Home Radon Levels

Radon is a radioactive gas produced by natural sources in our environment. You cannot smell it, see it or taste it. It is a dangerous home intruder, causing 21,000 deaths in the United States every year, according to a United States Environmental Protection Agency report in 2003. Traces of uranium and radium in soil and rocks produce radon. The gas leaks through your foundation or diffuses into your water, then builds up inside your home.

Hazard Levels

You can test the air in your home for radon with a test kit. A September 2008 report in "Consumer Reports" found some good home kits for $30, but said professional testing may be more accurate.
The January 2009 EPA radon guidelines describe indoor air danger levels and best testing practices. If radiation is detected at 1.3 picocuries per liter -- expressed as pCi/L -- of air, EPA estimates such levels may cause two lung cancer cases in every 1,000 people exposed. EPA warns that more than 2 pCi/L, about twice the level the U.S. Geological Survey considers average, warrants remediation.

Ground Sources

Soil radon seeps through your foundation into your home. Scientists at the USGS say your local geology may be either high or low in traces of uranium and radium. This variability makes prediction less reliable than testing for home radon levels. Radon in the pores and air spaces within your soil can range from 20 pCi/L to more than 100,000 pCi/L, with the U.S. average between 200 and 2,000 pCi/L.

Water Sources

If you draw your water from a deep well, the EPA states you may be drinking radon produced in deep rock strata. They estimate about 168 cancer deaths every year are caused by lifetime use of well water. About 18 to 20 of those will be from stomach cancer, with the rest being from lung cancer caused by radon liberated into household air. The USGS estimates that ground water ranges from 100 to 3 million pCi/L.
You can treat your well water at your home's point of entry to render all your water safe. If you treat your water at the point of use, you'll need equipment at every tap.

Building Materials

Scientists at the USGS warn that your decorative granite counter tops, natural rock fireplaces or stone tile floors may all contain minute traces of uranium or radium, which continually break down by radioactive decay and add radon to your air. Building materials in your foundation also carry this risk. Not all natural products contain dangerous levels. Building-material suppliers can certify low-emission products. If your levels are already high, both EPA and USGS publish remediation information.

Smoke Detectors

Dr. Paul Frame, CHP, Ph.D., a radiation safety specialist with the Health Physics Society, published a report in 2002 responding to questions concerning the type of smoke detectors that contain the radioactive element americium-241. He assured users that these emit only minimal alpha radiation, and no radon. They will not skew radon testing results. He also recommends long-term rather than short-term home radon testing, because radon levels vary from day to day.