The Norwegian Radiation and Nuclear Safety Authority (DSA) recommends radon levels are kept as low as possible in every building. Radon mitigation should always be performed when the radon levels reach 100 Bq/m3 or more in a living space. DSA recommends mitigations should also be performed below 100 Bq/m3 if the mitigations are simple and reduces the radon levels significantly.
DSA recommends radon threshold levels should always be kept at maximum 200 Bq/m3. Workplaces, schools, kindergardens, commercial buildings and rental houses should be within acceptable radon levels regulated by the DSA. There are an estimated 175 000 Norwegian buildings with radon levels above 200 Bq/m3.
| National and maximum values for radon in indoor air | |
|---|---|
| 200 Bq/m³ |
The national value for radon levels in existing residences and amenities, which are used for general purposes. The Public Health Agency of Sweden’s general advice on radon indoors FoHMFS 2014:16 |
| 200 Bq/m³ |
Maximum values for radon levels in new buildings. Maximum values for radon levels in new buildings.BFS 2011:6 including amendments BFS 2011:26 (BBR 19) |
| 0.36 x 106 Bq h/m³ per calendar year |
Maximum value for how much radon a person may be exposed to in one year. The value applies to workplaces, for work other than underground work. This corresponds to a radon level of approx. 200 Bq/m³ for an annual working time of 1,800 hours, i.e. normal full-time work. Maximum value for how much radon a person may be exposed to in one year. The value applies to workplaces, for work other than underground work. This corresponds to a radon level of approx. 200 Bq/m³ for an annual working time of 1,800 hours, i.e. normal full-time work.AFS 2011:18 |
| 2.1 x 106 Bq h/m³ per calendar year |
Maximum value for how much radon a person may be exposed to in one year. The value applies to underground work such as rock and mine works or construction work underground. This corresponds to a radon level of approx. 1,300 Bq/m³ for an annual working time of 1,600 hours, (standard working time for public works underground is 36 hours per week). Maximum value for how much radon a person may be exposed to in one year. The value applies to underground work such as rock and mine works or construction work underground. This corresponds to a radon level of approx. 1,300 Bq/m³ for an annual working time of 1,600 hours, (standard working time for public works underground is 36 hours per week).AFS 2011:18 |
| 0.72 x 106 Bq h/m³ per calendar year |
Maximum value for how much radon a person may be exposed to in one year. The value applies to underground work in completed and habitable rock shelters and installations in rock. This corresponds to a radon level of approx. 400 Bq/m³ for an annual working time of 1,800 hours. Maximum value for how much radon a person may be exposed to in one year. The value applies to underground work in completed and habitable rock shelters and installations in rock. This corresponds to a radon level of approx. 400 Bq/m³ for an annual working time of 1,800 hours.AFS 2011:18 |
There is also a national value for gamma radiation (a type of radiation that can damage the body’s cells) in new buildings. Blue aerated concrete, a construction material, emits gamma radiation, but in such low quantities that it is not normally a danger to health. But if the value is higher than 0.3 microsievert per hour (0.3 µSv/h), the radon level in indoor air should also be measured.