Heatwave raises new demands for European approach to ozone smog

The high summer temperatures are leading to potentially harmful ground-level ozone concentrations in several Member States, giving rise to new calls for a stricter EU policy on air pollution.

The exceptionally warm August of 2003 is putting the ground level ozone issue back on the political agenda. In several countries, levels of over 200 microgrammes per cubic metre ozone concentration were measured in recent days. In France, the authorities of Paris, Strasbourg and Lyon took emergency measures to reduce speed limits or cut bus fares to promote public transport. In Germany, several environmental organisations called for similar emergency measures, but Green Environment Minister Jürgen Trittin refused to introduce driving restrictions as these would not solve the problems in the short run.

Most national authorities pointed to the fact that the ozone smog is a transboundary problem with winds driving the ozone pollution across borders.


Ground-level ozone (or ambient ozone) is a form of air pollution which occurs in the summer when nitrogen oxides and volatile organic compounds or VOCs ("precursors" of ozone) start a photochemical process as a result of high temperatures and heavy sunlight. High concentrations of ozone can cause serious health problems for certain population groups (children, people with respiratory problems, elderly persons) and can lead to damage to ecosystems, agricultural crops and materials.

In 1992, the European Union adopted Directive 92/72/EEC on air pollution by ozone ("the ozone directive"). The directive came into force in March 1994. It set up procedures to monitor ozone concentrations, exchange information, alert the population if certain tresholds are exceeded and to optimise the action needed to reduce ozone formation.

In 2002, a new Directive 2002/3/EC relating to ozone in ambient air strengthened the EU's policy. This Directive 2002/3/EC, also known as the third daughter directive to the Air Quality Framework Directive 96/62/EC, set long-term objectives, target values, an alert threshold and an information threshold for ozone.

The current Directive 92/72/EEC will be repealed from 9 September 2003. By that date, Member States have to comply with Directive 2002/3/EC. The Directive foresees that governments have to set in train action plans when the alert level of 240 microgrammes/m3 is exceeded.

In October 2002, the European Environment Agency (EEA) reported that, during the summer of 2002, health treshold levels were exceeded somewhere in Europe on more than three days out of four.


  • The new Directive 2002/3/EC will replace the current legislation from 9 September 2003;
  • By 31 December 2004, the Commission will have to submit to the European Parliament and the Council a report on the application of Directive 2002/3/EC;
  • The EU's approach to ozone smog is part of a future thematic strategy on air pollution, promised under the 6th Environmental Action Programme, and expected to be adopted by mid-2005.



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