In-flight radiation originates from the sun and "deep space." It penetrates the aircraft fuselage and the human body where it is known to disrupt the healthy function of cells.

At this point, there is only limited advice from scientists. They say that during solar flares, when radiation exposure can multiply a hundred times, (i.e., a New York to London flight can then equal a hundred chest X-rays) pregnant women should not fly.

PASSENGER PRECAUTIONS

• If you are pregnant and planning to fly, call or log on to the Space Environment Center for up-to-date information on solar flares. <303/ 497-3235, www.sec.noaa.gov>. If there is excessive radiation, the phone message will say, "A solar particle event has occurred." The event can last from a couple of days up to a couple of weeks.

• If you have time to plan your trip, choose flights at lower LATITUDES because flights over the polar regions sustain double the radiation as flights over the equator. In other words, the Los Angeles-London nonstop has more radiation than the flight which transits New York.

• Again, if you have time to plan, choose flights at lower ALTITUDES because radiation doubles every 6,500 feet (2,000 meters).  Specifically, the jets which fly at higher altitudes are the ones usually found on the long-range routes: the Concorde, Boeing 747SP, Boeing 747-400, Boeing 767-300ER, Airbus A340-200, and MD-11.

FREQUENT FLYERS

Airline crews (pilots and flight attendants) receive the equivalent radiation per year that workers in nuclear power plants get. 

A 1995 study in Finland on international flight attendants and cancer found that flight attendants are two times more likely to contract breast cancer than women who do not fly regularly, and that in-flight radiation is likely the cause.