Home radon levels and seasonal correction factors for the Isle of Man

Ionizing radiation dose levels due to home radon can rise to levels that wo uld be illegal for workers in the nuclear industry. It is well known that r adon levels within homes and from home to home, and also from month to mont h, vary considerably. To define an Isle of Man radon seasonal correction fa ctor, readings were taken in eight homes over a 12 month period. An average island indoor exposure of 48 Bq m(-3) (range 4-518 Bq m(-3)) was determine d from 285 homes selected from a cohort of 1300 families participating in t he European Longitudinal Study of Pregnancy and Childhood (ELSPAC) in the I sle of Man. This compares with a UK home average of 20 Bq m(-3) and a Europ ean Union average (excluding UK) of 68 Bq m(-3). Ten homes of those measure d were found to have radon levels above the National Radiological Protectio n Board 200 Bq m(-3) action level. There are 29 377 homes on the Isle of Ma n, suggesting that there could be some 900 or more homes above the action l evel. No statistical difference was found between the NRPB and Isle of Man seasonal correction factors.