All-time low in European ozone levels
Ozone levels in Europe during summer 2009 were among the lowest since comprehensive data reporting started in 1997. Eighteen EU countries reported exceeding the information threshold (ozone concentrations over 180 µg/m3), with Belgium, Greece, Italy and Portugal recording the largest number of exceedances.
The record lows in 2009 came despite average summer temperatures close to those measured in the extremely hot summer of 2003, which witnessed the highest number of exceedances in the last decade. The differing results in the two summers may be attributable to several factors because ozone formation is determined by various meteorological conditions, as well as the chemical composition of the atmosphere. It seems likely, however, that reductions in man-made ozone precursor pollutant emissions in Europe contributed significantly to the general decrease in peak ozone concentrations.
Source: EEA report “Air pollution by ozone across Europe during summer 2009” (3 March, 2010). Web link: www.eea.europa.eu/publications/