Smog levels exceed health limits in Oxfordshire

Research analysed by the charity showed the city was among five official sites, where monitored pollution levels soared to more than double the national health limit for six consecutive days.

The other four were Bournemouth, south Oxfordshire, Cambridgeshire and Devon.

The Government's "Air Quality Strategy for England, Scotland, Wales and Northern Ireland" published in 2000, set the health standard for ozone at 100 microgrammes per cubic metre.

A level of 218 microgrammes was recorded in the city on Saturday.

Friends of the Earth's Pollution campaigner, Tony Bosworth said: "Our record-breaking sunshine has brought a lot of smog, breaching health standards nationwide.

"And because of the way ozone pollution travels, people who tried to escape the heat of our cities for a breath of fresh air will have found they got just the opposite."

Smog levels are monitored at 80 sites across the UK.

Asthmatics warned

Smog is the result of strong sunlight reacting with pollutants created mainly by vehicle exhausts which combine to create ground level ozone.

The new figures, follow a warning issued to asthmatics in April about the current heatwave, which advised them to carry their inhalers at all times.

Choking, headaches and irritation to the eyes, nose and throat are just some of the health problems people can suffer as a result of high ozone levels, according to the charity.

Mr Bosworth added: "The Government must do more to tackle the source of the pollution by cutting the amount of traffic on our roads.