RE: AW: Denver, BEWARE!

["Wesley" <wesvanpelt@att.net>]

Richard and All,



Yes, it gets complicated. Let me try to explain.



The slope "B" is the relationship between lung cancer and RADON, not

altitude. When you stratify the slope "B" for radon in 10 bins, each with

very similar altitude, the slope "B" becomes less negative, on average. 



What I found really amazing when I did the research was that the graph of

lung cancer versus radon looked no more correlated than the graph of lung

cancer and altitude.  As a working hypothesis (not a final conclusion) I

would say that both increased radon and reduced oxygen concentration (higher

altitude) protect against lung cancer.



Thanks for graphing the data!



Best regards,

Wes

Wesley R. Van Pelt, PhD, CIH, CHP

Wesley R. Van Pelt Associates, Inc.

 



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

From: Richard L. Hess [mailto:lists@richardhess.com] 

Sent: Sunday, December 19, 2004 10:58 PM

To: RuthWeiner@AOL.COM; WesVanPelt@att.net; radsafe@list.vanderbilt.edu

Subject: Re: AW: Denver, BEWARE!



At 05:54 PM 12/19/2004 -0500, RuthWeiner@AOL.COM wrote:

>Richard et al:

>

>I think "correcting for oxygen" means correcting for the fact that the 

>atmospheric pressure is less at 5280 feet than at sa leve, so there is 

>less oxygen available.  This is a well known phenomenon (we are a mile 

>high here in Albuq. also).  I don't think the idea was that oxygen is a 

>carcinogen, but that metabolism, breathing rate, saturation of hemoglobin, 

>etc are affected

>

>Ruth

>



Thanks, Ruth and Franz,



I'm still confused,  because Franz reminded me of the graph I made on an 

airplane a few years ago--and at altitude (IIRC about 41,000 feet) we were 

up at about 250µR per hour (as measured on an Aware RM-70 pancake G-M 

tube)--and I understood from RADSAFE at the time, that the G-M tube 

under-reports the high-energy. For the graph, please see 

http://www.richardhess.com/rad/lax_chi.jpg



When I'm a mile high, I breathe harder than at sea level, so I naturally 

thought that the body makes up for the thinner air by trying to inhale more 

of it.



So we have Cohen's data for Radon, Wes's data for altitude, and then Franz 

throwing in the reduced shielding aspect. Even with Wes correcting for 

altitude I'm not sure I understand the effect that he's discussing. I took 

the data from Table 2 of Van Pelt's paper and did a simple graph in Excel. 

I even added a 2nd order polynomial trend line. See 

http://www.richardhess.com/rad/cohen_binned_by_van_pelt.jpg



I still don't see a correlation between the slope "B" of the overall data 

and altitude. I see changes, I don't see a correlation--but I never was 

very good at statistics. Several years ago, I worked on a project with a 

Caltech statistician and he and I kept trying to get the other to explain, 

in simple terms, what was going on. I think we both saw the light that it 

was hard to reduce our own practice to simple terms the other could 

understand--but we got through it.



Cheers,



Richard 









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