FAQ
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General Questions
What is radon?
Radon is a radioactive gas. It is colorless, odorless, tasteless, and chemically inert. Unless you test for it, there is no way of telling how much is present.
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. It can be found in all 50 states. 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. Radon has a half-life of about 3.8 days - half of a given quantity of it breaks down every 3.8 days. When radon undergoes radioactive 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 also be breathed. 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. 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. The EPA estimates that radon causes about 14,000 - 30,000 lung cancer deaths per year. It is widely agreed that radon exposure is most definitely the second leading cause of lung cancer.
What is the "acceptable" level of radon in air?
EPA states that any radon exposure carries some risk and recommends homes be fixed 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 often is indoor radon a problem?
Nearly one out of every 15 homes has a radon level EPA considers to be elevated - 4 pCi/L or greater. The U.S. average radon-in-air level in single-family homes is 1.3 pCi/L. Because most people spend as much as 90 percent of their time indoors, indoor exposure to radon is an important concern.
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. Air pressure inside homes 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 and other openings. Once inside, the radon can become trapped and concentrated. Openings which commonly allow easy flow of the gases include the following:
⦿ Cracks in floors and walls
⦿ Gaps in suspended floors
⦿ Openings around sump pumps and drains
⦿ Cavities in wallss
⦿ Joints in construction materials
⦿ Gaps around utility penetrations (pipes and wires)
⦿ Crawl spaces that open directly into the building
Radon may also be dissolved in water, particularly well water. The more radon there is in the water, the more it can contribute to the indoor radon level.
Trace amounts of uranium are sometimes incorporated into materials used in construction. These include, but are not limited to concrete, brick, granite, and drywall. Though these materials have the potential to produce radon, they are rarely the main cause of an elevated radon level in a building. The average indoor level of radon is 1.3 pCi/L and the average outdoor level of radon is 0.4 pCi/L.. While radon problems may be more common in some geographic areas, any home may have an elevated radon level. The state of Illinois tends to have higher levels of radon. 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 the lowest occupied space. Real estate transactions require testing in the lowest livable space. Radon has been found in homes all over the United States and knows no boundaries. 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 have a licensed professional test for it.
If a test result is less than 4 pCi/L what should be done next?
If the result of an initial test measurement is below 4 pCi/L, a follow-up test is not necessary. Because radon levels can 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 levels to change.
If a test result is 4 pCi/L or higher, what should be done next?
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 test results are less than 4 pCi/L, consider testing again sometime in the future. Additionally, because radon levels can fluctuate between seasons or during varying weather conditions by a considerable amount, a retest following the initial test may be warranted.
What can be done to reduce radon in a home?
Your house type will affect the kind of radon reduction system that will work best. Houses are generally categorized according to their foundation design. For example: basement, slab-on-grade (concrete poured at ground level), or crawlspace (a shallow unfinished space under the first floor). Some houses have more than one foundation design feature. For instance, it is common to have a basement under part of the house and to have a slab-on-grade or crawlspace under the rest of the house. In these situations a combination of radon reduction techniques may be needed to reduce radon levels to below 4 pCi/L.
The method that we at Radon Rescue use to lower radon levels in your home actually prevents radon from entering your home and the EPA generally recommends that method. Such systems are called "sub-slab depressurization," and do not require major changes to your home. These systems change the pressure dynamics of your home by circumventing the mechanics that bring radon into your home. Similar systems can also be installed in houses with crawl spaces. The right system depends on the design of your home and other factors.
Supplying us with any information that you may have about the construction of your home would most certainly help us determine the best system for you