Radon was for a time called niton, from the Latin nitens, shining, because in its early study the radioactive gas made phosphorescent materials glow, and it was also known simply as radium emanation, the exhalation of radium. The modern name ties it firmly to its radioactive parent. The element has no ancient or alchemical tradition, being a product of the discovery of radioactivity, and its cultural significance is almost entirely a matter of health: seeping from uranium-bearing rocks and soil, radon can accumulate in buildings, where it is a leading cause of lung cancer after smoking, so that testing and ventilating against this invisible, odourless gas has become a routine concern of modern homes and mines. Its glowing early name survives only as a historical curiosity.
In the United States the Environmental Protection Agency recommends corrective action in homes testing above four picocuries per litre of air, and the standard fix, sub-slab depressurisation, simply draws the gas from beneath a building's foundation and vents it safely above the roofline before it can seep indoors, a low-tech solution to a genuinely serious and entirely invisible health hazard. Radon testing kits are inexpensive and widely available, and public-health agencies in radon-prone regions routinely encourage homeowners to test every few years.