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

[RadiumProj@cs.com]

In a message dated 3/8/00 5:42:48 PM Eastern Standard Time, 
Harold.Reynolds@rfets.gov writes:

<< In doing hundreds of radon tests in Central Pennsylvania in the 1980s, I
 found no correlation between age/energy efficiency and radon levels.  I
 found very high levels in some old leaky structures and some very low levels
 in new very tight structures.  >>
==============

The issue is not whether some specific "old leaky structures" may be found to 
have very low levels of radon and other specific "new very tight structures" 
may have some very low levels. Measurements in PA, an area known to have very 
wide variations in radium in soil due to well documented influence of the 
Redding Prong, are likely to be quite variable home to home.

Any one general type of construction will have a wide distribution of mean 
radon levels given siting in different areas with a wide range of radium in 
soil or soil permeability, or radon in water, or any number of other factors 
on radon inputs to a given home.

The key issue is what happens when a given home is made energy efficient. 
Does the average radon level tend to go up? Numerous studies have shown this 
to be the case with rare exceptions. The point being that as the average 
housing stock is made more energy efficient, the mean indoor radon level will 
increase.

I could dig out dozens of studies on specific homes that show that energy 
efficiency measures [installing storm windows, increased insulation, vapor 
barriers, caulking, draft stoppers, etc.] taken on a single home, assessed by 
before and after measurements on that same home, lead to average increases in 
radon levels that are not insignificant. Thus, my questioning the constancy 
of radon over time for the average mix of homes over time [i.e.: it 
increasing over the past 25 or more years, on average, in the indoor 
environment] is valid. 

Has the "average" home [the mix of older homes-upgraded or not in energy 
efficiency, and new construction housing stock] seen an increase in mean 
radon level indoors due to changes in energy efficiency measures over the 
past 40 years? I believe this is quite likely, and that this is a very 
important point that cannot be dismissed or simply brushed aside by looking 
at radon measurements for different homes [even if of the same general 
construction] in different places. 

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




 
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