Re: Re[2]: Radon Question from Occ-Med-Env -Reply

[Ccja@aol.com]

I haven't followed this thread closely, but I think that what he means is
that it would only take about three minutes for the first alpha-emitting
daughter (Po-218) to be at 50% equilibrium with the radon inside the mask,
assuming that none of it is returned outside the mask (clearly not the case).
Is it taken for granted that we're talking only about "radon" as Rn-222, with
a 4 day 1/2life, here? What about thoron, Rn220, with a 55 second 1/2life?