Estimation of Ozone Concentration in a Valley of the Alps Mountains Based on Bel-W3 Tobacco Leaf Injury

The level and distribution of tropospheric ozone in remote and wildness areas of the Maurienne valley, a main axis in European transport, were determined during summertime 2004 and 2005. A comprehensive distribution of biological and chemical sensors based on the commonly used ozone sensitive Bel-W3 tobacco and the passive sampling system, was set up. A significant positive correlation was observed between the two methods and the continuous ozone monitors set in three instrumental co-locations. Moreover, results from this air quality network showed that, within a natural pathway of mass airflow, altitude and climate induced variations in plant responsiveness to ozone. Three different ozone diurnal patterns could thus be clearly identified. Biological sensing to determine ozone levels in regional-scale air quality assessment proved to be accurate at low altitudes. However, Tobacco response was limited in harsh mountainous conditions. This was probably due to a decrease of plant sensitivity.