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General Questions
Testing Air for Radon
Mitigating Radon Problems
General Questions
What is radon?
Radon is a radioactive gas. You can't see it, you can't smell it, and you can't taste it. The only way you'll know if it's present is if you test for it.
Radon is formed by the natural radioactive decay of uranium in rock, soil, and water. Naturally existing, low levels of uranium occur widely in the Earth's crust. Once produced, radon moves through the ground to the air above. Some remains below the surface and dissolves in water that collects and flows under the ground's surface.
When radon begins to decay, it emits ionizing radiation in the form of alpha particles. It also produces short-lived decay products, often called progeny or daughters, some of which are also radioactive.
Unlike radon, the progeny are not gases and can easily attach to dust and other particles. Those particles can be transported by air and can be inhaled.
The decay of progeny continues until stable, non-radioactive progeny are formed. At each step in the decay process, radiation is released.
What health effects are associated with radon exposure?
The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States and second only to smoking in the diagnosis of lung cancer. If you smoke and you are exposed to elevated radon levels, your risk of lung cancer is considerably higher.
Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these particles release small bursts of energy. This can damage lung tissue and lead to lung cancer over the course of your lifetime. Not everyone exposed to elevated levels of radon will develop lung cancer and the amount of time between exposure and the onset of the disease could be many years.
What is the "acceptable" level of radon in air?
The EPA recommends that a home be mitigated if an occupant's long-term exposure will average 4 picocuries per liter (pCi/L) or higher.
What is a "picocurie" (pCi)?
A pCi is a measure of the rate of radioactive decay of radon. One pCi is one trillionth of a Curie, 0.037 disintegrations per second, or 2.22 disintegrations per minute. Therefore, at 4 pCi/L (picocuries per liter, EPA's recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period.
How does radon get into a building?
Most indoor radon comes into the building from the soil or rock beneath it. Radon and other gases rise through the soil and get trapped under the building. The trapped gases build up pressure. The air pressure inside a home is usually lower than the pressure in the soil. Therefore, the higher pressure under the building forces gases though floors and walls and into the building. Most of the gas moves through cracks, joints, gaps, crawlspaces and other openings. Once inside, the radon can become trapped and concentrated. Outdoor air that is drawn into a building can also contribute to the indoor radon level. The average outdoor air level is about 0.4 pCi/L, but it can be higher in some areas. While radon problems may be more common in some geographic areas, any home may have an elevated radon level. New and old homes, well-sealed and drafty homes, and homes with or without basements can have a problem. Homes below the third floor of a multi-family building are particularly at risk.
Testing Air for Radon
Why should I test my home for radon?
Because radon is widely believed to be the second leading cause of lung cancer. The EPA and the Surgeon General recommend testing for radon in all homes below the third floor. Radon has been found in homes all over the United States and knows no boundaries so any home can have a radon problem. On average, one out of every fifteen homes in the United States has a problem and the only way to know whether you have it in your home or not is to test for it.
What kinds of test devices are used?
At KNOW RADON we use active continuous radon monitors that integrate hourly. This is a continuous monitor that is placed by a licensed professional. These monitors take hourly radon readings, (over 48 hours), and stores them in memory for printing later. The benefit of using a continuous monitor is that it gives immediate results at the end of the test versus charcoal canister and bags that must be mailed off for analysis. Continuous Test Monitors must be re-calibrated on a yearly basis at their respective manufacturer.
Where should home testing be done?
Proper short term testing is dependant on correct placement and conditions with in the home during the test. Closed house conditions are a MUST! All windows and doors must be closed, (except normal entry and exit), a minimum of 12 hours before and during testing. The EPA recommends that testing be done in the lowest level of the home suitable for occupancy. This typically represents an area where greatest radon levels may occur.
What do I do if a test result is less than 4 pCi/L?
If the result of an initial test measurement is below 4 pCi/L, a follow-up test is not necessary. Because radon levels change over time, you will want to retest every couple of years, especially if use patterns change or perhaps a lower level of the building becomes occupied or used more frequently. Renovations, changes in ventilation, earthquakes, settling of the ground beneath the building, and other changes may cause indoor radon exposures to change.
What do I do if a test result is 4 pCi/L or higher?
The EPA has stated that in order for a home to be deemed safe, the radon levels should not exceed 4 pCi/L. You may want to consider a follow-up test should your test results come back slightly elevated in order to confirm whether radon levels are high enough to warrant mitigation. If the average of the initial test and the second test results are equal to or greater than 4 pCi/L, then radon mitigation is highly recommended. If the average of the two tests results are less than 4 pCi/L, consider testing again sometime in the future.
Mitigating Radon Problems
What is a radon mitigation system?
A radon mitigation system is any system or steps designed to reduce radon concentrations in the indoor air of a building. The EPA recommends that you take action to reduce your home's indoor radon levels if your radon test results are 4 pCi/L or higher.
What are the benefits of radon mitigation?
Radon reduction systems are very effective and have been known to reduce radon levels by as much as 98%. If you are considering selling your home you will want to consider testing and/or mitigating a radon problem before making your final preparations.
How much does it cost to reduce radon in an existing home?
If a home is found to have elevated radon levels, the average cost to install a radon mitigation system can run anywhere from $800 to $2,500 depending on the size of your home and many other factors. The average cost to install radon-resistant features in a new home during construction is $350 to $600.
Will any more testing be required after a radon mitigation system has been installed?
Yes! A radon test should be conducted no more than 24 hours and no less than 30 days after installation of your mitigation system. This is to insure that the radon reduction system is effectively operating. Be sure the system is operating during the post-mitigation radon test.
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