Radon causes lung cancer

Radon is a colourless and odourless noble gas that is present in the soil and can penetrate the indoor air of buildings. Long-term exposure to high radon levels increases the risk of lung cancer. Radon exposure is estimated to cause 150-270 cases of lung cancer each year in Finland (1).

Radon is a radioactive substance, and its decay produces alpha radiation. Approximately two thirds of the annual radiation dose received by Finns results from radon in indoor air (3). Radon or its decay products in the air are inhaled into the lungs where most of the radiation from radon is directed. The radiation dose received into the lungs increases the risk of lung cancer. The longer the stay and the higher the radon level, the higher the risk.

In Finland, 2,800 cases of lung cancer are diagnosed each year, of which even 270 is associated with exposure to radon. Next to smoking, indoor-air radon is the most important known cause of lung cancer. Studies have shown that long-term exposure to radon levels of 100 Bq/m3 is associated with a 16% increased risk of lung cancer (2). If radon levels in all buildings could be reduced to 25 Bq/m3, 100-170 lung cancers could be prevented each year. However, it is impossible to estimate the risk of lung cancer for an individual person, as the link between radon exposure and lung cancer has been estimated by studying large population groups. The occurrence of cancer is always the sum of several factors and chance.

For smokers, the risk caused by radon is higher than for non-smokers. Living thirty years in an environment with a radon concentration of 700 Bq/m3 doubles the risk of developing lung cancer by the age of 75. The risk of lung cancer for a smoker without radon exposure is 10%, and 20% for a smoker living at 700 Bq/m3. Similarly, the risk of non-smokers without radon is 0.5% and doubles to 1% with radon. Most radon-induced lung cancers occur among smokers, men and people aged 65 and over, as these groups have the highest incidence of lung cancer. Radon can therefore be said to cause lung cancer most typically in combination with smoking.

Current understanding is that radon does not cause health problems other than lung cancer. It does not cause allergic reactions, dizziness, fatigue, or other similar sensations. However, further research is ongoing for other types of cancer.

Furthermore, radon does not harm objects or food stored in an environment with a high radon concentration. When an object is taken away from that environment, the radon decay products accumulated on its surface disappear within a few hours. 

European Code Against Cancer (WHO) advises you to check the radon levels in your home.
12 ways to reduce your cancer risk https://cancer-code-europe.iarc.fr/index.php/fi/ 


  1. Kurkela O, Nevalainen J, Pätsi SM, Kojo K, Holmgren O, Auvinen A. 2023. Lung cancer incidence attributable to residential radon exposure in Finland. Radiat Environ Biophys, 62, 35-49 https://link.springer.com/article/10.1007/s00411-022-01004-1 
  2. Darby et al. 2005. Radon in homes and risk of lung cancer: Collaborative analysis of individual data from 13 European case-control studies. British Medical Journal, 330, 23–227 https://www.bmj.com/content/330/7485/223 
  3. Suomalaisten keskimääräinen efektiivinen annos vuonna 2018 (Average effective dose for Finns in 2018. In Finnish only, julkari.fi) 
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