Energy and Environment

Radon in indoor air

The concentration of radon in indoor air varies through the year and through the day. To find the mean value for the concentration in one year, long-term measurements, 2-3 months, are necessary. The concentration of radon is most stable and at its maximum during the winter, and the measurements should therefore be performed in the period from medio October to medio April. Institute for Energy Technology offers measurements of radon with alpha track detectors. This method is appreciated as the number one method for measurements of radon in indoor air.

Haugen, Ann-Helen

Senior Engineer

Ramsøy, Tore

Section Head


When contacting us, we will send you a parcel containing an alpha track detector in a radon tight plastic bag. The moment you open the bag, the measurement period begins. The detector should be exposed for two to three months. Write down the start- and stop-date on the questionnaire that follows with the alpha track detector and answer the questions about your home. In the parcel you will find envelopes for returning the detector and the questionnaire as well as detailed directions for use.

NRPAs recommended action level for radon concentration in dwellings is 100 Bq/m3, with an absolute maximum value of 200 Bq/m3. Effective remedial measures should be taken as soon as possible to reduce the radon concentration if the year mean value is greater than the action level. It is recommended that the radon measurements are repeated after remedial measures are implementet to verify that the measures are sufficient. NRPA consider the risk associated with radon exposure to be acceptable for the population if the radon concentration in all living rooms in all buildings is below the maximum level (200 Bq/m3).

It is also possible to do short-term measurements of radon in indoor air. The measurement period can then be reduced to two weeks. This method gives a good value for the radon concentration in the measurement period, but it can not be used to calculate the year mean value.

The price for one radon measurement (alpha track detector) is at present NOK 545 (+ VAT and COD).

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