Quite and agreed but it is a misnomer to suggest 222 is the ONLY isotope of
note.
Quick thought - What about outdoor air then, does that not affect anyone and
how does that figure into assessment? Radon impacts outside too....
Anyhow
Bear in mind that the decay chain does not just happen where you want it to,
it happens in ambient surroundings as well (depending on chemical source),
therefore all isotopes have a potential to impact, albeit some more than
others I appreciate that. E.g. Rn 211 L50 of c.15hrs and Rn 210 with L50
2.4hrs.
But the important point is that noble/inert does not mean non-radioactive.
Kind regards
Russell MRSC FGS
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of Chris
Dainton
Sent: 14 April 2011 16:04
To: [log in to unmask]
Subject: Re: Radon - outside....
But in terms of radiological risk in indoor air from natural rock sources -
Radon-222 is the main starting point of the decay chain to worry about.
Radon isotopes with shorter half lives would have mostly decayed before
intrusion in the building. For example, Radon 220 has a half life of 55
seconds compared with Radon-222 with a half life of 3.8 days.
Chris Dainton
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