Radon causes most of the radiation received by Finns
STUK has published information about the average radiation doses received by Finns from different radiation sources that have been calculated on the basis of the information from 2018. By far the largest amount of ionizing radiation that Finns are exposed to comes from radon, and the home is the place where people are most exposed to radiation.
The average effective radiation dose received by Finns is 5.9 millisieverts (mSv). Two-thirds of the radiation dose, 4 mSv, comes from indoor air radon. About 1.1 mSv is caused by other types of natural background radiation than radiation from indoor air radon. Background radiation is partly cosmic radiation from space and partly the radiation from radioactive materials in soil and building materials. On average, the medical use of radiation causes a Finnish person an annual effective dose of 0.76 mSv. The radiation dose caused by radioactive materials in Finnish nature following nuclear accidents and nuclear weapon experiments that were carried out in the 1960s is very small.
The effective dose describing exposure to ionizing radiation is a calculated quantity that describes the detriment caused by radiation on a person’s health. As the effective dose grows, so does the risk of contracting cancer caused by radiation.
The last time STUK published calculations about the average radiation doses received by Finns was in 2012. The new numbers are different from the previous ones. For example, the use of radiation in medical examinations has grown a little, mostly due to the increase in the number of performed CT scans. Some of the changes in the numbers is caused by the new way of calculating effective doses.
New way of calculating radiation dose caused by radon
The biggest change compared to the 2012 calculations has to do with the effective dose caused by radon. The method used in the new calculations is the International Commission on Radiological Protection’s (ICRP) calculation method, published in 2017. Due to the new method, the effective dose caused by radon is more than twice of that compared to the last estimation.
Even though the risk of contracting cancer grows with the effective radiation dose, the average amounts of effective doses from different sources do not directly describe the risk. According to Teemu Siiskonen, the Deputy Director of STUK, the health risk caused by radon is estimated on the basis of epidemiologic examinations, not the effective dose. This means that the number of cases of lung cancer caused by radon does not change despite the new calculation method. Every year, an average of 280 Finns die from lung cancer caused by radon. Of these cases, 240 deaths are induced by smoking in addition to radon.
Deputy Director Teemu Siiskonen, tel. +358 (0)9 759 88 318
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