Case study

Sarah Fulford-Brown, 45, moved to Lytham St Annes in Lancashire from central London eight years ago. Two of her three children had serious asthma, particularly her daughter Georgina, who was four at the time. Now, away from the pollution of the capital, both Georgina and her younger brother Benedict have made full recoveries.

Mrs Fulford-Brown said: "We used to live just off Notting Hill Gate, and the pollution there was so bad that somebody once told me they had given up trying to record the carbon monoxide figures. Georgina was diagnosed with asthma very early and put on a lot of medication, including two different kinds of nebuliser and various other inhalers. Over the next three years, she was admitted to hospital six times with serious asthma attacks. It was absolutely terrifying.

"Since we moved to Lytham, there has been an absolute improvement. She's a good runner and her school hockey team, of which she is an integral part, has recently won the Lancashire title. She still takes her [inhaler] to training but never uses it. I guess you could say she's a good advert for country living."

Mrs Fulford-Brown was angry that the link between exhaust fumes and asthma had not been established before. "I think that a lot of information has been hidden. There is still no easy solution but at least this knowledge is a big step in the right direction."