Beurteilungswerte für ozon zum schutz der vegetation

Tropospheric ozone poses a critical threat for human health as well as for vegetation. In the context of the Convention on Long-Range Transboundary Air Pollution (LRTAP) concentration-based and stomatal flux-based critical levels for vegetation were defined above which direct adverse effects on sensitive vegetation may occur according to present knowledge. While concentration-based critical levels are suitable for estimating the risk of damage only, flux-based critical levels and the associated response functions could be used for assessing economic losses. If the flux-based critical levels are exceeded the corresponding receptor is at risk. In accordance with the meaning of Article 2 of the European Council Directive 2008/50/EC for wheat a target value is suggested by the working group NA 134-03-03-02 "Effects of Air Pollutants on Vegetation" of the Commission on Air Pollution Prevention of VDI and DIN - Standards Committee KRdL. Relative yield losses should be related to this target value and the use of a three colour scale (traffic lights) is recommended to indicate and communicate the degree of risk for ozone damage.