Cosmic Radiation

On Thursday 25 September 2003 16:52, Al Globus wrote:
(...)
> However, others have pointed out a couple of things: The atmosphere
> seems to block most cosmic radiation (99% is best number I've seen, but
> the jury is still out). Also, the Earth itself emits quite a bit of
> radiation. On this front, how much comes from the last few meters of
> the Earth? I would expect radiation coming from lower down would be
> blocked, but perhaps I've got this wrong.
(...)

>From that link posted by Arthur
(http://hps.org/publicinformation/radfactsheets/radfact25.html), it seems
that most of the Earth-created radiation comes not exactly from the soil (as
I originally thought). That's just 8% of the total radiation at Earth
surface. And yes, I guess that is the radiation coming from the top layer of
the soil. However, the biggest fraction (55%) comes from the radon in the air
around us... It is continuously emanated by the soil and, since it is a heavy
gas, it may stay really close to the surface - where we live...