Should I be concerned about Radon Gas in My Basement?
Definition of Radon Gas
Radon is a naturally occurring, inert, radioactive gas, derived from naturally occurring uranium deposits in the earth. It is colorless, odorless, and tasteless. Radon-222 is the environmentally important form of radon. Radon itself is not particularly harmful, but some of its alpha-emitting polonium radioactive decay products may heavily irradiate bronchial epithelial cells for many months or years. Therefore, radon is believed to be a risk factor for lung cancer.
Radon-222 enters the indoor environment from the soil by penetration of a building’s foundation or by release from well water. The equilibrium levels that are achieved depend on rates of replenishment, radioactive decay and ventilation.
Although the average indoor domestic radon level in North America is small, great variations exist. Some houses have radon levels higher than the control levels in underground mines. Many of these homes are in areas known to have high background levels of natural radiation. However, not all of the homes in such regions are affected, and not all of the affected homes are located in those regions.
Cumulative domestic exposure levels, therefore, can be quite variable, depending on the amount of time spent in the home and the percentage of that time spent in the high-radon areas of the home. Outdoors, the concentrations of radon gas are trivial.
The Risk of Living with Radon
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 may be many years.
Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, we know more about radon risks than risks from most other cancer-causing substances. This is because estimates of radon risks are based on studies of cancer in humans (underground miners).
Smoking combined with radon is an especially serious health risk. Stop smoking and lower your radon level to reduce your lung cancer risk.
How Does Radon Get Into Your Home
Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water. Materials can give off radon, too. However, building materials rarely cause radon problems by themselves.
Radon Gets in Through:
Cracks in solid floors
Cracks in walls
Gaps in suspended floors
Gaps around service pipes
Cavities inside walls
The water supply
Diagnosis of Radon Gas
Like all sources of ionizing radiation, radon gas is odorless and thus not easily detected.
The detection device is placed in the lowest livable level of the house (normally not the basement), left there for the prescribed length of time, and then sent to the manufacturer, who sends you a report.
Because radon levels vary from place to place in the house and from time to time during the year, it is recommended you buy at least two detectors, place them in the living room and bedroom, and take two readings – one in midsummer and one in midwinter. The average of the total readings is then a good estimate of year-round.
Prevention of Radon Gas
The most cost-effective way to reduce the incidence of radon-induced lung cancer appears to be to reduce the number of smokers (there appears to be some synergism between smoking and radon exposure).
Additional measures that might be considered include improving the ventilation systems in existing homes (particularly in parts of the country where risk has been identified) and modifying the requirements for the ventilation systems for new constructions.
Educating the population to do simple things, such as avoiding the use of basements as major living areas and discouraging the improper handling of actinide-containing mineral collections displayed in living areas, are further examples of potentially cost-effective intervention.
Radon can be found all over North America
Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon can be found all over North America. It can get into any type of building – homes, offices, and schools – and result in a high indoor radon level. But you and your family are most likely to get your greatest exposure at home, where you spend most of your time.
How to Lower the Radon Level in Your Home
Radon reduction systems work and they are not too costly. Some radon reduction systems can reduce radon levels in your home by up to 99%. Even very high levels can be reduced to acceptable levels.
Since there is no known safe level of radon, there can always be some risk, but lowering the radon level in your home can reduce the risk.
There are several proven methods to reduce radon in your home, but the one primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside. This system, known as a soil suction radon reduction system, does not require major changes to your home. Sealing foundation cracks and other openings makes this kind of system more effective and cost-efficient.
Similar systems can also be installed in houses with crawl spaces. Radon contractors can use other methods that may also work in your home. The right system depends on the design of your home and other factors.
How to Test Your Home
You can’t see radon, but it’s not hard to find out if you have a radon problem in your home. All you need to do is test for radon. Testing is easy and should only take a few minutes of your time.
The amount of radon in the air is measured in “picoCuries per liter of air,” or “pCi/L.” Sometimes test results are expressed in Working Levels (WL) rather than picoCuries per liter (pCi/L) (4 pCi/L equals to 0.016 WL). There are many kinds of low-cost “do-it-yourself” radon test kits you can get through the mail and in hardware stores and other retail outlets. If you prefer, or if you are buying or selling a home, you can hire a qualified tester to do the testing for you. You should first contact your state/provincial radon office about obtaining a list of qualified testers. You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area.
There are Two General Ways to Test for Radon:
The quickest way to test is with short-term tests. Short-term tests remain in your home for two days to 90 days, depending on the device. “Charcoal canisters,” “alpha track,” “electret ion chamber,” “continuous monitors,” and “charcoal liquid scintillation” detectors are most commonly used for short-term testing. Because radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. If you need results quickly, however, a short-term test followed by a second short-term test may be used to decide whether to fix your home.
Long-term tests remain in your home for more than 90 days. “Alpha track” and “electret” detectors are commonly used for this type of testing. A long-term test will give you a reading that is more likely to tell you your home’s year-round average radon level than a short-term test.
Step 1. Take a short-term test. If your result is 4 pCi/L or higher take a follow-up test(Step 2) to be sure.
Step 2. Follow up with either a long-term test or a second short-term test:
For a better understanding of your year-round average radon level, take a long-term test.
If you need results quickly, take a second short-term test.
The higher your initial short-term test result, the more certain you can be that you should take a short-term rather than a long-term follow up test. If your first short-term test result is more than twice EPA’s 4 pCi/L action level, you should take a second short-term test immediately.
If you followed up with a long-term test: Fix your home if your long-term test result is 4 pCi/L or more. If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home. Consider fixing your home if the average of your first and second test is 4 pCi/L or higher.
What Your Test Results Mean
The average indoor radon level is estimated to be about 1.3 pCi/L, and about 0.4 pCi/L of radon is normally found in the outside air. The U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels. While this goal is not yet technologically achievable in all cases, most homes today can be reduced to 2 pCi/L or below.
Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results are close to 4 pCi/L. For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that your year-round average is somewhat below 4 pCi/L. However, EPA believes that any radon exposure carries some risk – no level of radon is safe. Even radon levels below 4 pCi/L pose some risk, and you can reduce your risk of lung cancer by lowering your radon level.
If your living patterns change and you begin occupying a lower level of your home (such as a basement) you should retest your home on that level.
Even if your test result is below 4 pCi/L, you may want to test again sometime in the future.
Radon in Water
There are two main sources for the radon in your home’s indoor air, the soil and the water supply. Compared to radon entering the home through water, radon entering your home through the soil is usually a much larger risk.
The radon in your water supply poses an inhalation risk and an ingestion risk. Research has shown that your risk of lung cancer from breathing radon in air is much larger than your risk of stomach cancer from swallowing water with radon in it. Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.
Radon in your home’s water is not usually a problem when its source is surface water. A radon in water problem is more likely when its source is ground water, e.g. a private well or a public water supply system that uses ground water. If you are concerned that radon may be entering your home through the water and your water comes from a public water supply, contact your water supplier.
If you’ve tested your private well and have a radon in water problem, it can be fixed. Your home’s water supply can be treated in two ways. Point-of-entry treatment can effectively remove radon from the water before it enters your home. Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use and are not effective in reducing the risk from breathing radon released into the air from all water used in the home.
New homes can be built with radon-resistant features.
Radon-resistant construction techniques can be effective in preventing radon entry. When installed properly and completely, these simple and inexpensive techniques can help reduce indoor radon levels in homes. In addition, installing them at the time of construction makes it easier and less expensive to reduce radon levels further if these passive techniques don’t reduce radon levels to below 4 pCi/L. Every new home should be tested after occupancy, even if it was built radon-resistant. If radon levels are still in excess of 4 pCi/L, the passive system should be activated by having a qualified mitigator install a vent fan.
Radon and Home Renovations
If you are planning any major structural renovation, such as converting an unfinished basement area into living space, it is especially important to test the area for radon before you begin the renovation. If your test results indicate a radon problem, radon-resistant techniques can be inexpensively included as part of the renovation. Because major renovations can change the level of radon in any home, always test again after work is completed.
Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems. A qualified contractor can study the radon problem in your home and help you pick the right treatment method.
Check with your state or provincial office for names of qualified or state certified radon contractors in your area. You can also contact private radon proficiency programs for lists of privately certified radon professionals in your area. Choosing someone to fix your radon problem is much like choosing a contractor for other home repairs – you may want to get references and more than one estimate.
You should also test your home again after it is fixed to be sure that radon levels have been reduced. Most soil suction radon reduction systems include a monitor that will indicate whether the system is operating properly. In addition, it’s a good idea to retest your home every two years to be sure radon levels remain low.
This paper is intended for informational purposes only. Nothing contained herein constitutes legal, financial or other professional advice. Transmission of these materials is not intended to create, and receipt does not constitute, any relationship of any kind between the provider and the recipient. Some of these points may not apply in your area. Different term and conditions may vary from state to state and province to province. All articles, text and photographic material presented here is for the use and pleasure of the recipient only. Download PDF