Home Inspections: Radon Testing
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WHAT IS RADON?
Radon is a naturally occurring radioactive gas, which has always been a part of our environment. It's a natural decay product of uranium and is found in soil everywhere in varying concentrations.
Radon gas can accumulate in enclosed places, such as a house, but its presence, even in high concentrations, cannot be detected by human senses because the gas is invisible and has no odor. Long term or chronic exposure to radon has been linked to lung cancer. The greater the concentration and the longer a person is exposed, the greater the risk, so all people are encouraged to reduce their exposure. However, because of its physical characteristics, the only way to detect the presence of radon gas and measure the level is by a test. So people wanting to limit their exposure must first conduct a test to determine what their exposure levels are.
Radon can move easily through soil and tiny cracks in rock. When it reaches the surface of the soil, it disperses and is diluted to very low levels in the outdoor environment. However, when the gas moves upward through soil beneath a home, it may enter through cracks or other openings in the foundation and build up to unacceptable levels.
The higher the levels of radon gas in a home, the greater the amount inhaled. Just as radon is produced from the decay of radioactive materials, it further decays producing new radioactive materials in the form of solids. These radon decay products can attach to other particles, such as dust and cigarette smoke, which can be inhaled and become trapped in the lungs where they emit radiation. These decay products can damage lung tissue and increase the risk of developing lung cancer. The risk of lung cancer from a given exposure to radon is greater for a smoker than a non-smoker.
Lung cancer is the only known health effect linked to radon exposure at this time. The EPA estimates that between 15,000 and 22,000 of the 125,000 annual deaths from lung cancer may be attributable to radon exposure. In New Jersey, of the annual 4,700 lung cancer deaths, as many as 140-250 may be associated with radon exposure. These estimates of cancer risk from radon exposure are less than those caused by smoking, but are far greater than the number of cancers estimated to occur as a result of exposure to other environmental hazards, such as toxic chemicals in drinking water or pesticide residues on food.
Radon Risk for Smokers and Nonsmokers
(Source: National Academy of Sciences, Biological Effects of Ionizing Radiation,
Sixth Report, 1998)
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Radon Level (in pCi/L)
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Odds for non-smokers* of developing lung cancer due to radon if exposed to this level over a lifetime
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Odds for smokers* of developing lung cancer due to radon if exposed to this level over a lifetime**
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20
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1 in 27
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1 in 5
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8
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1 in 68
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1 in 13
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4
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1 in 135
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1 in 26
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2
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1 in 270
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1 in 52
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0.4***
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1 in 1,350
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1 in 260
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*Smokers are defined as individuals who have smoked at least 100 cigarettes in a lifetime; non-smokers have never smoked or smoked less than 100 cigarettes in a lifetime.
**This is in addition to the risk of lung cancer from smoking itself.
***Average outdoor radon concentration.
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TESTING IS ONLY WAY TO DETERMINE IF THE HOUSE HAS HIGH LEVELS OF RADON GAS. TESTING IS INEXPENSIVE AND EASY TO PERFORM.
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New Jersey Radon Map
What types of tests can be use to test the house?
Short-term Tests
A single short-term test of 2-7 days in length can be used to indicate the radon level in your home. If a single short-term test reveals levels of 4 pCi/L or more, DEP data indicate that subsequent testing would confirm that levels in the home are 4 pCi/L or more in 80% of cases. If a second short-term test is conducted in the same location (either simultaneously or at different points in time), and the results of the tests are averaged, the average will provide a slightly more accurate estimate of radon levels. A variety of short-term test devices are available, including charcoal canisters, electrets, and continuous radon monitors. The DEP Radon Section considers all short-term test devices used by certified companies to be equally reliable
Long-term Tests:
A long-term test of 3-12 months will provide your best estimate of average exposure over time, since radon levels fluctuate daily and by season. Because gases are drawn to areas of lower pressure, radon gas will enter the home at a rate that depends on the air pressure inside the home, which is affected by temperature, wind conditions, exhaust systems in the home, etc. Long-term testing should include the winter months, when radon concentrations are often higher than at other times. Long-term test devices are usually either alpha track detectors or electrets; both tests are considered equally reliable and accurate.
What should I know about radon testing within a home?
A single short-term radon test may be used for real estate transactions. An escrow account, with funds set aside by the seller, can be arranged for the buyer who prefers to test after closing. The funds can then be used to mitigate the home if testing reveals concentrations of 4 pCi/L or more.
If you are a potential homebuyer and are concerned about the possibility of test tampering, discuss anti-tampering methods with the radon measurement contractors you are considering hiring. Also, be sure to check that the contractor will close and pick up the test, as required by regulation. Neither the buyer, the homeowner nor the real estate agent can perform any part of the test, including: closing the test, picking it up, or sending it to a laboratory
The DEP and the Environmental Protection Agency (EPA) both recommend that you take action to mitigate your home if your test results indicate radon levels of 4.0 pCi/L of radon or more. If you used two or more short-term tests at the same location, the results should be averaged.
What kind of mitigation system is needed?
The most common type of radon mitigation system is the sub-slab depressurization system. This system uses venting and sealing to lower radon levels in the home. A pipe is installed that runs from below the basement flooring to above the roofline, with a fan at the top that draws radon out from under the slab. Cracks and openings in the foundation are sealed. The radon is vented through the pipe to the outside, where it is quickly diluted.
How is a mitigation system installed in the home?
Have a New Jersey DEP certified radon mitigation company to do the work for you. New Jersey certified radon mitigation professionals meet specified education and experience standards and must take continuing education classes each year to maintain their certification. It is against the law for uncertified contractors to do mitigation work in New Jersey.
After your home has been mitigated, make sure the mitigator does a post-mitigation test to prove the system is working properly. In addition, you can contact the Radon Section to obtain a free post-mitigation test (you will have to provide a copy of your mitigation contract). Retesting your home every two years will tell you whether or not your system is still working effectively in reducing the radon level to below 4 pCi/L. If you believe that your system was not installed correctly, you can contact the Radon Section to arrange for a free inspection and test of the system.
Learn more about radon from following links
www.epa.gov/radon
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