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What is Radon?
Radon is a cancer-causing radioactive gas. You cannot see, smell or taste
radon, but it may be a problem in your home. It forms naturally from the
decay (breaking down) of radioactive elements, such as uranium, which are
found in different amounts in soil and rock throughout the world. Radon gas in
the soil and rock can move into the air and into underground water and
surface water. Air pressures within the home pull soil air (containing radon gas)
from below the foundation into living spaces. Because radon is a gas, it can
easily seep into your home through cracks in the foundation and directly
through masonry or other surfaces. The air pressure inside your home is
usually lower than pressure in the soil around your home’s
foundation. Because of this pressure difference, your house acts like a
vacuum, drawing soil air in.
Exposure:
For both adults and children, most exposure to radon comes from being
indoors in homes, offices, schools, and other buildings. Radon gas given off
by soil or rock can enter buildings through cracks in floors or walls;
construction joints; or gaps in foundations around pipes, wires, or pumps.
Radon levels are usually highest in the basement or crawl space. This level is
closest to the soil or rock that is the source of the radon. Therefore, people
who spend much of their time in basement rooms at home or at work have
a greater risk for being exposed. The primary routes of potential human
exposure to radon are inhalation and ingestion. Radon in the ground,
groundwater, or building materials enters working and living spaces and
disintegrates into its decay products.
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Does Radon Cause Cancer?
Being exposed to radon for a long period of time can lead to lung cancer.
Radon gas in the air breaks down into tiny radioactive elements (radon
progeny) that can lodge in the lining of the lungs, where they can give off
radiation. This radiation can damage lung cells and eventually lead to lung
cancer. There are no immediate symptoms that will alert you to the presence
of radon. It typically takes years of exposure before any problems surface.
Radon is estimated to cause many thousands of lung cancer deaths each year.
In fact, the Surgeon General has warned that radon is the second
leading
cause of lung cancer in the United States. Scientists estimate that about
20,000 lung cancer deaths per year are related to radon. Exposure to the
combination of radon gas and cigarette smoke creates a greater risk for lung
cancer than either factor alone. Most radon-related lung cancers develop in
smokers. However, radon is also thought to cause a significant number of lung
cancer deaths among non-smokers in the United States each year.
Some studies have suggested that radon exposure may be linked to other
types of cancer as well, such as childhood leukemia. Most U.S. EPA lifetime
safety standards for carcinogens are established based on a 1 in 100,000 risk
of death. Most scientists agree that the risk of death for radon at 4 pCi/l is
approximately 1 in 100. At the 4 pCi/l EPA action guideline level, radon carries
approximately 1000 times the risk of death as any other EPA carcinogen. It is
important to note that the action level is not a safe level, as there are no
"safe" levels of radon gas.
Can I avoid being exposed to radon?
Radon is in the air we breathe, both indoors and out, so it isn’t possible to
avoid it completely. But there may be things you can do to lower your
exposure.
Should you test for radon?
Testing is the only way to know your home's radon levels. Hire a professional
to test radon levels in your home.
The US EPA, Surgeon General, American Lung Association, American Medical
Association, and National Safety Council recommend testing your home for
radon because testing is the only way to know your home's radon levels.
Radon is a national environmental health problem. Elevated radon levels have
been discovered in every state. The US EPA estimates that as many as 8
million homes throughout the country have elevated levels of radon. Current
state surveys show that 1 home in 5 has elevated radon levels.
What to do if Radon levels are high:
You have tested your home for radon and confirmed that you have elevated
radon levels — 4 picocuries per liter (pCi/L) or higher. The EPA recommends
that you take action to reduce your home's radon levels if your radon test
result is 4 pCi/L or higher. High radon levels can be reduced through
mitigation.
A variety of methods can be used to reduce radon levels in your home, such
as sealing cracks in floors and walls or increasing ventilation through “sub-slab
depressurization” using pipes and fans. The EPA recommends that you have a
qualified contractor fix your home because lowering high radon levels requires
specific technical knowledge and special skills.
Without the proper equipment or technical knowledge, you could actually
increase your radon level or create other potential hazards and additional
costs.
Radon Mitigation:
Determine the appropriate radon mitigation method for your home (there are
many types of reduction methods depending on the levels or radon and the
layout of your home), hire a qualified contractor and maintain the radon
reduction system in your home.
A properly installed radon mitigation system lowers the amount of radon in
your home or building, making it as safe and radon free as practically possible.
This can be accomplished in several ways depending on the construction of the
home or office building. Generally a radon mitigation system is referring to an
"active" system or one with a radon fan. There are also "passive" radon
systems, those without radon fans, which usually rely on ventilation and sealing.
In a typical house prior to radon mitigation, the air pressure in the basement is
slightly lower than the air pressure under the basement floor. This pressure
differential influences sub-slab vapors to enter the house, through openings,
cracks and by diffusion. After mitigation, the pressure characteristics are
reversed. Soil vapor is diverted to the atmosphere. Sealing enhances the
performance of the vacuum system.
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