This is the first report of air pollution monitored in Greece’s Tripolis Plateau. We investigated ambient ozone concentrations and estimated its phytotoxicity potential based on three approaches: i) continuous instrumental monitoring at one station in the town, ii) phytodetection mapping with Bel-W3 tobacco plants in a network of 15 stations and iii) evaluation of ozone phytotoxicity by using the resistant (NC-R) and the sensitive (NC-S) white clover genotypes (the latter group was either sprayed or not sprayed with Ethylenediurea (EDU) or Azoxystrobin as ozone protectants).
The hourly ozone concentrations often exceeded 70 nmol mol-1. The average ozone concentration during the early afternoon hours (12:00-19:00) for June, July and August was 65.4 nmol mol-1. The monthly AOT40 (accumulated ozone mixing ratios over the threshold of 40 nmol mol-1) value was higher in July (9,123 nmol mol-1 h) and lower in October (2,022 nmol mol-1 h).
The Bel-W3 plants showed characteristic ozone-induced visible foliar injury symptoms at all the stations of the network, suggesting that ozone was at phytotoxic levels not only in the town, where it was measured, but also throughout the plateau.
The white clover revealed a reduction of the epigeous biomass of the NC-S by 36-57% in five harvests. The application of EDU prevented biomass reduction in the NC-S genotype, while Azoxystrobin did not offer significant protection.
These results indicate that, in rural areas of Greece, ambient ozone occurs at potentially phytotoxic levels, at least for sensitive plant species.