Q.What is radon?

A. 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 Earth's crust. It can be found in all 50 states. Like uranium, radon decays, too. If it does this in your lungs, the alpha particles it releases can harm the DNA in your cells.

Q.What health effects are associated with radon exposure?

  • Radon can cause a number of health effects such as the following:
  • Persistent coughing
  • Shortness of breath
  • Chest pain
  • Frequent infections such as bronchitis or pneumonia
  • Long exposures to radon can sometimes lead to lung cancer

Q.Why is the 4 pCi/L the recommended action level for Radon?

A. EPA recommended this mitigation action level in 1986 for several reasons. First, at lower levels (2 pCi/L) measurement devices’ false negative errors increase threefold, and false positive errors increase twofold. Secondly, mitigation research indicates that elevated levels can be reduced to 4 pCi/L or less 95% of the time. Research shows that 2 pCi/L can be achieved 70% of the time. Further, today’s mitigation technology can reduce radon levels to between 2 and 4 pCi/L most of the time. Finally, cost benefit analysis performed in 1986 indicate that an action level of 4 pCi/L results in a cost of about $700,000 per lung cancer death saved. If the action level was set at 3 pCi/L, the cost would be $1.7 million, and if set at 2 pCi/L, the cost would be $2.4 million per lung cancer death saved. EPA states that 4 pCi/L is a recommended action level, yet homeowners can further reduce their potential lung cancer risk by mitigating homes that are below 4 pCi/L.

Q.What is "picocurie" (pCi)?

A. 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, the EPA's recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period.

Q.What is "working level" (WL)?

A. Some devices measure radiation from radon decay products, rather than radiation coming directly from radon. Measurements from these devices are often expressed as WL. As noted above, conversions from WL to pCi/L are usually approximate. A level of 0.02 WL is usually equal to about 4 pCi/L in a typical home.

Q.How often is indoor radon a problem?

A. Based on a national residential radon survey completed in 1991, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in air in the United States. The average outdoor level is about 0.4 pCi/L.”

Q.How does radon get into a home or building?

A. Radon is a gas that can seep from the ground upwards into the air in a home. Radon typically enters through the foundation of the house through way of crawl spaces and basements. Radon can also enter the home through:

  • Cracks in basement floors
  • Drains
  • Exposed soil
  • Sump pump pits or perimeter drains

Q.Why should I test my home for radon?

A. As the EPA states, “Any radon exposure has some risk of causing lung cancer. The lower the radon level in your home, the lower your family’s risk of lung cancer. Based on a national residential radon survey completed in 1991, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in air in the United States. The average outdoor level is about 0.4 pCi/L.”

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