Pollution 'takes a year off your life'

AIR pollution costs city-dwellers a year of their lives, scientists have concluded after the biggest and most thorough study ever conducted into the causes of premature death.

Authors of the study, which traced the fate of more than 500,000 people in 151 metropolitan areas in the US, say that air pollution at levels typically found in British cities reduces life expectancy by a year.

British scientists estimate that the pollution - caused by tiny particles of fuel emitted from chimneys and motor vehicle exhausts - also kills thousands of people in this country each year.

But the particles - less than 10 microns (one-tenth of the width of a human hair) in diameter - are neither regulated nor widely measured in this country.

The Government's official advisers, the Expert Panel on Air Quality, has only just recommended a standard for the maximum pollution to be permitted in the air, and this has not yet been published. Even when it is made public there is no guarantee that it will be implemented: earlier this year the Environment Secretary, John Gummer, refused to adopt the panel's recommended standard for ozone, one of the pollutants that does most to exacerbate the asthma epidemic that now affects one in every seven British children.

The giant US study is remarkable for its size and the thoroughness with which it has screened out other possible causes of death, such as smoking, alcohol and obesity. It concludes that death rates in the cities most polluted by the particles, such as Los Angeles and Salt Lake City, are 15 to 17 per cent higher than in the cleanest ones. Deaths from respiratory and heart diseases are particularly high.

But life expectancy is shortened even in moderately polluted cities, such as Washington DC. Dr Douglas Dockery of the Harvard School of Public Health, an author of the study, reckons that long-term residents of such cities lose a year of life expectancy compared with those who live in the cleanest areas. Another author, Dr Michael Thun of the American Cancer Society, stresses that this is Dr Dockery's own calculation but adds: "In scale, it is right."

Britain began measuring this pollution only three years ago, and has 16 stations monitoring it. But the figures gathered so far suggest that levels of the pollution in British cities from Cardiff to Liverpoool and London to Belfast are much the same as in Washington.

British experts say that US findings cannot be automatically transposed overseas. A study into the death toll in this country is being carried out in Birmingham, and should be published later this year.

In the meantime the experts accept that the particles are much the most dangerous form of air pollution, and estimate that they kill at least 10,000 Britons every year.