Handbook of Radon.
28. The link with smoking: misrepresentation of radon risks.
Lung cancer was an uncommon cause of death before people started smoking tobacco. It is certain that lung cancer is set to become a major cause of premature death in many Third World countries, just as a steep rise in the number of cases was noted in the 1950s in the West, and following the increased consumption of cigarettes since the 1930s.
In the UK, the annual incidence of lung cancer is now around 35,000 cases, nearly all of which prove fatal. Worldwide, premature deaths from smoking (including lung cancer) are set to rise to ten million per year within 30 years.
It is accepted that radon may be the second leading cause of lung cancer. However, what has not been clearly stated within the radon debate is that whilst ALL tobacco related cancers are easily avoided (by phasing out tobacco as a marketable product) only a fraction of calculated radon deaths could be avoided by treatment of high-level houses. The exact fraction is country specific, as it depends on radon distribution parameters.
For some time NRPB have used a 2 or 3 per cent risk factor to describe lifetime exposure to radon at 200 Bq/m3. Further studies may lead to revision of this estimate, but the message has been this: if you live for all of your life exposed to 200 Bq/m3, you have about a 3% risk of dying from radon.
However, if the calculated risks for smokers and non-smokers are assessed separately, the picture changes dramatically. There is some debate over the figures, but 75% or more of so-called radon deaths may be amongst smokers.
In the United States, myths about radon risks have been promulgated since 1986 when the EPA and the CDC (Centers for Disease Control) advised action at 4 pCi/l (see Section 34), stating that homes at this (quite modest) radon level were as dangerous as smoking something less than half a pack of cigarettes per day. Later, the message was shifted to suggest "half a pack a day" and later still, in 1989, to "more than 10 cigarettes per day". Naturally, these statements from Government Agencies caused Press interest and considerable public concern.
However, the publicity was misleading, and has been severely criticised by leading scientists. As a UK body, the NRPB has not commented, but in the 1992 edition of the EPA Citizens Guide substantially revised figures are presented for the risks from lifetime exposure to radon. These suggest that non-smokers may be even less at risk than previously indicated.
For example, the lifetime risk from radon for all persons exposed to 20 pCi/l (750 Bq/m3) was originally presented by EPA as 6 to 21%. The non-smoker risk used by NRPB is 3.7%. However, in the latest EPA Guide the estimate is even lower at 0.8%. The difference between these figures (0.8% to 21%) is remarkable. For smokers however, the latest EPA Guide shows a 13.5% lifetime risk at 750 Bq/m3 - nearly 17 times the risk presented for 'never-smokers', although lower in absolute terms than previously.
Thus, at 150 or 200 Bq/m3, the risk for a lifetime non-smoker is probably closer to one cigarette per day, rather than ten, and may actually be less than the risk from one or two cigarettes per week. At such small risk factors, intervention seems hardly worthwhile if expensive and disruptive.
KEY FACTS:
The consensus of scientific opinion is that smoking and radon act synergistically. This means that the combined effect is more dangerous than being subjected to either pollutant by itself. Thus smokers are more at risk from radon than are non-smokers. This analysis was obscured for years. Sustained pressure from independent scientists forced correction of publicity material in the USA, and production of a much improved EPA Citizens Guide to Radon.