One in ten deaths from lung cancer in the UK may be linked to air pollution, an expert has said.

The finding adds to growing concerns that the threat to public health posed by air pollution may have been overlooked as many scientists chose to focus on smoking instead.

Professor Roy Harrison, a member of two UK government advisory committees on air pollution, said US research had provided strong evidence that fine particles contained in emissions from vehicles and industry caused cancer.

One study by the American Cancer Society found that death rates from lung cancer increased 6% for every additional 10 microgrammes of fine particles in a cubic metre of air.

Professor Harrison said that based on the Americn study, it was possible that fine particles could cause as many as 3,910 deaths from lung cancer in the UK each year.

However, he warned that the figures may be too high. He said it was difficult to estimate the true effect because cancer may develop only years after exposure to air pollution.

Writing in the journal, Ends Report, Professor Harrison said: "We know that particulate matter itself can damage strands of DNA."

Public health focus

Meanwhile, Professor Virginia Berridge, of the London School of Hygiene and Tropical Medicine, has alleged that the UK government concealed the threat to public health posed by air pollution when its effects began to become apparent following the great London smog 50 years ago.

Professor Berridge, speaking at a conference to commemorate the smog, which is estimated to have killed 12,000 people, said ministers chose instead to focus on smoking.

Thus they were able to shift responsibility to the individual, rather than face up to the political challenges of combatting pollution.

Professor Berridge said that in 1957 the Medical Research Council was planning to issue a statement in which it estimated that air pollution could be responsible for up to 30% of cases of lung cancer.

However, she claimed that a cabinet committee, fearful of political embarrassment, ased the MRC to reconsider.

As a result, a modified version was published, stating that although it was likely that air pollution did play a role in lung cancer, it was a relatively minor one in comparison with cigarette smoking.