LONG-LIVED RADON DECAY PRODUCTS AS A LONG-TERM RADON EXPOSURE INDICATOR

The different members of the uranium decay series have distinct roles to play in the scenario of indoor radon. The Rn-222 gas is the airborne carrier of the dose giving short-lived decay products. These transform into long-lived daughters (LRnD) of low activity, useful as retrospective radon tracers. Porous objects constitute Volume traps for LRnD via radon diffusion, while surfaces trap LRnD through alpha recoil implantation. Only when the build-up of LRnD activity proceeds undisturbed over many years, do we have a system which is potentially useful for retrospective radon/radon daughter exposure studies. The feasibility of using LRnD in humans and in volume and surface traps as radon retrospective monitors is discussed. It is concluded that only surface implantation sinks ace potentially well suited for long-term studies at radon levels met in dwellings.