[ RadSafe ] Hot particles on automobile air filters

Fri Jun 24 19:27:53 CDT 2011

Jerry, 

I agree that there might be some Pb-210/Po-210, but because of the longer half lives, the specific activity is much lower, and so might be below detection limits.  Also, these are primarily alpha emitters (some beta from progeny) with relatively few photon emissions.  Still these could be another confounder. 

Cindy Bloom 

----- Original Message -----

From: gelsg at aol.com 
To: radsafe at health.phys.iit.edu 
Sent: Friday, June 24, 2011 7:01:50 PM 
Subject: Re: [ RadSafe ] Hot particles on automobile air filters 

Just FYI, if that filter had been in place for several months (mine has not been changed for several years), all those radon short-lived daughters that were attached to the dust on the filter would have decayed to the Pb-210/Po-210 longer-lived daughters.  I am not sure exactly what was detected, but radon daughters should not be discarded as a possibility based only on being removed for a few weeks. 

Jerry Gels 
Cincinnati, OH 

-----Original Message----- 
From: radbloom at comcast.net 
To: The International Radiation Protection (Health Physics) Mailing List <radsafe at health.phys.iit.edu> 
Cc: The International Radiation Protection (Health Physics) Mailing List <radsafe at agni.phys.iit.edu> 
Sent: Fri, Jun 24, 2011 11:14 am 
Subject: Re: [ RadSafe ] Hot particles on automobile air filters 

I'm curious about the retention efficiency of iodine vs cesium on these 
ilters.  I know the chemical form of the iodine would affect its 
ollection efficiency, but typically carbon filters, not particulate filters, 
re used to (most efficiently) collect iodine species.  Also, it's noted that 
he filters have been in transit for a long time - is that long compared 
o I-131's 8-day half-life, or just long compared to the radon progenies' 
alf-lives? 

Cindy Bloom   

---- Original Message ----- 

rom: "Chris Busby" <C.Busby at ulster.ac.uk> 
o: "The International Radiation Protection (Health Physics) Mailing List" 
radsafe at agni.phys.iit.edu>, "The International Radiation Protection (Health 
hysics) Mailing List" <radsafe at agni.phys.iit.edu>, "The International Radiation 
rotection (Health Physics) MailingList" <radsafe at agni.phys.iit.edu> 
ent: Friday, June 24, 2011 9:08:16 AM 
ubject: Re: [ RadSafe ] Hot particles on automobile air filters 

----Original Message----- 
rom: radsafe-bounces at agni.phys.iit.edu on behalf of kmcheng1 at netvigator.com 
ent: Thu 23/06/2011 22:29 
o: The International Radiation Protection (Health Physics) Mailing        List; 
he International Radiation Protection (Health Physics)        MailingList 
ubject: Re: [ RadSafe ] Hot particles on automobile air filters 

 simple demonstration we used to show to junior school students about natural 
adioactivity was to cover the nozzle of a vacuum cleaner with a filter paper, 
urn on the cleaner for 5 to 10 minutes and then put the filter paper in front 
f a GM counter.  There were normally sufficient radon progeny on the filter 
aper to give a significant count rate above the background.  The same would be 
xpected on an automobile air filter shortly after it is taken out of a running 
ngine. 
That is probably nothing new, unless the gamma spectrum shows that there are 
omething else other than radon progeny. 
Clement Cheng 
adiation Health Unit 
epartment of Health 
ong Kong SAR, China 

 ???: "Brennan, Mike  (DOH)" <Mike.Brennan at DOH.WA.GOV> 
 ??: 2011/06/24 ??? ?? 03:29:24 HKT 
 ???: "The International Radiation Protection (Health Physics) MailingList" 
         <radsafe at agni.phys.iit.edu> 
 ??: Re: [ RadSafe ] Hot particles on automobile air filters 

 Ah, so the data is robust enough to share with friends, so they can 
 spread the news worldwide, but not robust enough to expose to 
 potentially critical examination.   

 How very, very, usual. 

 >Sorry, Its not my data and you will have to wait for it to be 
 published. It was meaursed in the USA by a colleague. I do however have 
 my own data and will share it with you in due course. 
 Sincerely 
 Chris 

 Sinecerly 
 Chris 
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But these filters have been across the Pacific and in the mail system for a long 
ime. The gamma spectrum of the filters shows Cs137 and I131. What you say is 
hat the particles in the filters are hot (register as splashes on Xray film) 
ecasue of radon daughters? yes? 
hris 
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