Madrid hit by mysterious ozone cloud

Short-lived pollution peak thought to have broken all records; causes remain unclear

An air of mystery surrounds a massive ozone pollution peak over several Madrid suburbs on Saturday. Ozone levels briefly reached over three times the highest alert level set in EU law, breach of which requires population warnings to be issued, marking a Spanish and almost certainly European record. A senior city environment official said that a "gigantic and uncontrolled oil or solvent spillage" was the most likely cause.

Measurements taken at six points in the Madrid region on Saturday morning found ozone concentrations of up to 1,113 micrograms per cubic metre (ug/m3). In comparison, the highest warning level set in the 1992 EU ozone pollution directive is 360 ug/m3. Not a single exceedence of this level was recorded in EU countries last summer (ENDS Daily 12 October 1999). Unusually for ozone pollution, the Madrid peak occurred before sunrise and the very high levels lasted only about six hours.

Madrid's authorities publicised the pollution peak only 24 hours after it occurred and have been accused of breaching the ozone pollution directive's requirement for a public alert if levels pass 180 ug/m3 and an official warning if they exceed 360 ug/m3. The city's mayor defended the decision saying that "issuing an alert might have alarmed the public and could have forced the postponement of the [annual Madrid] marathon," which was held on Sunday.

Follow Up:
Madrid government environment department, tel: +34 91 580 3900; Madrid city council, tel: +34 91 488 1000. See also the EU's official 1999 ozone pollution report.

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