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

[RadiumProj@cs.com]

In a message dated 3/9/00 12:30:37 PM Eastern Standard Time, blc+@pitt.edu 
writes:

<<  On the other hand, average radon levels did vary
 with the draftiness of the house: for houses judged to be more drafty than
 average -0.85, about average - 1.00, less drafty than average - 1.33.
    Actually the main conservation method used was to add insulation
 in walls, and that would not affect radon levels. >>
===============
Dear Radsafers:

The data cited above by Dr. Cohen on average radon levels vs. judged 
"draftiness"  shows the ratio of "less drafty than average"/"more drafty than 
average" = [1.33/0.85]= 1.56, a 56% increase in radon levels, not looking at 
individual houses before and after weatherization.  This would seem to  lend 
support my point that radon levels may have increased significantly over time 
as the overall housing stock has become more energy efficient, on average.

Further, Dr. Cohen states above that: << "Actually the main conservation 
method used was to add insulation  in walls, and that would not affect radon 
levels".>>

I don't believe the above conclusion is accurate that wall insulation would 
not affect radon levels.  Insulating walls in older homes will reduce the 
chimney effect where heat rises up walls drawing basement air [with generally 
higher radon levels] into the home.  This is especially true for older 
balloon style framing techniques where there was significant air movement up 
the wall cavities.  

Also, by reducing overall energy use, with wall insulation,  those heating 
systems that depend on outside sources of combustion air to support basement 
furnace fuel burning, will draw less outside air into the home.  I would 
think it is possible that this reduced combustion air demand might lead to 
increased  radon levels for most homes, on average, although I am not at all 
certain of this point. 

Similarly, insulating the floor of a home from a cooler basement as was often 
done, would decrease radon from the basement rising into the home through 
cracks and penetrations between the basement floor and the first level of the 
home. 

Accordingly, both wall and floor insulating measures are likely to lead to 
increased radon levels in a given home after insulation related conservation 
measures are taken.

Stewart Farber
Public Health Sciences
email: radiumproj@cs.com
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