Introduction to Radon

Radon is colorless, tasteless, and odorless. There’s no way of knowing where it is without a test. But it is present in many homes and it is a health hazard to be reckoned with.

What Is Radon?

Radon is a radioactive gas which is chemically inert, and is produced by the naturally occuring radioactive decay of uranium. Uranium is sometimes present in soil, rock, and water. The way radon is formed is as follows. Uranium breaks down, forming other products, like radium, which in turn breaks down and forms radon. Although it is chemically inert, radon changes, because it, too, undergoes the radioactive decay cycle.

Radon has a radioactive half-life of around four days. This means that every four days or so, half of the present radon will undergo radioactive decay, dividing into two separate parts. One part is referred to as radiation, and the second, a "daughter." The daughters continue dividing, stopping only when a stable daughter, which is nonradioactive, is formed. Byproducts of the decay process of the radon include alpha, beta, and gamma radiation. Each of these types of particles travels differently. Alpha particles cannot be absorbed through the skin, but beta particles may travel only partway into the human body. It is possible for gamma radiation to be absorbed through the human body.

Where Is Radon?

Radon exists naturally in the Earth’s crust, where low levels of uranium are found. The presence of radon has been found in the air throughout the world, which is why the World Health Organization (WHO) has launched a campaign to increase awareness of the danger of radon. As radon follows its natural path from the ground to the air above, it can move into houses, office buildings and schools.

Radon can enter buildings through:

• Cavities in walls
• Construction joints
• Cracks in the foundation, walls, and solid floors
• Crawl spaces that open into the building
• Gaps or cracks in suspended floors and around utility pipes
• Openings around drains and sump pumps
• The building's water supply

Health and Radon

The “progeny” of radon are no longer in a gaseous state. This means they can be attached to particles such as dust, which can be transported by the air and breathed into the body. These particles can then become trapped in the lungs, where they continue to break down. This can lead to lung tissue damage, which leads to pulmonary fibrosis and emphysema, as well as lung cancer, which sometimes does not manifest until long after exposure. The Surgeon General has cautioned that radon is the number two cause of cancers of the lung (smoking being the first) in the US.

Radon Testing

Although there is no direct testing for radon in the tissue of humans, its products of decay have been identified in the body through the testing of lung and bone tissues and urine. These tests do not clarify the exposure nor predict the health effects.

Building testing, on the other hand, is simple, inexpensive, straightforward, and should be done, because nearly one of every 15 homes in the United States is estimated to have radon levels that are higher than recommended. Because there is no way to predict the radon amounts in your home based on regional and neighboring building information, even if others who live near you have low levels, you should test your home.

There are two types of tests: short-term and long-term. Short-term testing takes place for between two and 90 days; long-term testing exceeds 90 days. For more information about radon and testing, for either a do it yourself test, or to find a qualified person to test or fix your home, visit the Environmental Protection Agency(EPA) web site.

For those who have more general questions, visit the the EPA's State and Regional Indoor Environments site.

Preventing Radon from Entering New Homes

New construction techniques have been designed to keep radon out of homes from the start. This is simpler and less expensive than mitigating radon should it be found later. While not always completely effective, these approaches are still valid and useful.