DEVELOPMENT OF METHODOLOGIES TO ESTIMATE THE IMPACT OF OZONE ON VEGETATION

Environment in Northern Ireland for funding provided under contract No. EPG 1/3/104. The research has also been supported by funding from the Nordic Council of Ministers (NMR). The time spent by Dr. David Simpson and Dr. Juha-Pekka Tuovinen on the project was supported from the programmes of their own institutes (EMEP and Finnish Meteorological Institute respectively) on ozone deposition. 2EXECUTIVE SUMMARY · Ozone deposition to land surfaces across Europe depends to a large extent on the uptake of the pollutant through the stomata of surface vegetation. Surface deposition processes are an important component of the pan-European EMEP photochemical model that is currently used in risk assessment of ozone impacts and in assessing the impact of different ozone precursor control strategies within UN/ECE. · The impacts of ozone on vegetation are more closely related to ozone flux through the stomata than to external concentrations. Therefore, a methodology based on predictions by the EMEP model of ozone flux, rather than the current AOT40 index, may provide a sounder basis for risk assessment of ozone impacts on vegetation across Europe