What danger does radon gas pose?

Answer 1

Radon gas is radioactive, and as a gas, it is much more dangerous than a liquid or solid because it is airborne and can be inspired. If you breathe in radon and it undergoes radioactive decay inside your lungs, there will be some heavy biological damage. Additionally, the decay products in the decay chain from radon are all radioactive solids, and they have a low probability of being exhaled. You will effectively be stuck with a tiny radioactive source inside you. Radon decays through several steps to get to a stable isotope of lead, and all the decay events are high energy events as far as soft tissue, point blank biological damage. They're alpha and beta decay events. Radon is suspected as a leading cause of lung cancer. Radiation does that to tissue.

Answer 2

Radon's most stable, and only naturally occurring, isotope, 222Rn, has a half-life of just 3.8 days, and so is regarded as highly radioactive.

When 222Rn decays, it emits an alpha particle, which is highly dangerous when emitted from within the body (the skin is sufficient to prevent alpha particles from entering the body from outside) - and because radon is a gas, it emits alpha particles directly into the cells of the lungs, and lung cancer is the most probable adverse health effect of radon exposure.

There is no doubt that radon is carcinogenic - the International Agency for Research on Cancer, for example, has listed it as being carcinogenic to humans. The most affected victims have been miners within uranium mines, where radon is formed as a part of the uranium decay series and accumulates to very high levels in unventilated mines.

Despite its well-defined carcinogenic properties, the risks should be kept in proportion. Because of its high radioactivity, and therefore short life, only small quantities of radon are normally encountered, and the residence time for any radon that enters the body is relatively short (90% of ingested radon is lost from the body within 100 minutes), so with short exposures the typical risk is real but limited - roughly equivalent to smoking a cigarette per day.

In extreme cases, though, such as that of Stanley Watras of Pennsylvania, exposures can reach huge levels; equivalent to the cancer risk from smoking over 100 packs of cigarettes per day. Again, this should be kept in proportion - with greater awareness of the risks in radon-prone areas, and the use of modern ventilation methods, such levels of radon should never be encountered in basements and houses.