Pollution nears 'danger' levels

Pollution could reach critical levels this summer as temperatures remain high and wind levels drop, experts fear.

High amounts of smog mean children, asthma sufferers and people with heart problems are particularly at risk.

' The air is just sitting there, not moving, which means there is nothing to take the pollution away,' said forecaster Jim Galvin.

Last year, levels of ozone - which irritates the lining of the lungs - were at their highest since records began.

Smog, caused by sunlight reacting with airborne pollutants such as ozone, is found in big cities around the globe.

The World Bank predicts that 500,000 premature deaths each year are caused by air pollution.

During the summer months in Tokyo, a thick, yellow smog hovers above the city and contains high levels of sulphur dioxide and nitrogen dioxide.

The Department for the Environment, Food and Rural Affairs has now issued a warning to Britain's city-dwellers, especially those suffering from lung or heart problems.'Those affected should avoid making car journeys and exercising outdoors in the afternoon,' said a Defra spokesman.

'During episodes of air pollution experienced during the summer in the United Kingdom, levels of ozone, nitrogen dioxide and particles may be raised.

'Most people will experience no illeffects but those suffering from lung diseases, including asthma, should be aware that their symptoms might worsen - particularly if they are elderly.'

The Liberal Democrats claim that, at present levels, smog could cause up to 100,000 deaths in the next 20 years.

However, pollution was far worse in years gone by.

The London smogs of 1948, 1952 and 1956 killed an estimated 22,000 people.

The deaths prompted the introduction of the Clean Air Act of 1956.

This served to clean up the atmosphere by imposing smoke control areas, increasing the height of chimneys and prohibiting emissions of dark smoke.