Evaluation of Ozone Phytotoxicity in the Greater Area of a Typical Mediterranean Small City (Volos) and in the Nearby Forest (Pelion Mt), Central Greece

摘要

Tropospheric (ground level) ozone is a widespread and highly toxic photochemical air pollutant affecting - directly and/or indirectly - not only the citizen's health but also the ornamental plants in the open spaces of the cities as well as the urbanand suburban trees and forests in the outskirts (Fumagali et. al., 2001; Inclan et al., 1999; Pehnec et al., 2003). It is produced by the photolysis of nitrogen dioxide and the photochemical degradation of hydrocarbons under sunlight. Ozone concentrations in remote rural areas of Europe range from 20 to 40 ppb and are expected to rise in the near future. It has been estimated that ozone levels in the northern hemisphere have doubled during the 20th century and are increasing by an annual rate of 0.5-2.0% (Guicherit and Roemer, 2000). Over recent decades ambient ozone has been recognized as a real threat for cultivated species and forest trees (Benton et al., 2000).