Air pollution by ozone across Europe during summer 2007

Ozone levels during the summer of 2007 were among the lowest in the past decade.. The number and spatial extent of exceedances was lower than in any of the last ten summers. In contrast to the summer of 2006, no exceedances of the information threshold value (180 microgram/m3, Directive 2002/3/EC) occurred in the northern part of Europe. The highest one-hour ozone concentration of 479 microgram/m3 was observed in Italy on the island of Sicily, while the second highest level of 363 microgram/m3 was observed in Romania. High hourly ozone concentrations of between 300 and 360 microgram/m3 were reported a total of six times in France, Greece, Italy and Romania. As in all previous years, the directive's long-term objective to protect human health (maximum ozone concentration of 120 microgram/m3 over 8-hours) was extensively exceeded in the EU and other European countries. The target value for human health protection was also exceeded in a significant part of Europe. Forty five percent of the total number of exceedances of the information threshold, 39 % of exceedances of the alert threshold and 12 % of exceedances of the long-term objective were observed during a single episode from 14-21 July.