Asthma risk to children

Children who play outdoor sport in polluted areas are up to four times more likely to develop asthma, new research suggests.

Scientists believe youngsters who run around in parks and playgrounds where the air quality is poor have a higher chance than others of suffering from breathing difficulties.

They fear the rapid breathing associated with strenuous exercise may damage the lungs - triggering asthma.Today they urged parents living in cities to check pollution levels before allowing youngsters to spend long periods exercising outdoors.

Children in Britain have the worst rates of asthma in the world, with almost one in three teenagers showing symptoms of the condition. The condition - which can be fatal - is the leading cause of hospitalisation of children in the Western world and is responsible for millions of missed school days.

The research, to be presented at a joint conference of the Royal Society of Medicine, and the National Asthma Campaign today, was carried out at University of Southern California, where investigators are carrying out a 15 year study into the effects of air pollution among 12,000 children.

Professor Rob McConnell, who led the research, said: "Children from communities with high ozone levels had between three to four times the risk of developing asthma. When people are breathing heavily, their lungs are exposed to more pollutants, and this may set off the problem."