Such a development would certainly be more than welcome in the London area, for in the South West Thames regional health authority area, which covers part of London, the incidence of asthma rose by 164 per cent. 513 between 1979 and 1991. I am bound to say that those striking statistics are borne out in my own direct experience of case work in my south London constituency of Streatham. Indeed, so impressed was I by the number of parents referring to their children's asthma condition that I carried out a survey of the incidence of asthma among pupils at local primary and secondary schools in Streatham earlier this year. Sixteen of the 22 schools responding reported an increase in asthma over the past five years. In some cases, head teachers referred to dramatic increases over that period.
I am, of course, fully aware that the medical evidence, such as it is, points to the source of asthma in allergic reactions to such materials as pollen and household dust. Nevertheless, I am bound to say that I consider it more than a coincidence that when Friends of the Earth carried out a seven-city survey of nitrogen dioxide levels in the UK in 1992 it found that the worst residential site was in Streatham—with a mean level of 58.5 parts per billion. The European Union's upper safety limit is 40 parts per billion.
That monitoring exercise was carried out in the very heart of Streatham, at St. Leonard's junction, on the A23 London to Brighton road, one of London's busiest and most congested thoroughfares. The simple fact is that road vehicles are the main contributor to air pollution in urban areas; and they are overwhelmingly the source of air pollution in London. In London, road vehicles have been estimated to contribute 75 per cent. of nitrogen dioxides —which also play a major role in ozone formation—some 95 per cent. of black smoke and virtually 100 per cent. of carbon monoxide.
