[ RadSafe ] Radon consensus question

[Otto G. Raabe]

At 02:27 PM 5/13/2010, you wrote:
>I recognize there are people on Radsafe that do not agree with the EPA
>Action Level of 4 pCi/l of radon in air, and I respect that.  I am a
>little curious about how high the levels have to be before there is
>consensus that something should be done.
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May 14, 2010

An "action level" of 8 pCi/L in homes would not be unreasonable.

A careful case control study of radon in homes shows that lung cancer 
adjusted odds ratio (relative risk) goes DOWN markedly as radon 
concentration goes UP from 25 Bq/m3 to 250 Bq/m3. Only for radon 
concentrations well above 250 Bq/m3 does the risk begin to rise (R.E. 
Thompson, D.F. Nelson, J.H. Popkin, Z. Popkin, "Case-Control Study of 
Lung Cancer Risk from Residential Radon Exposure in Worcester County, 
Massachusetts, Health Physics 94: 228-241, March 2008).

In addition, the downward slope in risk that was observed in this 
newer study seems to overlay almost perfectly the lung cancer 
mortality reduction slope shown by Bernard Cohen in his 1995 Health 
Physics paper (B.L. Cohen, "Test of the Linear-No Threshold Theory of 
Radiation Carcinogenesis for Inhaled Radon Decay Products". Health 
Physics 68. 157-174, 1995).

The authors of the newer paper explain quite well the reasons that 
caused previous case-control studies to obscure this phenomenon.

My own studies of internal emitters suggest that a lifetime lung dose 
less than 20 Sv is unlikely to result in a significant lifetime risk 
of lung cancer induction (O.G. Raabe, Concerning the Health Effects 
of Internally Deposited Radionuclides, Health Physics 98: 515-536, 
2010). Of course, there is the probable synergistic effect of 
cigarette smoking that needs to be considered at higher (but not 
lower) radon levels.

Calculating  imaginary lung cancer deaths as EPA apparently does for 
exposures below 4 pCi/L is shear nonsense!

Most homes in Colorado are well above 4 pCi/L and Colorado has one of 
the lowest lung cancer rates of all of the 50 States.

Otto

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Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
University of California
One Shields Avenue
Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
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