SIR – I read your article “Polluted air causes 200 deaths in Bradford” (T&A, April 11).

Air pollution causes 29,000 early deaths a year in Britain, stated the Committee on the Medical Effects of Air Pollution – a Government advisory committee.

Frank Kelly, professor of environmental health at King’s College, says it is a major health hazard.

Pollution particles smaller than ten micrometres can enter the lungs. The very small ones can pass into the bloodstream and damage blood vessels, contributing to cardiovascular disease.

Diesel vehicles give off higher levels of dangerous particles than petrol cars – and diesel sales have rocketed.

Prof Kelly says although people who live in cities or on main roads are most at risk, pollutants can travel many miles via winds.

The British Heart Foundation study last year showed air pollution leads to more heart attacks and worsening heart failure.

Last year, a research paper found 14 per cent of chronic childhood asthma cases are caused by traffic pollution. Pollution is thought to worsen emphysema, bronchitis and cystic fibrosis.

The WHO’s International Agency of Cancer Research last autumn declared air pollution as a carcinogen.

As well as diesel pollution, waste incinerators can give off dioxin chemicals which are proven to cause birth defects, higher infant death rates and cancer.

A Wills, Dulverton Road, Ruislip, Middlesex