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History AOT40forest ozone

The maps are based on the RIO-corine interpolation technique. The calculated concentrations are representative of areas with a surface area of 4x4 km2. The concentrations may locally be higher or lower. The modelled concentrations are subject to a certain degree of uncertainty. The uncertainty gains with the distance to the measuring station.

For vegetation, long-term exposure to ozone is more relevant than acute exposure. It is difficult to quantify the potential damage to plants caused by ozone pollution. In fact, ozone causes the most damage when it is taken up by the plant. The ozone concentrations in the atmosphere are, however, not a direct measure of ozone uptake in the plant. Many other parameters play a role: humidity level, soil condition, plant growth phase, etc. The European Union has defined an excess indicator for the protection of vegetation. The AOT40 for vegetation is the accumulated excess of hourly ozone concentrations above 80 μg/m³ between 8:00 and 20:00 CET (Central European Time = Universal Time (UT) + 1) in the months of May, June, July (=growth season). This indicator is designed for the protection of crops and (semi)natural vegetation. These indicators quantify only ozone exposure, i.e. not the effective ozone uptake by (and therefore damage caused to) vegetation.