Periodically we see or read news reports about radon. You may even have purchased or sold a house recently and had your home inspector offer radon testing. In talking with customers, I find that very few people understand radon and its risks. Despite the periodic news reports, some people have never heard of radon. The following is an attempt to clarify the issues surrounding radon.

What is radon?

Radon is an odorless, tasteless gas that is a by-product of the breakdown of radioactive material in the soil. The amount of radon in soil varies by soil chemistry. The amount of radon that escapes from the soil depends on soil moisture and porosity as well as the pressure of a house relative to the soil.

Is radon harmful?

According to the Environmental Protection Agency's 2003 "Assessment of Risks From Radon in Homes," approximately 21,000 lung cancer deaths per year are attributable to radon exposure.

Is there radon in Georgia?

The EPA publishes a map of radon zones. In this map, counties are rated for their potential for high radon levels. There are three rating categories: highest potential, moderate potential and low potential. Fifty-five counties in North Georgia are rated for moderate potential. Four counties are rated for high potential. These counties are Cobb, Fulton, DeKalb and Gwinnett. Most of the state, all in the southern half, is rated for low potential.

How do I find out if I have radon?

There are numerous devices for screening radon levels in homes. Some devices are available at hardware and home improvement stores. You also may choose to have a qualified professional test your home. The EPA protocol requires that radon testing devices remain in the home for a minimum of 48 hours for a short-term test. Long-term tests are a minimum of 90 days. Testing devices must be placed in the lowest lived-in level of the home. More detailed instructions for placement will be included with the device. The home should be maintained in a closed condition (normal passage in and out of the home is acceptable) just before and during the test. Radon is measured in picoCuries per liter of air, pCi/L. The EPA action level is 4.0 pCi/L. At or above 4.0 you should either retest or fix your home.

How do I fix my home?

The basic fix or mitigation procedure for radon is a pipe with a low volume fan at the top. Simply, the pipe draws the radon from the soil and discharges it to the exterior of the house before it migrates into the living areas of the house. Radon mitigation must be performed by qualified professionals. Qualified radon testing and mitigation contractors can be found by contacting either the National Environmental Health Association at 1-800-269-4174, www.neha-nrpp.org, or the National Radon Safety Board at 1-866-329-3474, www.nrsb.org.

Do you have a home repair question? Send e-mail to Ask the Inspector at H&G@ajc.com. Our expert, Bill Garwood, spent 15 years as a building contractor before becoming a home inspector. He is part owner of a residential inspection firm and a firm providing training in building inspection and codes.