Radon Gas Should you test or not?
by Building Inspector and Indoor Air Specialist, Dan Schilling
Radon is a naturally occurring, radioactive gas that comes up from the earth; it is invisible and cannot be smelled in the air. As it seeps up into homes, it can become trapped indoors in concentrated amounts and inhaled by occupants. Every major health organization provides serious warnings about the risk of lung cancer from exposure to radioactive radon gas in indoor air. As an air quality inspector, I agree with these organizations and believe that everyone should know whether they are being exposed to unsafe levels of radon.
What I do not agree with are the current methods being used to test for radon by homeowners and homebuyers during real-estate transactions. These short-term tests are often inaccurate and very misleading because they are merely a snapshot of time. Radon gas levels can regularly go up and down for a variety of reasons and having a home tested for radon with a short-term test or short-term monitoring is at best misleading and a waste of money.
Unreliability of Short-term Radon Tests
False High Levels
Houses that sit vacant for a little while almost always have elevated levels of radon. The same is true for homes where the owners do not regularly use their basement or lower level, or if they have restricted the ventilation in those areas to save energy. A home being lived in by a single person is more likely to yield a higher level of radon. Also, a heavy rain passing down through the earth can literally push radon gas up through the basement floor or foundation of a home, thereby temporarily increasing radon levels during the test period and consequently thwarting short-term test results. Similarly, if the ground is temporarily frozen at the time of the test, the radon cannot escape to the atmosphere outdoors. This condition can inadvertently yield test results much higher than the important “annual average.” Additionally, the operation of certain types of ventilation systems including air-to-air exchangers, clothes dryers and other exhaust fans, can cause negative air pressure within a home which can literally suck radon up out of the earth and into the home, which could temporarily raise levels during a short-term test.
False Low Levels
False low levels are just as deceptive. If a seller wants their home to sell and they know a radon test is being performed, they can easily thwart the test results after the inspector leaves. Sellers can deliberately use tricks with the ventilation system which could reduce test levels. Sellers can also open doors or windows to lower the results of a test. Sellers can even cover testing devices while the test is being conducted. Conditions would have to be constantly surveilled by the party seeking the information.
I have worked with clients that have purchased homes under these circumstances, believing their house was safe. The level may have only been 2 pCi/L when tested before the purchase but when reselling at a later date, they are shocked to discover that the level is now 16 pCi/L; four times higher than the government action level.
For these reasons, there is little value to short-term testing. Even people who take their own tests have a 50/50 chance of getting false positives or false negatives if they do not properly consider all the variables.
Inconvenienced Sellers, Buyers and Realtors
In my professional opinion, it is unfair to homebuyers, homesellers, and real-estate agents to be inconvenienced because of the results of a short-term radon test. Sellers become angry when test results come back high and their home sale falls through. Buyers sometimes run from houses that they, and often their real-estate agents, have spent much of their time trying to find. Yes, radon is a serious indoor air pollutant that we should avoid inhaling, but misleading and inaccurate short-term tests should have nothing to do with buying or selling a home.
Consequences of Short Term Testing and Mitigation Hype
Radon mitigation contractors and home inspectors are taught at seminars how to capitalize on the fear of radon. They can profit both from the marketing of the short term tests, as well as the sale of mitigation equipment sold as a result of these tests. Unfortunately, some home inspectors do not inform their clients of the likelihood of obtaining false results from short-term testing, nor do they explain the lack of relationship between a short test and the health effects of long term exposure.
Consequently, real-estate transactions can become unnecessarily complicated and sometimes fall through altogether. Homebuyers make decisions based on fear of radon rather than knowledge. Tests that reveal radon levels higher than the action level often result in the purchase of a mitigation system for $1,000.00 to $3,000.00. These purchases are premature and often unnecessary. Without secondary precautions, the constantly running radon evacuation fans can contribute to negative air pressure in a home which can lead to more dangerous health and safety problems than radon; problems such as the back-drafting of carbon monoxide from appliances such as furnaces, water heaters and fireplaces. Add to that the cost of running and maintaining these systems and you begin to realize the importance of accurate information.
Short-Term Testing vs. Long Term Monitoring
There are valid concerns over the cancer risk caused by radon exposure. People should indeed know what their home radon levels are; the question is how. Being that the health risk of lung cancer is directly proportional to “long-term” exposure to radon, a short-term test is not only questionable in its validity, but virtually meaningless in the scope of long-term exposure. Radon levels can spike up or down under such a variety of conditions that the results of a short-term test has no real bearing on the long-term health risks.
Fortunately, obtaining beneficial, long-term data is now possible for homeowners through the use of an affordable, continuous radon “monitor”. These monitors can typically be owned for less than the cost of just one short term test performed by a professional, and they provide truly helpful information. Helpful because the information is provided on a continual basis, 24 hours a day, all year long. Furthermore, with the simple push of a button, you can derive both short-term information to help,understand how a home performs and why, as well as long-term averages which more accurately represent the health risk. If you tried to derive this same information with repeated short-term tests, it would cost a fortune.
This new technology is simple to use. Just plug them into an outlet on the lower level of the home and your radon level will appear in the lit numbers on the front of the monitor. Monthly, seasonal and annual averages can be determined at the touch of a button. If radon levels exceed the safety action level, an audible chirping alarm will sound each hour to let you know.
When using the monitor, if the long-term average levels are higher than the government safety action levels, follow some of the common sense solutions offered in government literature and here at indoorair.com before investing into a mitigation system. If the long-term average level remains low throughout the variety of weather and building conditions encountered throughout the year, be thankful and let someone else you care about use the monitor for a year.
If you do install a system or already happen to have one, it is essential that you also have a make-up air vent installed in your home to protect the occupants from the consequences of negative air pressure. (See the article on Make-up Air)
While Residential Inspections does not recommend short-term testing, the tests are still provided when people or companies request them. Some corporations and relocation companies require the short-term tests as a formality in order for a real estate transaction to be processed.
The short-term testing service includes double canister placement to comply with EPA protocol, and includes direct delivery (not mail) of the samples to a local laboratory to obtain fast results often needed during real estate transactions.
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