Re: LNT models -Constancy of Radon levels over time??

[RadiumProj@cs.com]

In a message dated 3/8/00 4:25:54 AM Eastern Standard Time, 
Christoph_Hofmeyr/CNS1@cns.co.za writes:

<< When comparing the two supposed main causes, tobacco consumption is
 probably much more variable in time, and one should probably look at
 consumption for the past 3 or 4 decades in relation to consequences.  Radon
 can be assumed to be a constant factor, as it is related to uranium in the
 ground, i.e. the local geology.  >>
==============
In his self-described musings on the subject of radon and the LNT issue,  
Christopher Hofmeyr states above that " Radon  can be assumed to be a 
constant factor, as it is related to uranium in the  ground, i.e. the local 
geology." 

This is likely to be a poor assumption over the lifetime of a large fraction 
of today's residents for the following reason. Over the past many decades 
there has been an effort to reduce energy consumption in existing homes by a 
combination of measures [insulation, storm windows, weatherstripping, 
caulking] all of which will reduce air infiltration and increase indoor radon 
levels, on average. Accordingly, the radon levels measured today in the 
"average home" may not reflect the time-averaged radon levels to occupants of 
an older home which might determine a long-term residents' actual 
radon/lung-cancer dose-response relationship. Also many people who grew up in 
older, draftier homes with  likely lower radon levels will have moved into 
homes of newer construction with much higher radon levels due to their being 
built much tighter.

To the extent that radon levels in the indoor environment are likely to have 
increased with time, both due to the upgrading of older homes and in the fact 
that newer construction is much, much less subject to air infiltration [and 
dilution of indoor radon], resulting in higher radon levels, radon levels 
over time are very unlikely to have been constant with time even thought 
radium levels in local soil are constant. 

If the historical long-term  time-averaged radon levels to residents were 
much  lower to people than assumed based on recent measurements in today's 
homes, this would seem to be a flaw or serious confounding variable not 
addressed to my knowledge, in Dr. Cohen's argument regarding the lack of 
correlation between elevated radon levels and lung cancer rates.

Stewart Farber, MS Public Health [Air Pollution Control]
Public Health Sciences
email: radiumproj@cs.com
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