Radon Risk Information

Radon is the second leading cause of lung cancer, after smoking. The US EPA and Surgeon General strongly recommend taking further action when a home's radon test results are 4.0 pCi/l or greater. The concentration of radon in the home is measured in picocuries per liter of air (pCi/l). Radon levels less than 4.0 pCi/l still pose some risk and in many cases may be reduced. If the radon level in the home is between 2.0 and 4.0 pCi/l, the EPA still recommends that you consider fixing the home. The average indoor radon level is estimated to be about 1.3 pCi/l; roughly 0.4 pCi/l of radon is normally found in the outside air. The higher the home radon level, the greater the health risk. Even homes with very high radon levels can be reduced to below 4.0 pCi/l and many homes can be reduced to 2.0 pCi/l or less.

Understanding Time-Sensitive Testing Protocols

Continuous Monitor Results: Single test result average 4.0 pCi/l or more. Fix the home.

Single test result average between 2.0 and 4.0 pCi/l. Consider fixing the home.

Less than 4.0 pCi/l: confirm the low result by testing again at least every two years and whenever significant changes to the home structure or mechanical systems occur.

Test during different seasons and different weather conditions to reduce your risk of exposure.

For more information, please check EPA website ( or contact the author:

Wenwei Yao

Inspek Home Inspection, LLC
Home Inspection and Radon Test

Tel: 240-784-6645; 240-217-0245


Last update: 03/22/2015