Air pollution in major cities may be more damaging to health than the radiation exposure suffered by survivors of the 1986 Chernobyl disaster, according to a report published today.
The study suggests high levels of urban air pollution cut short life expectancy more than the radiation exposure of emergency workers who were sent into the 19-mile exclusion zone around the site straight after the accident.
Two explosions at the Chernobyl reactor killed three people immediately and more than 30 died from acute radiation poisoning, but the radioactive plume released from the reactor spread over most of Europe and is estimated to have caused up to 16,000 deaths.
The latest study follows a report last month from the Royal Commission on Environmental Pollution which said air pollution was responsible for 24,000 premature deaths in Britain every year.
Sir John Lawton, chairman of the commission, said the government had consistently failed to tackle rising levels of chemicals in the atmosphere in cities.
Other findings this year showed that women living in areas of high air pollution were at greater risk of heart disease and death, while children living within 500m of motorways suffered more permanent lung damage and lower life expectancy, probably because of their greater exposure to pollutants in vehicle fumes.
Jim Smith, a scientist at the government's Centre for Ecology and Hydrology in Dorchester, assessed the health risks faced by emergency workers at Chernobyl directly after the explosion and those who unofficially set up home in the exclusion zone afterwards. He compared them with the more familiar risks of air pollution, obesity, and passive and active smoking. He concluded that the Chernobyl group received doses of radiation equivalent to more than 12,000 chest x-rays and likely to cause one extra death in a hundred by increasing the risk of cancer.
The health risks associated with air pollution and passive smoking appear more severe. Pollution in central London increases mortality due to heart and lung disease by 2.8% compared with Inverness, Britain's least polluted city, while living with a smoker increases mortality by 1.7%, the study found.
In the journal BMC Public Health, Dr Smith writes: "Populations still living unofficially in the abandoned lands around Chernobyl may actually have a lower health risk from radiation than they would have if they were exposed to air pollution in a large city, such as nearby Kiev."
Dr Smith also calculated long-term mortality rates among survivors of the Hiroshima and Nagasaki bombings and compared them with obesity and active smoking. "The immediate effects of the Hiroshima and Nagasaki atomic bombs led to approximately 210,000 deaths in the two cities. However, radiation exposures experienced by the most exposed group of survivors led to an average loss of life expectancy significantly lower than that caused by severe obesity or active smoking," the report states.
Dr Smith said the aim of the report was to put health risks from radiation in context with more familiar threats. "We can all face such risks just going about our ordinary daily lives," he said.
"One of my reasons for comparing everyday risks with those of radiation contamination was the way in which contaminated Chernobyl refugees felt rejected by society. Our understandable fear of radiation needs to be placed in the context of other risks we encounter in our daily lives if we are to properly understand, and respond to, the potential impacts of any future radiation incidents."