Meteorologists say that Wednesday is likely to be the hottest day of the year with temperatures expected to reach 33C and with dangerous ozone levels also rising. Since the beginning of June ozone concentrations have regularly exceeded legal limits.
Switzerland, like the rest of Europe, has recently been enjoying tropical weather. The first half of 2006 has been exceptionally warm, with temperatures up four degrees on average. Even so, the Swiss meteorological office says that this year's summer heatwave is unlikely to beat that of 2003, when thermometers hovered around 30C for several months.
However, for the past six weeks ozone levels in parts of Switzerland have regularly surpassed the legal limit of 120 micrograms per cubic metre (µg/m³).
By early Wednesday afternoon 11 of the 16 stations that belong to the National Air Pollution Monitoring Network recorded measurements above the 120 µg/m³ limit. Exceptional highs were recorded in Lugano (214 µg/m³) and Basel-Binningen (202 µg/m³).
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http://www.swissinfo.org/eng/front/detail/Switzerland_swelters_under_heatwave.html?siteSect=105&sid=6906610&cKey=1153317410000