Effects of air pollutants on plants

Ozone is the most important air pollutant affecting plants in Switzerland and in many other regions of NW-Europe. Critical levels set by the UN/ECE to protect plants are exceeded over extended areas, but there is increasing evidence that selection for ozone tolerance can take place in response to intensive ozone stress. Effects of ozone, including visible injury, or long-term changes in growth, biomass allocation, yield, reproduction, competitiveness, and vitality, depend on the dose of ozone absorbed by the plant. In order to assess the ozone risk for vegetation, it is thus necessary to develop dynamic models for flux-effect relationships which take into account the modifying influence of environmental mental factors.