National average domestic exposures are
of approximately 1.3 pC/L indoors. Some level of radon will be found in
Radon mostly enters a home directly from the soil through the lowest
level in the home that is in contact with the ground. Typical entry points of radon into homes are cracks in solid
foundations, construction joints, cracks in walls, gaps in suspended
floors, gaps around service pipes, cavities inside walls, and the water
supply. Radon concentrations in the same location may differ by a factor of two
over a period of 1 hour. Also, the concentration in one room of a
building may be significantly different from the concentration in an
adjoining room. Radon levels in the Midwest are typically much higher than the national average. Iowa and southern Minnesota have some of the highest exposure rates in the nation.
Mitigation systems use the existing sump pump basin, PVC and a fan running 24/7 to remove the gas being formed under the house. The fans can be located on the exterior or attic of the home and are nearly silent. If the sump basin is not located in a useable area, another hole can be drilled to provide access to the drain tile.
Back in 1900, radon was the fifth radioactive isotope to be discovered.
The presence of radon in indoor air was documented as early as 1950.
Beginning in the 1970s research was initiated to address sources of
indoor radon, determinants of concentration, health effects, and
approaches to mitigation. In the United States, the problem of indoor
radon received widespread publicity and intensified investigation after a
widely publicized incident in 1984. During routine monitoring at a
Pennsylvania nuclear power plant, a worker was found to be contaminated
with radioactivity. A high contamination of radon in his home was
subsequently identified as responsible for the contamination.
EPA: "A Citizen's Guide to Radon"
The Environmental Protection Agency's guide to protecting yourself and your family from radon.
EPA: Maps of radon zones
. An indication of the potential radon levels in your home.