Solar storms boost radiation risk for air travelers

Passengers may be suspicious of the low-level radiation doses coming from full-body scanners being deployed at U.S. airports, but a far greater threat comes from the radiation that creeps into airliners while in flight.

The phenomenon has been well known in scientific circles for years but has never gained much mainstream attention. That may change as the Earth enters an uptick of solar storms that are expected to peak within five years.

NASA has said the amount of additional radiation during such storms can be "profound." The atmosphere protects the planet at ground level from most solar radiation, but in the air, especially on polar routes such as from the United States to northern Europe or Asia, jets fly above that protective layer.

"If you're talking about flying once or twice a year, it's not much cause for concern; once or twice a month for business is another thing," said Brent Blue, a senior aviation medical examiner for the Federal Aviation Administration and owner of Aeromedix, an aviation safety and medical company.

Last year NASA scientists finished a first round of calculating the levels of radiation exposure in flight, concluding that on a single flight from Chicago to Beijing, crew and passengers are exposed to about 12 percent of the recommended annual radiation limit.

"These exposures were greater than on typical flights at lower latitudes and confirmed the concerns about commercial flights at high latitudes," NASA said in a statement.

It is widely believed that fetuses are at greatest risk, prompting the Association of Flight Attendants, an industry union, to warn flight attendants that they might want to be reassigned to a ground job while pregnant or trying to conceive.