In summer 2006, levels of ground-level ozone were high in southern Europe and north-western Europe, with widespread exceedances of the information threshold value (180 μg/m3, Directive 2002/3/EC). The frequency of these exceedances was higher than those in previous years, though not as high as in the record year 2003. The highest one-hour ozone concentration in summer 2006 (370 μg/m3) was observed in Italy. Other high hourly ozone concentrations of between 300 and 360 μg/m3 were reported in Austria, France, Italy, Portugal, Romania and Spain. The directive's long‑term objective u0097 to protect human health (maximum ozone concentration of 120 μg/m3 over 8-hours) u0097 was extensively exceeded in the EU and other European countries. In a significant part of Europe the target value to protect human health was also exceeded. During a single episode with two pronounced peaks between 17u009622 July and 25u009628 July (with a total duration of nine days) 49 % of the total number of exceedances of the information threshold, 56 % of exceedances of the alert threshold and 20 % of exceedances of long‑term objective were observed.
There has been a slight increase in the occurrence of exceedances during the summer period between the years 2004u00962006. The occurrence of exceedances in summer 2006 was the second highest in the last decade in north-western, central and eastern Europe. A wide area of the United Kingdom was affected and several exceedances occurred in the Baltic countries..