I have noticed that whenever the topic of radon comes up there are two probable reactions: 1. IQ quenching panic. Generally exhibited by members of the public at large. 2. Discussion quenching disgust. Most commonly displayed by devotees of the hard sciences. (Sometimes accompanied by hand-waving) I would like to posit the existence of a third state: enlightening explanation. Specifically, I am in search of a derivation of the number of years required for a cumulative exposure of x milliSieverts of radiation in the presence of y picoCuries/liter of alpha radiation from radon. My own calculations have led me to conclude that for x = 100 it would take over 6,000 years for lungs of 2kg mass and 5 liter volume to reach this level given a Q of 20 and N of 0.12 (wikipedia) in the presence of 2 pCI/liter assumedly generated purely by alpha particles with an energy of 6.4MeV (highest decay energy for Radon products I could find). Alarmingly, or perhaps annoyingly, this disagrees hugely with data from the NCRP indicating an annual effective dose in the neighborhood of 1.7mSv for 1 pCi/liter, which would get you to 100mSV in only 29 years for a 2pCi/liter situation. If anyone (preferably not within groups 1 or 2 above) can shed some light on this disagreement, I would be most appreciative.