Radon is a tasteless, colorless and odorless gas that is a decay product of uranium and occurs naturally in soil and rock. Radon breaks down into components called radon progeny, sometimes called "radon daughters," which emit high-energy alpha particles. These emissions raise the risk of lung cancer.
The main source of high-level radon pollution in buildings is surrounding uranium-containing soil such as granite, shale, phosphate and pitchblende. Radon enters a home through cracks in walls, basement floors, foundations and other openings. It may also contaminate the water supply, especially in private wells.
A level of four picocuries per liter (pCi/L) of air has been identified by the U.S. Environmental Protection Agency as an annual average for homes and schools at which remedial action should be taken. The National Council of Radiation Protection recommends a level of no more than 8 pCi/L indoors.
It has been estimated that approximately one third of radon-induced lung cancer could be avoided if homes with radon concentrations exceeding the EPA action level underwent changes to reduce radon concentrations to below that level. However, eliminating all radon exposure is not possible.
Elevated levels of radon have been identified in every state. An estimated eight million homes in the United States are estimated to have elevated levels of radon.
It is estimated that between 10 percent and 14 percent of lung cancer deaths in the United States could be attributed to radon. Most of the radon-related lung cancers occur among smokers. However, an estimated 2,900 of the 21,000 deaths from lung cancer among nonsmokers in the United States each year are estimated to be radon-related.
It is possible for one home to have elevated levels of radon while a neighboring home does not. Testing is the only way to determine levels of radon in a structure. Testing can be done through do-it-yourself home test kits or through a professional testing firm.
Home test kits labeled "meets EPA requirements" should be used. Both long-term and short-term tests can be done.
Short-term tests remain in the home for two to 90 days, depending on the device. "Charcoal canisters," "alpha track," "electretion chamber," "continuous monitors," and "charcoal liquid scintillation" detectors are the most common short-term testing devices.
Long-term tests remain in the home for more than 90 days. "Alpha track" and "electret" detectors are commonly used for this type of testing. A long-term test gives a more accurate annual average radon level than a short-term test, because radon levels vary day to day and season to season.
Radon levels can be lowered through a variety of repairs, from sealing cracks in floors and walls to changing the flow of air into the building.
Sub-slab depressurization uses pipes and fans to remove radon gas from beneath the concrete floor and foundation before it can enter the building. Radon is vented above the roof, where it safely disperses.
Repairs to decrease radon levels should be made by an EPA or state-certified contractor.
My source for this week was www.lungusa.org and http://epa.gov/radon/healthrisks.html