Re: variations in background

[BERNARD L COHEN <blc+@pitt.edu>]

On Sat, 7 Sep 2002, Michael G. Stabin wrote:



>

> I quite often cite levels of natural background radiation, for comparisons

> to other exposures. Sometimes, we say that very low exposures are "within

> the variability" of natural background. Can anyone tell me, for the US, what

> a reasonable value is for this variability? For Tennessee, we cite an

> average value of 3 mSv/y, but what would a reasonable estimate be for the

> variability of this number, for ex, one standard deviation? Thanks.



	--This breaks down into two rather separate components, radon and

gamma rays. There is a great deal of info about the radon component, and

less about gammas. It would be difficult to give a standard deviation of

their sum. For radon, it would be most meaningful to give a geometric

standard deviation, something like 2.3.