What is Radon?
Radon is a gaseous radioactive element having the symbol Rn, the atomic number 86, an atomic weight of 222, a melting point of -71ºC, a boiling point of -62ºC, and (depending on the source, there are between 20 and 25 isotopes of radon - 20 cited in the chemical summary, 25 listed in the table of isotopes); it is an extremely toxic, colorless gas; it can be condensed to a transparent liquid and to an opaque, glowing solid; it is derived from the radioactive decay of radium and is used in cancer treatment, as a tracer in leak detection, and in radiography. (From the word radium, the substance from which it is derived.)
Sources: Condensed Chemical Dictionary, and Handbook of Chemistry and Physics, 69th ed., CRC Press, Boca Raton, FL, 1988.
Where does radon come from?
Radon-222 is the decay product of radium-226. Radon-222 and its parent, radium-226, are part of the long decay chain for uranium-238. Since uranium is essentially ubiquitous (being or seeming to be everywhere at the same time) in the earth's crust, radium-226 and radon-222 are present in almost all rock and all soil and water.
The amount of radon in the soil depends on soil chemistry, which varies from one house to the next. Radon levels in the soil range from a few hundred to several thousands of pCi/L (picocuries per liter) in air. The amount of radon that escapes from the soil to enter the house depends on the weather, soil porosity, soil moisture, and the suction within the house.
How does radon get into your home?
Any home may have a radon problem.
Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water (see www.epa.gov/radon/rnwater.html). In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.
MYTH: Scientists aren’t sure radon really is a problem.
FACT: Although some scientists dispute the precise number of deaths due to radon, all major health organizations (like the Centers for Disease Control, the American Lung Association and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non- smokers
MYTH: Homes with radon problems can’t be fixed.
FACT: There are simple solutions to radon problems in homes. Hundreds of thousands of homeowners have already fixed radon problems in their homes. Most homes can be fixed for about the same cost as other common home repairs; check with one or more qualified mitigators. Call your state radon office (www.epa.gov/radon/whereyoulive. html) for help in identifying qualified mitigation contractors
MYTH: Radon only affects certain kinds of homes.
FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements, homes without basements. Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.
MYTH: Radon is only a problem in certain parts of the country.
FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.