WHO | Radon and cancer

• Radon is the second most important cause of lung cancer in many countries.
• Radon is estimated to cause between 3% and 14% of all lung cancers, depending on the average radon level in a country.
• Radon is much more likely to cause lung cancer in people who smoke, and is the primary cause of lung cancer among non-smokers.

...Significant health effects have been seen in uranium miners who are exposed to high levels of radon. However, studies in Europe, North America and China have confirmed that lower concentrations of radon - such as those found in homes - also confer health risks and contribute substantially to the occurrence of lung cancers worldwide [1, 2, 3].

The risk of lung cancer increases by 16% per 100 Bq/m3 increase in radon concentration. The dose-response relation is linear - i.e. the risk of lung cancer increases proportionally with increasing radon exposure. Radon is much more likely to cause lung cancer in people who smoke.

I was made aware of the radon danger as a freshman physics student. Our professor told about an especially bad cluster west of Budapest: a coal mining town, where (1) natural radon emissions from the ground are high due to minerals with high radionuclide concentration, (2) homes were built in the sixties without proper ventilation, (3) buring locally mined (high radionuclide concentration) coal produces slag with even higher radioactivity (the fire leaves behind and thus concentrates heavy metals) which legally up to 1960 and illegally until much later was used as building material, (4) the building material produces more radon gas as breakdown product (radon-222 is the alpha decay product of radium-226).

_{*Lunatic*, n.
One whose delusions are out of fashion.}