AW: [ RadSafe ] Re: Residential radon risk

[GELSG at aol.com]

Dr. Cohen:
 
As I mentioned before, I have not seen much beyond anecdotal evidence for  
average unattached fraction values for the average home.  My observations  in my 
own home, both with and without active electrostatic air cleaning, is that  
there is always some dust.  An electrostatic precipitator certainly helps  to 
remove dust, but there are many different ways to "resupply" dust to the home  
environment, some of which I mentioned previously.
 
If it were shown that home electrostatic precipitators did not drastically  
reduce the average unattached fraction (it might not take that many dust  
particles per cubic meter to provide sites for attachment), would you then agree  
that use of such a device in the average home situation might substantially  
reduce lung doses from radon daughters?
 
Gerald Gels
 
In a message dated 6/2/2005 11:50:03 P.M. Eastern Standard Time,  
blc+ at pitt.edu writes:

Dear  Philippe:
Many thanks for this info. If the variation of unattached  fraction is so 
large, why do mines depend solely on WL? In any case, the  variation in 
homes can be very much larger because of systems for dust  removal in 
common use.







Dr. Cohen:
 
I generally agree with your work and conclusions on indoor radon.   However, 
the statement below troubles me.  In theory, in laboratory  conditions, one 
can approach a UF of 1.0.  However, (and I have seen very  little data on this 
point) I have never heard of real world UFs of more than  0.1, much less 1.0.  
If you do have such data, I would like to see  it.  In my house, we always 
seem to have plenty of dust, even with the  electrostatic precipitator running.  
I have always believed that, in the  real world of opening doors and leaking 
windows and cooking and playing  children, there will always be plenty of 
"replacement dust" particles.  In  that case, I would take exception with your 
conclusion about electrostatic  precipitators, and state that they would be a very 
good means of reducing lung  exposure to radon daughters in homes that are 
not laboratory glove boxes.   As such, we should be actively encouraging, not 
discouraging, their use.
 
Gerald Gels
 
_blc+ at pitt.edu_ (mailto:blc+ at pitt.edu)   wrote:
"As an example, one 
can drastically reduce the WL by removing the dust (for example, with an  
electrostatic precipitator), but the newly formed radon daughters have  
no dust to attach to, so UF = 1.0, and the danger is not  reduced."