More effort needed to reduce summer ozone

"In summer 2011, exceedances of ozone targets were lower than average," EEA Executive Director Jacqueline McGlade said. "But it is still one of the most serious air pollutants in Europe. Air pollution affects people’s quality of life."

Ozone can cause respiratory problems and other severe health problems.

Ground level ozone production depends on weather conditions such as solar intensity and temperature, and is a result of chemical reactions between other pollutants in the air. These include nitrogen oxides, carbon monoxide, methane and non-methane volatile organic compounds. These substances are emitted by industry, transport, agriculture and other sources.

The European Environment Agency (EEA) publishes an annual report on summer ozone levels. The 2012 report, covering April to September 2011, was based on data from 2 186 monitoring sites across Europe.

Main findings of the report

• In the summer of 2011, the ‘information threshold’ and the ‘long term objective’ (LTO) for the protection of human health were both exceeded in the lowest proportion of air monitoring stations since the start of comprehensive Europe-wide data reporting in 1997. This reduction was mainly due to unusually low temperatures and increased rainfall during the summer months, although there have also been some reductions in the emissions of ozone-precursor pollutants.

• The information threshold (a one-hour ozone concentration of 180 μg/m³) was exceeded at monitoring sites in 16 EU Member States and four non-member countries. The information threshold was exceeded at approximately 18 % of all operational stations. Only northern Italy and several more isolated locations reported a substantial number of exceedances.

• As in previous years, the LTO for the protection of human health (maximum daily eight-hour mean concentration of 120 μg/m³) was exceeded in all EU Member States. These exceedances were registered at approximately 84 % of all operational stations. This limit was exceeded on more than 25 days in a significant part of Europe.

• The alert threshold (a one-hour average ozone concentration of 240 μg/m³) was exceeded 41 times. Concentrations of 300 µg/m³ or more were measured three times in 2011, in Bulgaria, Italy and Spain.

Ozone pollution – not only a local air quality issue

In Europe, ozone concentrations in a particular country are also influenced by emissions in other northern hemisphere countries and by sectors such as international shipping and aviation. Thus, ozone pollution is not only a local air quality issue but also a hemispheric and global problem.

Data sources on emissions of ozone precursor gases

The EEA ground-level ozone viewer provides interactive access to provisional unvalidated ozone data in near real-time. Moreover, the Agency recently published preliminary emissions data on the air pollutants that contribute to the formation of ground-level ozone.

The EEA website includes a table of exceedences across Europe in 2011.