Handbook of Radon.
29. Risks from passive smoking: possible links with radon.
The possible role of passive smoking in radon deaths is a complicated issue, and one that is likely to be the subject of further debate. However, irrespective of the exact interactions, two facts are clear enough already.
1. Passive smoking leads to an increased risk of lung cancer and is responsible for much respiratory illness in both children and adults. It is remarkable that there has not been more protest about this suffering, since it is entirely preventable.
2. There is no doubt that a room containing cigarette smoke may have a lower fraction of unattached radon daughters than might otherwise be the case. This could lead to a lower risk from the radon because unattached radon daughters have a better chance of being deposited in the lung in areas thought to be most susceptible to damage by irradiation.
However, because smoke particles have low mobility (compared with smaller aerosol particles) there is less deposition of radon daughters onto surfaces, and correspondingly more airborne radioactivity for a given radon level. On balance, it is thought that an overall reduction in dose may result.
However, breathing the cigarette smoke may give an increased risk of cancer simply because it is a powerful carcinogen. One factor here may be that tobacco itself is radioactive, and some of the activity is deposited onto lung tissue. Whether the reduction in one risk outweighs the increase in the other is a moot point.
Given the other deleterious effects of breathing cigarette smoke, it is probably best avoided. It cannot be recommended that smoking is a good way of reducing health risk by lowering the unattached fraction of radon daughters.
An interesting and related point is that simple desktop fans installed in rooms can markedly effect the concentrations of airborne radon daughters, and if combined with a harmless fine aerosol to reduce the unattached fraction still further, could lead to significant dose reduction for minimal costs. This is one possible route to dose reduction not involving disruptive building works.
Statistics quoted for passive smoking in the UK are typically 'a few hundred deaths per year'. Often 600 is quoted. This is similar to the number of radon deaths postulated to occur annually in non-smokers from lifetime exposure to 20 Bq/m3 - the UK average radon level in homes: taking 600,000 deaths annually as a base, 0.1% of these is 600.
It is interesting to speculate on commonality: how many lung cancer deaths might be owing to a combination of passive smoking and exposure to low doses of radon? Simple models class radiation as an initiator of cancer and chemicals in cigarette smoke as a promoter. If wholly true then radiation exposure of children may be more serious than for adults, and passive smoking in infants not so serious as in adults, except for respiratory and other problems having no latent period. This is probably a gross simplification, and entirely wrong!
KEY FACTS:
There are competing effects in the interaction of tobacco smoke and radon decay products. On balance, a room containing cigarette smoke may present less of a risk in radon terms than the same room without the smoke. However, the chemical dangers of cigarette smoke may outweigh these benefits. Passive smoking cannot be recommended as a technique to reduce the risks from radon.
Studies of tobacco smoke and radon illustrate the possible benefits of altering both attached fraction and deposition rates as cheap techniques to reduce radon risks in the principally used rooms of a house without resort to extensive building works.