[ RadSafe ] FW: Reporter's question about lowerlimitsofdetection

[franz.schoenhofer at chello.at]

Tom, 

Regarding your comment that car air filters might be an excellent qualitative approach as to the nature of contamination you are of course right. BUT!!!! From the radiation protection  view I have to severely oppose your approach (and that of this wannabe scientist Mr. Chris) that they might be used for any radiation protection purpose. 

What is needed in the case of a nuclear accident is not a qualitative estimation (with several thousand % of error) but quantitative numbers of I-131, I-132, Cs-134, Cs-137 etc. concentrations in aerosols, in precipitation, even  more important in food and soil. 

All countries I know, including Japan, have ample sampling devices for doing it and they do not depend on a British anti-nuclear agitator to measure with outdated NaI(Tl) detectors radionuclides "over the thumb". 

Everywhere in Europe and most countries I know overseas, modern sampling equipment and analytical instruments are used. Why bother about the above mentioned British anti-nuclear agitator and his funny idea to use car-filters ??????

If you think that I am wrong, please contact me, I would appreciate it.

Best regards,

Franz

---- Tom Simpson <bullet308 at att.net> schrieb:
> It occurs to me that the analysis of car air filters is an excellent 
> qualitative approach, in that it can tell us radioactive materials were 
> present in the air at some point during the service life of the filter. 
> Of further utility would be dismantling the filters and analyzing the 
> contents both spectroscopically and physically.  Its good science within 
> its limits.
> 
> Extracting quantitative data from the same source strikes me as a lot 
> more problematic, as there are so many variables to consider. Just the 
> differencing driving habits, engine capacities and relative efficiencies 
> of the air intake systems are just a few (a fair bit of stuff settles 
> out in portions of the intake system before it reaches the filter, and 
> one might think that denser materials such as radionuclides would be 
> more prone to this).
> 
> Really, I would think to get a qualitative measure out of this, you 
> would need a lot of data from the engines EFI as to throttle position, 
> etc. for the entire time the engine was on and a bunch of data from the 
> cars manufacturer on what that means in terms of air flow through the 
> filter. And none of this is a proper substitute for particulate samples 
> taken using an apparatus that is properly calibrated as to air flow, 
> filter media of a known and fixed type that is changed and analysed at 
> regular intervals, etc etc.
> 
> -Tom