Under a 1992 directive on ozone pollution, EU countries have to communicate to the Commission within a month all breaches of the 180ug/m3 level. Each autumn, the Commission analyses trends in summer ozone pollution, when high levels are most likely to occur due to photochemical reactions involving precursor chemicals such as nitrogen oxides and volatile organic compounds.
France was the only country not to supply any data, despite Paris and other major cities having experienced serious ozone pollution episodes this summer (ENDS Daily 25 August). A Commission official told ENDS Daily that this was an infringement of EU law and that the Commission was questioning the French authorities.
Of the 14 countries that did supply information, only Finland, Ireland, Denmark and Sweden reported no breaches of the 180ug/m3 threshold, which is measured over one hour. In the other ten countries, the number of days on which ozone levels passed the threshold between April and August ranged from 5 in Luxembourg to 49 in Italy.
The directive's highest ozone warning threshold of 360ug/m3 was breached once in Athens, but nowhere else in summer 1997, according to the figures. However, a Commission official told ENDS Daily that ozone levels well above the threshold had also been measured in Siracusa in southern Italy, but were not included in the report.
The number of stations reporting ozone levels over 180ug/m3, the frequency of exceedences at those stations and maximum ozone concentrations were all lower this summer than in 1996 and 1995. However, according to the Commission, this was not due to reduced emissions of ozone precursors but to less favourable weather conditions for high ozone levels in 1997. The only exception this summer was in August, when more than two-thirds of the season's breaches of the lower threshold occurred.
European Commission, tel: +32 2 295 1111.
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