Monitoring and biomonitoring of surface ozone in Florence, Italy

An ambient air study was conducted in the city of Florence, Italy, in the s ummer 1996. Tropospheric ozone was continuously monitored with automatic an alyzers in three stations, two located in the urban area and one in the hil ly surroundings (Settignano). A biomonitoring campaign based on the tobacco cv. Bel-W3 plants was performed in the same area. The highest values were constantly recorded in the Settignano station. The highest 1-hour mean reco rded was 197 nl/l; the accumulated exposure over a threshold of 40 nl/l (AO T40) was well above the critical levels standards for protection of the veg etation. A consistent temporal variation was observed and July proved to be the month with the highest ozone levels. Cumulative frequency distribution of ozone maximum daily concentrations exhibited a good fitting to log-norm ality. No 'week-end' effect was observed. Biomonitoring data were in good a greement with chemico-physical ones.