Radiation risk rises with polar air routes and ultra long-hauls

As a commercial airline pilot, Theresia Eberbach typically weighs several factors when deciding which trips to fly—the dates, destination and how long she’ll be away from home. Unlike most of her peers, Eberbach often has another variable to mull: How much radiation she’s willing to take.
 
Ionizing radiation is a permanent feature of the upper atmosphere, where the protection we take for granted on the surface is significantly thinner. At airlines’ cruising altitude, particles periodically ejected by the sun and cosmic radiation coursing through the universe are 100 times more potent than down below.
 
Still, the exposure for