Although certain geographic areas are recognized as being at higher risk for radon, considerable differences were found among individual homes in a neighborhood, sometimes as close as the house next door. The U.S. Environmental Protection Agency publishes radon zone maps for the United States . Radon maps can also be acquired from state departments of environmental protection. Elevated concentrations of radon can be a significant source of radiation exposure in the home. The radioactive decay products of radon, not the gas itself, may be retained in the lungs and cause lung cancer.
Smokers are at an even higher risk of developing radon-induced lung cancer.
Control measures generally include a combination of ventilation, source removal or modification, and air purification.