Preliminary assessments by the European Environment Agency (EEA) suggest that this summer's heatwave contributed to the worst ozone pollution seen in Europe for almost a decade. The hot weather, combined with emissions of 'precursor' pollutants from traffic, industry and vegetation, led to long lasting and geographically extensive episodes of harmful ground level ozone pollution across the continent. And the EEA warned that this scenario is likely to be repeated in future hot summers until legally binding EU targets on the emission of precursor pollutants are met. The deadline for Member States to achieve a 30 per cent reduction in ozone causing pollutants is 2010. A summary of the EEA assessment was sent to EU environment ministers who met in Luxembourg on 27 October. The French delegation, supported by Spain and Greece, proposed a more systematic method of information exchange and better structures for coordinating ozone policies. Of the 31 European countries that submitted data to the EEA in 2003, 23 suffered ground level ozone pollution at concentrations well above the human health threshold of 180 microgrammes per cubic meter (µg/m3) for one or more days between April and August. Those areas of Europe that exceeded the threshold most regularly were southwest Germany, Switzerland, northern and southeastern France, Belgium, northern and central Italy and central Spain. These regions are among those with the highest emissions of ozone precursor pollutants. The only countries not to go over the 180 µg/m3 level were the Nordic countries, the Baltic States and Ireland. Unlike the stratospheric ozone layer that protects against harmful solar radiation, ground level ozone can cause serious human health problems and damage to ecosystems, crops and materials. Short term exposure to levels above the 180 µg/m3 threshold can have temporary effects on the health of children as well as adults who are particularly sensitive to ozone. Governments are required by EU law to inform the public whenever the 180 µg/m3 threshold is breached, and since September, must warn people to take precautions when ozone levels exceed 360 micrograms/m3.