RADON Information
Protect your family from RADON - test your home today!
Radon is a naturally occurring, radioactive gas formed by the breakdown of uranium. Radon is tasteless, colorless, and odorless, and is found in many types of soil and rocks. It can enter homes through cracks in foundations, sump pump crocks, crawl spaces, or other openings. Radon is present in outdoor air, but is diluted to such low levels that it is usually not a concern. However, inside an enclosed space (such as a home), radon can build up to dangerous levels. Any home can have a radon problem -- new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon poses a serious health threat to humans, especially to persons who are exposed to high levels for extended periods of time. Radon is classified by the Environmental Protection Agency (EPA) as a Class A carcinogen -- that is, one that is known to cause cancer in humans. Other Class A carcinogens include tobacco smoke, asbestos, and benzene. Radon is the second leading cause of lung cancer in the United States, resulting in approximately 21,000 lung cancer deaths each year. When radon gas is inhaled, it decays into radioactive particles that become trapped in your lungs. These radioactive particles can cause damage to lung tissue, and over time, this tissue damage can result in lung cancer.
Not everyone who breathes radon will develop lung cancer. Your chance of getting lung cancer from exposure to radon depends mostly on the following:
- How much radon is in your home
- How much time you spend in your home
- Whether you currently smoke or have smoked in the past
The EPA recommends that you take action to reduce the amount of radon in your home if your home has a radon level of 4.0 picocuries per liter (pCi/L) or higher. To put this level into perspective, an average outdoor level of radon is between 0.3 pCi/L and 0.7 pCi/L, and an average indoor level is approximately 1.3 pCi/L.
Since the late 1980's, radon tests have been taken throughout Michigan and the United States. The data was collected and compared to geological formations to generate the map below. Based on this information, about 12% of Michigan's single family, detached homes can be expected to have indoor radon levels greater than 4 pCi/L. But Zone 1 areas, including Washtenaw County, have a greater potential for elevated indoor radon levels. In some cases, more than 40% of the homes could have a radon problem. However, it is important to note that elevated radon levels have been found in homes in all three zones.
All homes should be tested for RADON, regardless of zone!
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Zone 1 - Highest Potential (greater than 4.0 pCi/L) |
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Zone 2 - Moderate Potential (2.0 pCi/L to 4.0 pCi/L) |
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Zone 3 - Low Potential |
Testing your home for radon is both easy and relatively inexpensive. Testing can be done with a do-it-yourself kit that you send back to a laboratory for analysis, or you can hire a professional to test for you. If you are willing to read and follow instructions, a do-it-yourself kit may be adequate. However, if you're involved in a real estate transaction, you may wish to hire a professional tester, as you will probably receive the results much faster. There are two main categories of radon tests: short-term tests and long-term tests.
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Short-term tests are used as a screening device to see if a home may have a radon problem. The tests generally run from 3 - 7 days, and must be conducted under "closed house conditions", where all doors and windows are kept closed except for normal entry and exit, and where exhaust fans and window air conditioning units are not being used. The most common and most readily available short-term test is an activated carbon (charcoal) device. This device may be a plastic or metal canister, a glass or plastic vial, or a paper pouch or envelope. Charcoal test kits can be purchased from most local hardware or home improvement stores.
Washtenaw County Planning & Environment has charcoal test kits available for $10 each, which includes the cost of postage and laboratory analysis. The test kits can be purchased at the Western County Service Center, located at 705 North Zeeb Road in Ann Arbor. Take I-94 to Exit #169 and head North on Zeeb Road. We are on the West side of the road past McDonald's, next to Scio Township Hall. For questions, call (734) 222-3869.
In addition, test devices called continuous radon monitors (CRMs) are available for short-term testing. These are electronic devices that require a power source such as an electrical outlet or internal battery, and a trained operator. CRMs are frequently used for measurements conducted in conjunction with a real estate transaction. The price of a CRM measurement typically ranges from $75 to $200.
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Long-term tests generally involve a device called an alpha track detector. This small plastic canister can be used for time periods ranging from 90 days to one year. It is a passive monitor (requires no power source), and is most often used as a year-long follow-up measurement when a borderline-high radon level has been found during a short-term test. The one-year measurement provides an estimate of your average annual exposure, giving you a better idea of what you are actually exposed to on a long-term basis. It allows you to measure the radon level under normal living conditions over a relatively long period of time, and as such, takes into account all the changes in weather that occur throughout the year, as well as the changes in the way you occupy/use your house under different weather conditions. Weather conditions and ventilation habits can influence the radon level in your house, and with this test you measure the way you actually live, opening and closing doors and windows any time you want, and using mechanical ventilation (furnace, air conditioner, exhaust fans, whole house fans, etc.) as you wish.
Washtenaw County Planning & Environment has Alpha-track detectors available for $20 each, which includes the cost of postage and laboratory analysis. The detectors can be purchased at the Western County Service Center, located at 705 North Zeeb Road in Ann Arbor. Take I-94 to Exit #169 and head North on Zeeb Road. We are on the West side of the road past McDonald's, next to Scio Township Hall. For questions, call (734) 222-3869.
Follow these recommendations when testing your home for radon:
Step 1: Take A Short-Term Test!
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Test the “lowest livable level” of your home, such as a finished basement (or an unfinished basement that could easily be finished or that you plan on finishing). If you do not have a basement, test on the main floor of the house. You don't need to test crawl spaces or “Michigan basements” unless people spend a lot of time down there!
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If your home has multiple foundations, test each area with a different foundation. For example, if the main part of your home is above a finished basement, and a family room is on a cement slab, a radon test should be conducted in the basement as well as in the family room.
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If your short-term test result is less than 4.0 pCi/L, your home has radon levels lower than the EPA’s recommended action level. Although exposures in this range do present some risk of lung cancer, reducing levels this low may be difficult, and sometimes impossible. Consider testing again in the winter to verify the results. Also, retest if you put an addition on your home, if you install a new heating or cooling system, or if you change your living patterns and begin occupying a lower level of your home (such as creating an exercise or play room in the basement).
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If your short-term test result is 4.0 pCi/L or higher, take a follow-up test to be sure. See Step 2.
Step 2: Follow Up On Your Test Results!
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If you need results quickly (generally if your first test was 10.0 pCi/L or higher), take a second short-term test. Test the same rooms using the same procedures. See Step 3.
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For a better understanding of your year-round radon level (generally if your first test was 4.0 - 9.9 pCi/L), take a long-term test. This time, test all livable levels of your home, such as the basement, first floor, and second floor. See Step 3.
Step 3: Fix Your Home If Necessary!
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If you followed up with a long-term test, fix your home if the result is 4.0 pCi/L or higher.
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If you followed up with a second short-term test, the higher your results, the more certain you can be that you should fix your home. Fix your home if the average of your first and second test is 4.0 pCi/L or higher.
Lowering RADON Levels (Mitigation)
If your home has only slightly elevated radon levels, activities such as sealing cracks in your basement or foundation may be able to lower the radon levels in your home. However, the best method of reducing radon levels involves installing a vent pipe through your home to vent the radon to the outside. This procedure is referred to as "subslab depressurization." Typically, a hole is drilled through the basement floor (or a sump pit is used), and a PVC pipe is placed in the hole and routed to the outside. A fan is then attached to the pipe to create suction to draw the radon into the pipe, rather than allowing it to creep into the home. A gauge is placed on the pipe to indicate that it is creating suction. A similar technique is used in homes with a crawl space. In addition to the vent pipe, a layer of plastic is placed on the floor of the crawl space and sealed around the edges to create a vapor barrier. The typical cost of a having a radon mitigation system installed in Washtenaw County is $800 - $1200.
Click here to view a video showing subslab depressurization techniques! (Must have Shockwave Software to view video. Video courtesy of the State of Pennsylvania Department of Environmental Protection.)
Typical radon mitigation using a sump pump pit:
If your home is found to have an elevated radon level, radon mitigation contractors can help you fix the problem. To find a radon mitigation service provider in your area, visit:
- National Environmental Health Association (NEHA) National Radon Proficiency Program
- National Radon Safety Board (NRSB) Radon Mitigators
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Angie Parsons, Environmental Educator, Washtenaw County Planning & Environment: (734) 222-3869
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Michigan Department of Environmental Quality's Indoor Radon Program: 1-800-RADON-GAS (1-800-723-6642)
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Radon Project at Columbia University - Researchers at Columbia University and Lawrence Berkeley National Laboratory have developed a clickable map of the United States to assist U.S. homeowners in deciding whether they may have serious radon problems and, if so, what to do.
page updated 1/18/08
on July 6, 2008 10:19 am