A recent research by the Radiation and Nuclear Safety Authority Finland (STUK) indicates that radon protection measures taken during the construction of new houses are effective. However, such measures have only been taken in one-half of the newly constructed detached houses. STUK recommends radon piping and sealing for all new houses.
According to STUK’s research, radon protection was deployed in 90% of new homes constructed in regions where high concentrations of radon are commonly detected. These measures have proven to be effective: the radon concentration in the protected houses is one-half lower than in older houses. Elsewhere in Finland, only 40% of new detached houses feature radon protection. In these regions, the radon concentration has reduced, at average, by 20% in comparison with older houses.
The regions with the highest radon concentrations are Eastern Uusimaa, Tavastia Proper, Pirkanmaa, Päijänne Tavastia, Kymenlaakso and South Karelia. However, exceeding the maximum amount of 200 becquerels of radon per cubic metre is not a rare phenomenon in other Finnish regions, either. Therefore, STUK recommends radon protection measures in the entire country. The regions where radon protection is used the most seldom are Lapland, Ostrobothnia, Finland Proper and Satakunta.
The average radon concentration in all of the measured houses was 95 becquerels per cubic metre; which is 30% lower than in detached houses completed in 2000–2005 and more than 40% lower than in houses completed in 1980–1999. In addition, the number of houses with a concentration higher than the maximum limit of 200 becquerels per cubic metre reduced significantly. Houses built on a vented base and solid, seamless slab featured the lowest radon concentration.
“The biggest shortcomings in radon protection were detected in ground-supported block wall structures. However, we can expect the situation to improve once construction companies gain more experience in radon protection,” says Research Professor Hannu Arvela.
STUK’s research comprised radon measurements from the indoor air of 1,500 detached houses that received a building permit in 2006. The measurements took place between March and May 2009.