Radon

Radon is an odorless, tasteless and invisible radioactive noble gas that a human cannot sense in any way. Radon can be detected only with special measuring equipment. High radon levels may cause lung cancer.

Recommendations for maximum levels of radon

• According to the decree of the Ministry of Social Affairs and Health on ionizing radiation, the reference value for indoor air radon concentration in residences and other occupied spaces is 300 becquerels per cubic meter (Bq/m3) of air.
• The reference value for indoor air radon concentration that applies to the planning and execution of a new building is 200 Bq/m3.

A gravel ridge and rock are places where radon levels may rise above the reference values. Turku has mainly been founded on clay and thus does not belong to the risk area. On the other hand, radon levels may differ significantly between buildings close to one another if one of the buildings is on rock and another one is on a field of clay.

Radon measurements

With radon measurements in residences, the aim is to investigate the average radon exposure that inhabitants are subjected to. Radon measurements in homes are conducted between the beginning of September (1.9) and the end of May (31.5), typically using an alpha track detector. The measurement should continue for a minimum of two months, but a more precise annual average is obtained when the measurement is carried out for three months or longer.

In an ordinary dwelling, two detectors are used, one of which is placed in the living room and the other in the bedroom. These rooms are typically the most frequently occupied, so the results obtained best reflect the exposure of the occupants.