Ozone biomonitoring in a rural area near Viterbo, Central Italy

Ozone (O-3) biomonitoring was conducted by means of the hypersensitive toba cco cultivar Bel-W3 in the rural area of Collevalle (Central Italy) during summer 1998. Four biomonitoring sites were set at different elevations and distances from a nearby motorway. One additional biomonitoring site was est ablished in the suburbs of the nearby town of Viterbo, a location where ins trumental O-3 monitoring was continuously conducted since 1989, and phytoto xic O-3 levels are known to occur. Passive O-3 monitoring was carried out b y means of diffusive samplers. Biomonitoring with Bel-W3 tobacco showed tha t O-3 pollution occurring in ambient air at Collevalle was comparable to th at occurring at Viterbo. In situ validation against instrumental data sugge sted that Bel-W3-based O-3 biomonitoring is superior to passive sampling in terms of accuracy and sensitivity. Calibration against instrumental O-3 mo nitoring allowed to obtain the first Bel-W3 tobacco dose-response curve for the Viterbo area.