ppb : accumulated excess of hourly ozone concentrations above 80 µg/m³
restricted to growing season months and between the daily period from 8 till 20 h CET (expressed in µg/m³.hours)

This is the cumulative excess above the threshold value of 80 µg/m³ , i.e. the measuring of the excess of ozone concentration over all days (May - July for crops, April till September for forests) during daylight hours above 80 µg/m³ ( = the positive difference between the hourly ozone concentration and the threshold value of 80 µg/m³) multiplied by the duration (hours). The excess is expressed in µg/m³.hours.

The value is obtained by calculating the positive surplus per 5 x 5 square kilometers daily and then averaging these results spatially over Belgium and adding them for the year.

to protect crops: accumulated during growing season (May, June and July)
to protect forests: accumulated during summer (April till September)

for spatial representation, click on AOT40