Radon is a radioactive noble gas that originates in uranium. It occurs in greater or lesser amounts in the soil, so-called ground radon, which is the most common cause of radon problems in indoor air. But radon can also come from building materials, and then blue concrete.
In Sweden, blue concrete is the building material that causes problems with radon. It was used as a building material between the years 1929 to 1975 and contains alum slate. The blue concrete can be high-beam or low-beam depending on where the slate was broken. Research reports emerged around the 1970s that showed that blue concrete emitted radon gas, and it was decided that it could no longer be produced. Until 1975, blue concrete was available, and it has been found that it was used in houses until about 1980.
Radon is neither visible nor smelly. A measurement must be made of the home to find out how much radon there is. The Swedish Radiation Safety Authority estimates that about 500 people in Sweden die of cancer of the lungs and respiratory tract caused by radon every year. The risk of being affected increases with increased exposure to radon. For this reason, The Swedish Parliament has set an intermediate target that all housing must be below a limit value of 200 Bq / m³.
For more information, please visit https://www.stralsakerhetsmyndigheten.se/en/areas/radon/