Measuring radon with testing kits that sit in a house for just a few days can yield misleadingly low values in summer, a new study finds.
Alabama maintains a statewide database of 36,000 domestic measurements of radon, a radioactive gas emitted by rocks in soil. Although these data revealed some geographical hot spots, radon readings in such areas were often unexpectedly low if testing had occurred in summer.
To investigate a possible seasonal bias, James L. McNees of the Alabama Department of Public Health in Montgomery and Susan H. Roberts of the Alabama Radon Education Program at Auburn University offered free radon-test kits to state residents whose homes had recently undergone summer testing.
Of the 186 homes resampled in winter, 63 percent exhibited higher radon values than they had in summer. Indeed, 27 percent of these homes revealed air concentrations more than five times the 4-picocuries-per-liter federal guideline for taking remedial action. The researc