Kritische dosis-kenngrößen für ozon zum schutz der vegetation

Tropospheric ozone is considered as the most significant phy-totoxic pollutant in the atmosphere. The adverse effects of ozone concentrations on plant species and vegetation are well documented. In the context of the Convention on Long-Range Transboundary Air Pollution (CLRTAP) 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 a concentration-based approach such as AOT40 (accumulated exposure over a threshold of 40 ppb) is based on the concentration of ozone in the atmosphere, the real impact of ozone depends on the amount of the pollutant taken up through the stomata, i.e. exclusively, risk analyses based on the Phytotoxic Ozone Dose (POD) are toxicolo-gically relevant. To evaluate the ozone risk at local scale a simple data sheet was developed to calculate POD. Recommendations are derived for the future applicability of the POD approach in ozone risk assess-ments by means of an application example.