Hot weather brings summer smog
Levels of ozone reached their highest point of the year so far as the UK bathed in warm sunny weather last weekend.
Monitoring stations at several locations measured high levels of ozone as temperatures soared above 25 degrees Celsius in many areas.
High to moderate levels were recorded at almost every location in England and Wales where air pollution is measured.
Jon Bower, chief air quality consultant at the Government's contractors AEA Energy & Environment, said the weekend saw the first "ozone episode" of the year.
"We had high levels at several on sites on Saturday so it was very much as forecast," he told edie.
Air pollution is measured on a scale of 1 to 10, where 7-9 is high and 10 is very high.
Mr Bower said: "Pollution levels were high, about a 7, at several locations in England and Wales, and lots of other stations had moderate to high levels."
Last week Defra had issued a warning to the public that summer smog was expected over the weekend and urged people not to drive, as cars are a major source of pollutants that contribute to ground-level ozone.
Those with breathing difficulties and conditions such as asthma were warned to avoid strenuous exercise.
Experts have estimated there were between 225 and 593 additional deaths in the UK during the August 2003 heatwave as a result of high levels of ozone.
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