Radiation risks low for Hawai'i fliers

By Susan Hooper
Advertiser Staff Writer

Even though Hawai'i residents are forced to fly to get anywhere, their potential exposure to in-flight radiation is relatively low, travel experts say.

That's because the longer routes Hawai'i passengers generally fly go east and west, far from the danger zones of the North and South poles.

In these jittery times, exposure to radiation may be fairly far down on most fliers' worry lists. But the phenomenon is real, experts say, because radiation from stars and solar flares can penetrate airplanes. The risk of exposure is greater at higher altitudes and on flights traveling closer to or over the North or South poles, experts say. Low-altitude flights near the equator have a lower risk.

"I think a flight from here to Asia would be actually a fairly low risk because you're much closer to the equator," said Dr. Vernon Ansdell, a general internist and director of the travel and tropical medicine clinic at Kaiser Permanente's Honolulu clinic. "And from here to the U.S. Mainland would be a relatively low to moderate risk."

Experts say there is little firm data on in-flight radiation exposure. But a Wall Street Journal report published yesterday said a Tokyo-Honolulu flight on United Airlines exposed passengers to the equivalent of 0.8 X-rays, as did a Honolulu-San Francisco flight on Hawaiian Airlines.

That means a traveler would have to make 62 one-way flights on those routes a year before reaching the federally recommended limit for radiation exposure, estimated at the equivalent of 50 X-rays a year.

Interisland flights, because they are short hops made at lower altitudes relatively close to the equator, are even more safe, according to local experts.

"The worst-case scenario would be over the poles at 40,000 feet, whereas the best-case scenario would be at low altitude at the equator," said Joe Mocarski, a Hawaiian Airlines long-haul pilot.

With respect to in-flight radiation, "Interisland flying is not nearly as hazardous as high-altitude, long-range flights," Mocarski said.

Ansdell recommends that travelers limit the number of polar routes they fly each year and avoid traveling during periods of solar flares.

He also said one medical guideline advises women to fly no more than 200 hours during pregnancy, because of the risk of exposure to radiation.

Asked where he would place in-flight radiation on a list of dangers associated with flying, Ansdell said "low to middle."

Of more concern are turbulence, which can cause serious injury or death, and deep-vein thrombosis, or blood clots in the leg, which can break off and travel to the lung, causing death, he said.

"A lot of evidence suggests (cosmic radiation) is not something we should be particularly concerned about at all, but because there are so many unknowns in the equation, that's why it's still a low to moderate concern," he said.

Nevertheless, Ansdell said, "I really don't want the message to get across, 'You thought it was dangerous to fly; now it's really dangerous to fly.' Flying is very safe and this doesn't really alter the equation, as far as I'm concerned."