You cannot see them, but radio waves pervade your peaceful living space. They emanate from an increasingly large menagerie of electronic gadgets, appliances and satellites. FM radio and broadcast television have been around for years; more recently, cell phones and Wi-Fi routers have added their high frequencies to the mix.

Should we worry? In May the International Agency for Research on Cancer declared that long-term cell-phone use could “possibly” cause cancer; it says the same for coffee drinking. The intensity of exposure is proportional to distance, and cell phones are held close to the brain, but many studies conclude that evidence of a cancer link is nonexistent.* The sheer number of radio-frequency sources is not a concern either. Exposures “do not all add collectively at any one point in space,” says Jerrold T. Bushberg, head of health physics programs at the University of California, Davis. And average exposure is still far below safety standards, which have a large margin built in.

*Clarification (8/17/11): In a general discussion about electromagnetic radiation, we wrote that "the intensity of exposure is proportional  to distance." We simply meant that exposure varies with distance, but should have used the generic "varies" instead of the mathematical "proportional," because as several readers pointed out, intensity is inversely proportional to the square of distance.

— Mark Fischetti

» Learn more about radiation, cell phones and electromagnetic bombardment in the August 2011 Graphic Science Web Exclusive


Graphic by Jude Buffum; Source: Federal Communications Commission