The north-eastern city topped the list with 104 days over the recommended ozone limit during 2011, according to a report released on Tuesday. The EEA target is for 25 days a year, averaged over three years, to avoid breathing problems.
Nine of the top 10 ozone-polluted cities were in Italy. Lecco in northern Italy came second, with 100 days over the limit, followed by the Spanish city of Cáceres. The top 10 also featured Verona, Parma and Modena.
Rome fared relatively well, with 24.2 days over the recommended ozone limit. Turin was just over the limit with 31 days, while Milan still has work to do with 59 ozone-filled days.
Outside of Italy, Parisians breathed easily with just 10.3 days over the limit, while Berlin saw 15 days of high ozone levels and Madrid 17.8.
Across Europe, up to 98 percent of city dwellers were exposed to ozone levels above the recommended level, the EEA said.