LONDON - People living in southern and central England were warned on Wednesday to stay indoors and avoid afternoon exercise for the next three days as the heatwave triggered a dangerous summer smog.
The Department of the Environment said the smog -- caused by heat and sunlight acting on air pollution to produce atmospheric ozone -- would last until Saturday when more changeable weather is expected to return.
"People sensitive to air pollution ... should be aware of the heightened risk to their health so they can take sensible precautions such as avoiding exertion outdoors on hot afternoons," junior environment minister Ben Bradshaw said.
Temperatures in southern England hit 33 degrees Centigrade on Sunday and are expected to remain above 30 until at least Friday.
People particularly at risk from the resulting summer smog are asthma sufferers and those with heart and lung disease, the department said.
Ozone on the upper atmosphere protects the planet from ultraviolet rays from the sun. But in the lower atmosphere it becomes a pollutant.
The main reason it is produced in the lower atmosphere is the reaction of heat and strong sunlight on car exhaust fumes and other pollutants.
The Department of the Environment said 800 people in Britain may have been killed by air pollution in the heatwave of 2003 which killed thousands of people in southern Europe.
REUTERS NEWS SERVICE
