Hello all
The radiological risk is not actually due to radon gas. You inhale and exhale the gas (inert noble gas) and the chances of it decaying whilst in the lung during a breath are small (and the volume of air in your lung is small).
The main risk is due to the alpha decay (of mainly Rn222) to its daughter products, principally longer lived daughters of Po and Pb (which are obviously solids).
These plate onto dust, which when inhaled can lodge in the lung. These then decay (eventually down to stable lead), giving off nice alpha (He) particles along the way (this gives the main radiation dose) and some beta/gamma radiation (the decay chain is pretty complicated).
Dare I say it?, a true killer dust.
The passive 'radon' detectors are again a bit of a misnomer. They are bits a plastic that are marked by tracks of the beta particles from daughter product in dust that has come to rest on the plastic. The tracks are then counted, assumptions made and the radiation level estimated.
<forgive any inaccuracies, this is from deep in my memory from a radiation protection MSc 22 years ago! Please feel free to correct >
Chris Dainton
Peak Environmental Solutions
(who lives & works in an area with high background lead, cadmium and radon).
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