EFFECT OF SURFACE OZONE EXPOSURE ON VEGETATION IN THE GREATER AREA OF VOLOS, GREECE

The critical level of air pollutants in the atmosphere is the concentration above which adverse effects occur on sensitive receptors, such as plants and ecosystems. Ozone is the most important air pollutant in Europe affecting vegetation and forest ecosystems and its increase in the last decades is significant. The current European critical levels of ozone for the protection of crops, natural and semi-natural vegetation and forest trees are based on exposure-response relationships using the AOT40 exposure index. The results described in this work are derived from an analysis, concerning the 7-year period (2001-2007), of hourly surface ozone concentrations recorded in the urban area of Volos, a medium-sized Greek coastal city. The analysis showed a strong seasonal variation. Some differences between the warm and the cold periods mean diurnal patterns were also noticed. The main objective of this work is to study the typical behaviour of this air pollutant concerning on the relation between AOT40 exposure index levels and reductions in horticultural crop production, at the rural area of Volos for a 7-year period started in 2001