Diurnal and seasonal variations of surface ozone in a Mediterranean coastal site, Patras, Greece

Ozone was continuously monitored in Patras from March 1992 until August 1993. Mid-day maxima occurred at 14:00 h in the winter and at 16:00–17:00 h in the summer. A night maximum was always observed from 00:00 h until 05:00 h in the summer and from 21:00 h until 05:00 h in the winter. August was the peak month. Throughout the summer and frequently in the other seasons, the maximum hourly value exceeded 90 ppb, the new European Union standard. The observed maximum day values were not correlated with any particular wind direction.