[Strawbale] Radiating earth

[Jan Hollan]

> There is a real concern that radiation from earth in buildings are at
> harmful levels, especially in Germany and china. I would like to hear
> what you know and think of it as I am contacted by nervous clients
> about the matter. I have a hard time finding information on the
> subject. A German article was describing the high levels of radiation
> as being a big contributor to lung cancer which has freaked out the
> German population as it has a large amount of earthen houses. It is
> Thoron that is the suspect.
> If you know about how to stop radiation from walls, like paints or
> wall paper, etc, let me know also.

Sara, the only non-cosmic ionising radiation which may be relevant on 
several per cent of EU area, is that within lungs, from decay products 
of radon attached to walls of lung hollows - as that radiation is very 
short-reaching. All radon comes from the ground. Non-negligible amounts 
concern mostly just granite rock areas, when not covered by a thick layer 
of sediments. In such areas, showering with ground water may be a problem 
too -- due to inhalation of gas escaping from that water (even if water is 
perfectly suited for drinking).

The easiest measure against high interior levels of radon in those special 
granite lanscapes is to have the bottom floor some decimetres above 
ground, with air moving below it (of course, you can store anything 
there...). Air convection is orders of magnitude stronger than diffusion, 
so flux from the ground cannot affect the indoor air. Free-air 
concentrations are harmless everywhere.

Shortly, don't bother about ionising radiaton. Only if some spot would 
really have a rare radon problem, use proper building measures - for 
everybody's good, as such raised floors can be easily insulated with 
a thick layer of straw... And rainwater can be used for showering.

best regards,

  Jenik

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                              Jan Hollan, Ph.D.
CzechGlobe - Global Change Research Centre of the Acad. Sci. Czech Rep.

 			           home:
Lipová 19, 602 00 Brno                              +420 5 43 23 90 96

              volunteer of the Ecological Institute Veronica
Panská 9, 602 00 Brno, Czechia                  http://www.veronica.cz

e-mail: hollan at ped.muni.cz              http://amper.ped.muni.cz/jenik
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