Re: How to become irradiated at 30 000 feet.

From:         rdd@netcom.com (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         06 May 94 18:02:15 
References:   1
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In article <airliners.1994.1160@ohare.Chicago.COM> pypbf@csv.warwick.ac.uk (D.M.Procida) writes:
>
>My friend- who, I might add, is afu-conscious- tells me that he heard (or
>read or saw) something quite worrying about air travel: on a trans-Atlantic
>flight, one receives substantial doses of radiation. This is because there
>is much less atmosphere above to absorb the nasties. I presume the radiation
>in question is gamma radiation, by the way.
>
>Anyway, he added that this dose is so strong that a single trans-Atlantic
>flight is as good as living next door to a nuclear power station for the
>rest of your life, and that you shouldn't have any x-rays for the next year.

The June/July 1990 AIRLINE PILOT (the ALPA propaganda actually had a 
technical article on this subject.  Some excerpts.

"'...the estimated liftime cancer risks due to cosmic radiation exposure
for cabin crew members flying 960 hours per year range from 90 to 1026
premature deaths per 100,000 individuals flying for 20 years on domestic
flights, and from 220 to 512 premature deaths per 100,000 individuals flying 
for 10 years on international flights.'  By comparison, about 22,000 out
of 100,000, or one in five, persons will die from cancer from all causes.

"The report also notes that the 'lifetime cancer risks for passengers
flying 480 hours per year range from 45 to 513 premature deaths for flying 20
years and from 110 to 256 deaths for flying 10 years on international flights.
In addition, there is a particular risk to the unborn--fetal exposure during
weeks 2-15 of gestation greatly elevates the risk of retardation.'
DOT cautions, however, that these risk data are not based on any study of 
actual cancer cases but on mathematical projections of the effects of low-
level cosmic radiation based on what is known about higher radiation doses."

More trivia:

A flight from Houston to Austin, with a block time of 0.6 hours, yields a
dose of 0.01 millirems.    

A flight from New York to Chicago, with a block time of 2.3 hours, yields
1.20 millirems.

A flight from Tokyo to New York yields 12.6 hours and 9.10 millirems.

A flight from New York to to Seattle yields 5.3 hours and 3.6 millirems.

A flight from London to New York lasts 7.3 hours and 4.9 millirems.

"The average person receives from 240 to 315 millirems of radiation per
year from all sources.  A chest X-ray produces about 10 millirems.  The 
recommended limit for people in nonnuclear fields is 500 mrems per year.  As 
recently as 30 years ago, 5000 millirems was the maximum allowable for
annual occupational exposure."

RE the Concorde: 

They are equipped with radiation monitors, but "are primarily solar-flare 
warning devices."  

"The monitors showed that the highest average dose-equivalent rate on a 
single flight was between 6 and 7 mrems/hour.  The average level was 4
mrems/hour.  The average encountered on the North Atlantic route between
Paris and the United States was 1.52 mrems/hour."

The article goes on to note earlier studies which guessed showed much lower 
levels of radiation (about 60%), and points out we really don't know that much
about what's going on in the real world, because we don't monitor it.  And
not knowing what goes on, we can't justify monitoring it.  A nice, typical,
FAA catch-22.

The article notes that the greatest risk is on long, high-latitude flights.


And from my old physics textbook (O'Hanian, _Physics_), I get some
random figures on typical exposures.
    Cosmic rays: 50 millirems/year
    Radioactivity of ground and buildings: 50 mrems/year
    Natural 40K in human body: 20 millirems/year
    Other natural radioactivity in human body: 4 millirems/year
    Radioactivity of air: 40 millirems/year

For various medical X-rays:
    Mammography: 250-300 millirems (!)
    Upper GI: 150-400 millirems.
    Skull: 20-50 millirems.
    Chest: 5-35 millirems.
    Dental: 10-30 millirems.


In other words, I'm really not going to lose any sleep over any of this.
It merely confirms my distrust of hospitals and dentists. :-)
    


--              
Robert "Wearing dark shades" Dorsett                                            rdd@netcom.com