Although radon can’t be detected by the human senses, the proper equipment makes its relatively easy to detect. The EPA created a voluntary National Radon Proficiency Program (NRPP) that evaluated radon measurement companies ,and the testing services they offered until 1998. You can find a professionalradon serviceproviderin your area here.
One easy way to test for radon is with a do it yourself short-term radon test kit, available by mail order and many hardware stores, or you canhire anEPA qualifiedor state-certified radon measurement provider. The most common short-term tests are charcoal canisters, liquid scintillation detectors, alpha track detectors, electret ion chambers, and continuous radon monitors.
A short-term testing device is exposed to air in the home for 2 to 90 days, depending on the device used. Because radon levels are sporadic, and tend to vary from day-to-day and season-to-season, a long-term test is more likely to accurately measure the homes year-round average radon level than a short-term test. If results are needed quickly, a short-term test, followed by a 2nd short-term test can be used to determine the severity of the radon problem, and make a mitigation decision if needed.
Long-term test devices are exposed to the air in the home for more than three (3) months, but no longer than 1 year. Comparable in cost to the short-term tests, a long-term test is more likely to accurately indicate a home’s year round average radon level. Alpha track detectors and electret ion detectors are the 2 most popular long-term testing devices.
contain small amounts of activated charcoal. Radon and radon decay products are absorbed onto the charcoal, then measured by counting with a sodium iodide detector, or a liquid scintillation counter.
use a small sheet of plastic that is exposed for a period of 1 to 3 months. Alpha particles etch or the plastic sheet when they strike it. The marks are chemically treated, and can be counted in a laboratory to determine the radon concentration.
consist of an electro statically charged Teflon disk. Ions generated by the decay of radon strike the disk and reduce the surface voltage. The radon concentration can then be calculated by measuring the voltage reduction from the teflon disk.
are active devices that need power to operate. They require trained testers to be operated, and work by continuously measuring and recording the level of radon in the home. Typically they are used to conduct a 48 hour test, and in this case, it will record 48 readings that are 1 hour each, and provides the hourly readings along with a 2 day average.
During short term testing, doors and windows are closed twelve hours prior to testing, and these closed building conditions are required throughout the remainder of the testing period. Short term tests lasting 2-3 days should not be conducted during severe storms, or periods of unusually high winds.
The test is conducted in the lowest lived-in level of the home, a minimum of 20 inches above the floor, preferably in a room that’s used the most.
The test should not be located in a kitchen or bathroom where humidity levels or the an exhaust fan being operated could affect the credibility of the test. At the end of the test, the kit is then mailed to a lab for analysis; and results are mailed, and sometimes e-mailed back in a few weeks.
In some situations,like real estate transactions,state certified radon measurement providers conduct the radon test. The EPAs Home Buyers and Sellers Guide to Radon addresses the issue of real estate transactions.
If a short-term radon test results in 4 pCi/L or higher, there should be a follow-up test conducted to confirm the results. The Follow-up test can be either a long-term or a second short-term test. For a more accurate representation of the homes year-round average radon level, conduct a long-term test.
If follow-up results are needed right away, take a second short-term test. The higher the level of the first short-term test, the more certain the concerned party can be to conduct a second short-term test, rather than a follow-up long-term test. If the initial short-term test result is several times the action level for instance, 10 pCi/L or higher a follow up short-term test should be taken directly after, or as soon as possible.
If a long-term follow-up test results in a radon level of 4 pCi/L or higher, fix the home.
If the homeowner follows up with a second short-term test, the higher the test results, the more certain they can be that the home has a radon problem, and should be fixed. The homeowner should then consider fixing the home if the average of the first and second test is equal to 4 pCi/L or higher. The EPA recommends mitigating even if levels are between 2 pCi/L and 4 pCi/L, because a lot of times radon levels can be reduced to below 1 pCi/L and even though 4 pCi/L is the action level, there is no safe level of radon.
No radon level is safe. The risk getting lung cancer is directly proportional to the concentration and length of exposure to radon: the higher the concentration of radon, the higher the risk is to develop lung cancer. The basis for the 4 pCi/L Action Level is based on continually progressive mitigation technology.
Today, the mitigation technology can almost always reduce high radon levels to below 4 pCi/l, and to 2 pCi/L or lower around 70-80 percent of the time.
The average level of radon in homes is about 1.25 pCi/L. Even though Congress passed legislation in 1988 setting a national goal that indoor radon concentrations not exceed ambient outdoor radon levels (0.2-0.7 pCi/L), this goal is not yet achievable with the current mitigation technology.
Radon A Physicians Guide. EPA. Environmental Protection Agency, n.d. Web.
Source URL: http://www.epa.gov/radon/pubs/physic.html