This report provides a good review of recent epidemiological studies on lung cancer risks from radon exposure. Especially important is the finding from the pooled analysis of epidemiological studies, where a statistically significant increase in lung cancer risk is shown for exposure below annual average concentrations of 200 Bq/m3 . The consequence of this finding should be that the reference level for radon in buildings should be 100 Bq/m3, in line with the recommendations of WHO. Radiation exposures from radon can be reduced substantially with relatively inexpensive mitigating actions. If suitable preventive measures are implemented during construction of new buildings, the costs associated will be very low. The NRPA view is that the exposures from radon should be kept as low as reasonably achievable, and the best way to ensure this is to avoid radon entry into buildings, ie to focus on the source of exposure. It is not acceptable to allow radon concentrations that are known to increase the risk of lung cancer significantly.