How radon affects health

Radon can cause lung cancer in humans. The radioactive gas occurs in varying concentrations everywhere in our environment. If it accumulates in confined spaces (e.g. homes), high radon concentrations that are hazardous to health can occur.

How does radon in the body affect health?

When radon decays radioactively, radioactive isotopes of polonium, bismuth, and lead are formed as short-lived decay products. In the air, they are mainly attached to aerosols.

Radon in the human body

Radon and its decay products are inhaled along with air. Gaseous radon is almost completely exhaled. However, the radioactive decay products polonium, bismuth, and lead adhere to the sensitive lung tissue and continue to decay there.

Alpha particles emitted by deposited short-lived decay products can damage the cells in the lungs – in particular the genetic material (DNA) contained in them. This may cause lung cancer.

Other human organs, especially the throat-nose-pharynx area or the skin, may also receive appreciable doses. For all other organs, the radiation dose is very small, even with increased radon concentrations. This also applies to pregnant women for their unborn babies. There is currently no evidence that long-term elevated radon concentrations indoors can cause diseases other than lung cancer.

How dangerous is radon for our health?

Inhaling radon and its radioactive decay products over a longer time increases the risk of developing lung cancer.

The International Agency for Research on Cancer (IARC) in Lyon, established by the World Health Organization (WHO), classifies radon as a human carcinogen. The Federal Office for Radiation Protection (BfS) and the German Radiation Protection Commission (SSK) agree with this evaluation.

The higher the radon concentration in the air we breathe and the longer the time we inhale it the larger is the risk of lung cancer. According to studies, it increases linearly in long-term radon concentration in the home.

The BfS has determined that around 6 % percent of all deaths from lung cancer in Germany can be attributed to reseidential radon. Between 2018 and 2022 (the period examined in the study), this was approximately 2,800 deaths per year. Radon is therefore one of the most important causes of lung cancer after smoking.

There is no indication of a threshold below which radon is definitely not a health risk. For every 100 becquerel per cubic meter of long-term radon concentration in the room air, the risk of lung cancer increases by around 16%.

Are children particularly at risk?

There is no scientific evidence that radon increases the cancer risk for children more than for adults. However, the data situation is not yet sufficient to make reliable statements.

In a European research project on radon risk, which is coordinated by the BfS, the risk for children is therefore also being specifically investigated.

For the health risk of children, the radon concentration in the home is generally likely to play the greatest role compared to other places of residence, such as school, since children usually spend the most time at home.

What influence does smoking have on the health risk of radon?

Smoking and radon reinforce each other's harmful effects on human health. Radon thus increases particularly the risk of lung cancer for those who smoke or who have smoked.

However, radon has also been shown to increase the risk of lung cancer for people who have never smoked.

How can I protect myself from radon?

The lower the radon concentration a person is exposed to in a home, the lower the lung cancer risk from radon. Simple protective measures are often sufficient to significantly reduce the concentration of radon in a building and thus the lung cancer risk.