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Radon is a naturally-occurring radioactive gas that results from the normal decay of uranium in rocks and soil. Like many gases, it is invisible; it is also odorless and tasteless. Radon seeps through the ground and into the air and, in some areas, it dissolves in the groundwater.

Radon gas formed in the ground can be very concentrated.  Once it gets into the earth’s atmosphere, it dilutes and exists at very low levels. However, the concentrated gas can enter homes through cracks in the foundation, gaps in walls or insulation, and through the water supply. It can also be released from building materials. Indoors, particularly in well-insulated homes, the radon gas can become trapped and build to high levels.

As radon decays, it gives off minute radioactive particles. It is these particles that have been shown to damage the lungs and lead to lung cancer. According to the National Cancer Institute, radon is the second most common cause of lung cancer, though it represents a far smaller risk than cigarette smoking—the leading cause of lung cancer.

Radon in the Home

The Environmental Protection Agency (EPA) recommends taking action if the indoor radon level reaches 4 picocuries per liter (pCi/L) of air or more. The average indoor radon level is approximately 1.3 picocuries per liter (pCi/L); about 0.4 pCi/L of radon is normally found in the outside air.

Radon Testing

Home radon test kits are widely available online and in home improvement stores. Short term detectors measure radon levels over the course of two to 90 days; long term detectors measure levels for as much as a year. Short-term kits are relatively inexpensive, and some states offer them for free. While kits vary, they consist of a collector, instructions for use, and information on where to send the kit for analysis. The cost for analysis is generally included in the kit’s price. Instructions are included with each kit; once the test period is complete, the user then sends the collector to the testing laboratory for analysis.

Radon levels fluctuate due to a number of seasonal and climatic influences. If your home radon kit’s result is 4 pCi/L or higher, you should contact your state radon office and schedule a follow-up long-term test for a better understanding of your year-round average radon level.

Reducing Radon Levels

Acting to lower the amount of radon is called “mitigation.”

The five principal ways of mitigating the amount of radon in your home are:

Your state radon office can provide you with a list of licensed radon mitigation specialists who will advise on how best to mitigate your specific situation.

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