An approach for a precise retrospective assessment of the indoor radon expo
sure using commercial compact discs (CDs) is proposed. It is based on the r
emarkable radon absorption and a track-etch properties of polycarbonate - t
he basic material of the CDs. The experimental results indicate that the us
eful range of this approach is able to cover practically the entire range o
f indoor Rn-222 concentrations. (C) 2001 Elsevier Science B.V. All rights r
eserved.