Aviation officials say passengers and aircraft crews shouldn't
be overly concerned about negative health effects caused by
exposure to cosmic radiation during trans-polar flights as people
would have to make more than 200 such flights a year to absorb
enough radiation to be affected.
The comments follow the recent launch of China Eastern Airlines'
trans-polar Shanghai-New York route.
The atmosphere is thinner in polar regions than at the equator
so more radiation finds its way to earth at the poles.
Medical experts said people who fly over polar areas absorb more
cosmic radiation than normal and should take measures to protect
themselves like eating vitamins. However, they added that the
amount of radiation is within the limits of what is considered
safe.
The Shanghai-New York flight takes 14 hours reducing travel
times by six hours compared with transit flights that avoid polar
areas.
Insiders said airline companies are increasingly turning to
polar routes because of the decreased chance of turbulence and
shorter flight times.?
But frequent fliers and flight crews that work polar routes have
expressed their apprehension about being exposed to cosmic
radiation.
"People are exposed to cosmic radiation during polar flights.
The amount a pilot receives each time he crosses a polar area is
equal to more than four times what a patient receives while having
an X-ray," said Ge Shengqiu, a researcher at the Medical Research
Institute of the General Administration of Civil Aviation of China
(GACA).
Ge said a pilot absorbs about 0.093 millisieverts (mSV) of
radiation during each trans-polar flight compared with the 0.02 mSV
a person absorbs during an X-ray. However, it was almost impossible
for passengers on such flights to absorb enough radiation to cause
health problems.
Li Zhe, the division chief for flight standards at GACA, echoed
Ge's comments, noting that trans-polar flights wouldn't harm the
health of the pilots, flight attendants or passengers.
The International Commission on Radiological Protection has
capped the amount of radiation a person can absorb over the course
of a year at 20 mSV. Ge said that if someone absorbed 0.093 mSV of
radiation during each trans-polar flight they'd have to make 215
such flights in a year to reach the recommended limit.
In response to widespread concerns many international airlines
seek to avoid the effects of radiation by limiting the number of
trans-polar flights their crews make each year.
China Eastern Airline's flight attendants generally work only
one trans-polar flight every two months, said an employee of the
company.
The employee added that 500 flight attendants had obtained
American visas to work on such flights. Each flight requires 14
attendants and there are four such flights each week. These numbers
ensure that no attendants will come close to the radiation
limit.
Ge said pregnant air hostesses should be aware of cosmic
radiation. "However, usually air hostesses switch to ground
services after they become pregnant," he added. Ge also suggested
people could take precautionary measures by eating more fruit and
vegetables particularly those rich in vitamins A and C.
(China Daily December 19, 2006)