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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 the 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 concerning this risk and I 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 home owners and by inspectors during real-estate transactions. These short term tests are very misleading and often inaccurate. In fact, because radon gas levels can regularly go up and down for a variety of reasons, having a home checked for radon with short term monitoring or testing may, at best, be a waste of money.

Here are some of the reasons why short term, real-estate type radon tests cannot be trusted:

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 have turned off 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 area of a home, thereby temporarily increasing radon levels during the test period and consequently thwarting short term test results. Similarly, if the ground is 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 more important “average level” would be at any other time of year. 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. This negative air pressure 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

Just as deceptive as false highs are false lows. 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.

I have met buyers that have purchased homes under these circumstances, believing their house is safe. The level may have only been 2 pCi/L when tested before the purchase; 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.

The only way results of a short term test could be trusted (assuming there was value to short term testing), is if the conditions were constantly policed by the party seeking the information. However, 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 home buyers, home sellers 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 reduce our exposure to, but these 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 tests, as well as, the sale of mitigation equipment sold as a result of these tests. Unfortunately, many 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 affects of long term exposure. Consequently, real-estate transactions can become unnecessarily complicated and sometimes fall through altogether. Home buyers make decisions based on fear of radon rather than knowledge. Tests that reveal radon levels higher than the action level often result in either the seller or the buyer purchasing a mitigation system for perhaps $1,000.00 up to $3,000.00 depending on the home. These are often premature judgment purchases and sometimes totally unnecessary. Even worse, the constantly running radon evacuation fans can contribute to negative air pressure in a home. This negative air pressure can lead to more dangerous health and safety problems with 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 all of the negative aspects of the scare tactics and hype used to market short term tests.

My company offers short term tests only for situations when relocation companies (for lack of knowledge) require them. I never recommend them to clients because the information derived is essentially irrelevant.

Short Term Testing vs. Long Term Monitoring

There are most certainly valid concerns over the cancer risk caused by radon exposure and 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 the “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 to the long term health risks.

Fortunately, obtaining beneficial, long term data is now possible for home owners through the use of an affordable, continuous radon “monitor”. They 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 push of a button, you can derive long term averages which represent the actual health risk. If you tried to derive this same information with repeated short term tests, it could cost a fortune.

These devices are simple to use. Just plug them into an outlet on the lower level of the house 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 sounds each hour to let you know.

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 before investing into a mitigation system. If the long term average level remains low throughout the entire year, be glad and give the monitor to someone else you care about.

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)

Now…after having explained all of this, I should let you know that I do in fact do radon testing when necessary. Typically radon testing is required by some corporations and relocation companies as a formality in order for a real estate transaction to be processed. Though I do not agree with it, I will perform this service to help facilitate a real estate transaction.

This 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 the fast results needed during real estate transactions. Travel fees apply for the second trip to the property to pick up or drop off the test canisters before or after the general home inspection.

The fee for this service is $225.00 when performed concurrent with a general home inspection.

If health is the most important issue and a real estate transaction is not, remember that you can own your own monitor for only $129.00 and they will yield more information for a longer duration of time.

Radon monitors are user friendly. Just plug them into an outlet in the lower level of the house 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.

by Building Inspector and Indoor Air Specialist, Dan Schilling
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