777 Polar flights and Radiation dose
 

Many long hauls like US-India etc have polar routes. This is bound to expose passengers to higher levels of radiation. Crew and FFs will be severely affected. Is there any authentic data about safe radiation limits? What does one flight cost in terms of safe annual dose?

Oh never mind the polar flights - you're already exposed to more radiation when you're in the same room for 5 mins when the microwave oven is on.

For each transatlantic flight alone, (per sector), your body goes through the same amount of stress as though you're smoked 14 packs of cigarette. I'm talking about stress.

First of all, microwave ovens don't produce ionizing radiation. I presume the original poster was asking about ionizing radiation, like X rays, which can break chemical bonds.

Second of all, I don't know what to make of statements like "same stress as 14 packs of cigarettes." Cigarettes deliver nicotine, tars, and particulates (some with trace radioactivity) to your lungs, which then stay there for extended periods. How can you compare that with a few hours at high cabin altitude and low humidity, and very slightly increased radiation? And why not 13 packs, or 15 packs?

But for the original poster, there was a very informative and accurate article on this some years ago in the New York Times. I made a PDF of it:

http://xray1.physics.sunysb.edu/~jac..._12jun2001.pdf

For perspective, there are various ways people differ in the radiation dose they receive: by living at high altitude, by living in regions with lots of granite, by living in regions with more radon gas from the natural soil seeping into their house... But flight crews flying repeated near-polar flights (like New York to Tokyo) can easily get a dose double or triple the background dose received by people on the ground.

Assuming the figures listed in that article are correct, a person would receive 0.9 mrem/hr while on the worst case flight path. Let's call it 1 mrem/hr, which is not really anything to fret over. Again, assuming 1000 airborne hours at the area of maximum exposure, that would equal an annual exposure of 1000 mrem, or 1 Rem. For perspective, at the nuclear power plant I work at (I am a radiation protection specialist) we have an annual administrative limit of 1000 mrem per worker, which can be increased if needed. The NRC limit for annual TEDE dose is 5 Rem. So a flight crew who did nothing but fly the highest dose rate flights would receive 20% of the annual federal limit in the U.S.

can we get homer simpson in on this I am sure he can verify the safety levels

Dj, i work in the control room of a power plant (maybe yours, maybe not) and I have never gotten near one REM in one year including 60 day plus refueling outages, resin sluices etc.

That flying is a high rad gig!

For the rest of you, I work with RP techs quite often. I would say Dj is as close to a resident expert as you are going to find.

There's just a bit of a difference - you know about radiation dose, and small increases in statistical risk of leukemia (assuming a linear no-threshold model which is admittedly the most conservative model because it does not really differentiate between repairable single-strand DNA lesions and non-repairable double-strand lesions). Therefore you can make an informed judgement as part of your voluntary choice of work. I'm not sure that all flight crew A) have any idea of what their radiation dose is, and B) have the knowledge to put it in proper perspective.

Still, I agree that the added statistical risk due to these small doses is very very small - much smaller than the risks of traffic accidents to/from the airport, and enormously smaller than the risks due to smoking, or being overweight.

Thank you, altaskier for that pdf. Great article to put things in perspective. Maybe some anti-oxidents like vitamin E, C, beta-carotine wouldn't hurt..

And that amount is even higher if you are flying on US TA!

Thank you Alta skier
 

I just completed full treatment for cancer with abdominal radiation. I am an avid international flier. I just wonder now that I have had my lifetime doseage of radiation how much this old middle aged body will take. I also spent time one year living at 8,472 ft (in Alta! skiing) in my younger years. So how does that figure in? I don't know but I will still be flying half way around the world in 6 months. I guess I will take my chances. Great subject.

djbeers give a solid fact-based analysis.

There are persons that do have to understand the risk about this. For example, CO have some Chinese FAs that basically fly nothing but EWR-HKG/PEK, which use the Polar 2 route for EWR->HKG/PEK all the time, within 75 miles of N. Pole; and often Polar 4 for HKG/PEK->EWR, which is also well inside the Arctic Circle.

Unlike the pilots who fly much fewer hours and on various routes, or American FAs that rotate through the system, these FAs will have higher exposure to radiation. I see many of them females of child-bearing age too, so that's an additional concern.

The flight crews should be informed about the radiation dose accrual, and I'd say there is nothing inappropriate about assigning dosimetry to them and tracking their exposures - if for no more than litigation minimization (as we call it in Rad Protection). :)

Glad you're on the mend!!!

The localized, cumulative dose delivered to a tumor in radiation therapy is in the range of 20 to 80 Gray, according to Wikipedia. The dose you get on a polar airplane flight is more like 0.008 Gray according to that NY Times article, or in round numbers 2,000 to 10,000 times less. (For X rays the relative biological effectiveness is 1, so a Gray is about equal to a Sievert).

Conclusion? Don't worry about the flight...

don't forget fast food... (and stop using rems... its called Sieverts, heheh today's flamer post)

Rads/REMs were the units I used to use, before switching to the SI standard of Gray/Sievert. For those who really wanted to know, 100 Rad=1 Gray, 100 REM=1 Sievert, and Sievert=Gray*RBE (and also REM=Rad*RBE) where RBE is the relative biological effectiveness (about 1 for X rays).