What is radon?

Radon, a cancer-causing radioactive gas, comes from the natural breakdown of uranium in the soil, rock, and water and is found throughout the United…

What is radon?

Radon, a cancer-causing radioactive gas, comes from the natural breakdown of uranium in the soil, rock, and water and is found throughout the United States. You can not see, smell, or taste radon. But it may still be a problem in your home. When you breathe air containing radon, you increase your risk of getting lung cancer. In fact, the Surgeon General of the United States has warned that radon is the second leading cause of lung cancer in the United States today.

How does radon cause lung cancer?

Radon emits radioactive alpha particles which can deliver large jolts of energy. When these radioactive particulates are inhaled, these bursts of energy can damage the cells’ DNA which can ultimately lead to cancer.

The National Academy of Sciences confirms that radon is the second-leading cause of lung cancer. An estimated 15,000 to 20,000 deaths per year are attributed to radon-related lung cancer.

Why should I test for radon?

Any home can have a radon problem. This means new and old homes, well-sealed and drafty homed, and homes with or without basements. In fact, you and your family are most likely to get your greatest radiation exposure at home. That is where you spend more of your time.

Nearly one out of every 15 homes in the United States is estimated to have an elevated radon level. Elevated levels of radon gas have been found in homes in your state. Contact your state radon office for information about radon in your area.

“Indoor radon gas is a national health problem. Radon causes thousands of deaths each year. Millions of homes have elevated radon levels.”

How do I test for radon and what type of results should I expect?

Radon testing is easy. Since you cannot see or smell radon, special equipment is needed to detect it. When you’re ready to test your home, you can order a radon kit by mail. The most common types of radon testing devises are listed below.

Passive Devices

Passive radon testing devices do not need power to function. These include charcoal canisters, alpha-track detectors, charcoal liquid scintillation devices, and electret ion chamber detectors. These devices are exposed to the air in the home for a specified period of time and then sent to a laboratory for analysis.

Active Devices

Active radon testing devices require power to function. These include continuous radon monitors and continuous working level monitors. They continuously measure and record the amount of radon or its decay products in the air. Many of these devices provide a report of this information which can reveal any unusual or abnormal swings in the radon level during the testing period. A qualified tester can explain the final report to you. Although these tests may cost more, they may ensure a more reliable result.

Length of Time to Test:

Short-term tests remain in your home from two to 90 days, depending on the device. All radon tests should be taken for a minimum of 48 hours. Some devices require a longer minimum length of time. Read and follow the manufacturers instructions.

Long-term tests remain in your home for more than 90 days. A long-term test results is more likely to tell you your home’s year-round average radon level than a short-term test.

Certain precautions should be followed to avoid interference during the test period:

    • Close doors and windows 12 hours before testing


    • Do not conduct short-term tests during severe storms or high winds


    • Follow the testing instructions and record the start time and test date


    • Place device at least 20 inches above the floor in an area where it will not be disturbed


    • Place the device away from high heat, high humidity, and exterior walls


    • Leave the device in place for as long as the test instructions say


  • Once the test is finished, record the stop time and date, reseal the package and return it immediately to the lab for analysis.

Test Results

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 U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels. While this goal is not yet technologically achievable for all homes, radon levels in many homes can be reduced to 2 pCi/L or less.

Your radon test results may be reported in either picocuries per liter of air (pCi/L) or working levels (WL). If your test result is in pCi/L, the EPA recommends radon levels below 4 pCi/L. If your test results are in WL, the EPA recommends radon levels be below 0.02 WL.

My test results showed a high level of radon. What should I do now?

Some radon reduction systems can reduce radon levels in your home by up to 99%. The cost of making repairs to reduce radon levels depends on how your home was built and other factors. Most homes can be fixed for about the same cost as other common home repairs, like painting or having a new water heater installed. The average cost for a contractor to lower radon levels in a home can range from $1,000 to $3,000.

A variety of methods can be used to reduce radon in homes. Sealing cracks and other openings in the foundation is a basic part of most approaches to radon reduction. EPA does not recommend the use of sealing alone to limit radon entry. Sealing alone has not been shown to lower radon levels significantly or consistently.

There are several methods that a contractor can use to lower radon levels in your home. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. EPA generally recommends methods which prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from below the house and venting it through a pipe, or pipes, to the air above the house where it is quickly diluted. These “sub-slab depressurization” systems do not require major changes to your home. Similar systems can also be installed in homes with crawl spaces. These systems prevent radon gas from entering the home from below the concrete floor and from outside the foundation. Radon mitigation contractors may use other methods that may also work in your home.

Sealing cracks and other openings in the foundation is a basic part of most approaches to radon reduction. Sealing the cracks limits the flow of radon into your home thereby making other radon reduction techniques more effective and cost-efficient. It also reduces the loss of conditioned air. EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently. It is difficult to identify and permanently seal the places where radon is entering. Normal settling of your house opens new entry routes and reopens old ones.

Some natural ventilation occurs in all houses. By opening windows, doors, and vents on the lower floors you increase the ventilation in your house. This increase in ventilation mixes outdoor air with the indoor air containing radon, and can result in reduced radon levels. However, once windows, doors and vents are closed, radon concentrations most often return to previous values within about 12 hours. Natural ventilation in any type of house should normally be regarded as only a temporary radon reduction approach because of the following disadvantages: loss of conditioned air and related discomfort, greatly increased costs of conditioning additional outside air, and security concerns.

Increase fresh air ventilation while controlling humidity levels. A positive pressure can be created in the home by using mechanical ventilation system such as the DVA. Increased ventilation will help to dilute the contaminants in the home, including radon. Increasing the amount of fresh air entering the home may also increase the moisture level of the home. When using mechanical ventilation, it is imperative to have a humidity control system in place.

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