Cost–benefit analyses of radon mitigation projects

Radon is a radioactive gas that enters buildings and is known to cause lung cancer. Danish building regulation recommends simple remedial measures for radon levels between 200 and 400 Bq m−3, and more effective methods for levels above 400 Bq m−3. The Danish National Board of Health found that radon levels in 4.6% of the dwellings were above the reference level, and that the distribution of radon levels in Danish one-family houses is lognormal with a geometric mean of 57.7 Bq m−3 and a geometric standard deviation of 2.28. The purpose of the paper is to present a cost–benefit analysis of a possible future governmental intervention against radon in existing Danish one-family houses. In other words, it seeks to answer the question: is it socio-economically worthwhile to avert lung cancer deaths by reducing radon levels in the most exposed dwellings? The results indicate that an intervention based on the anti-radon measures recommended by the Danish building regulation would, if implemented, avert less than 30 deaths each year. By comparison, a total of 300 people die from radon exposure annually in Denmark. The total costs exceed the valuated health benefits by €62 million (6% discount rate). It is concluded that it is not socio-economically favourable to reduce radon levels in existing Danish one-family houses. These results are based on a discount rate of 6%, a value of preventing a statistical fatality of €1.4 million, and a relatively high cost of remediation in Denmark compared to other countries. Based on the sensitivity analysis, the conclusion will be different if a discount rate of 4.3% or less is used, or if the value of preventing a statistical fatality is €2.54 million or higher, or if the cost of remediation is reduced.