“…As in [3], an equilibrium factor of 0.5 was used, as was the relationship, derived by the NRPB from epidemiological studies of the risk from radon, that one milliSievert equals 126,000 Bq m −3 h. Estimated lung cancers averted from the reduced annual radiation dose were based on the assessment that 3.5 × 10 −4 lung cancers are induced per Working Level Month [10]. Membranes were also assumed to reduce radon exposure for 40 years, an assumption adopted in earlier studies [14][15][16][17][18].…”