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Fact Sheet
January 2006
RADON FACT SHEET
What is Radon?
Radon is an odorless and invisible gas that is harmful to humans at elevated
levels. It occurs naturally in the soil, produced by the radioactive breakdown
of uranium and radium. Radon seeps into buildings, including homes. The
average indoor radon level in the United States is 1.3 picocuries per
liter (pCi/L) of air, based on a national residential radon survey completed
in 1991. Annual radon levels of more than 4 pCi/L are considered elevated,
and remediation is recommended.
Where is Radon Found?
The primary source of high levels of radon in homes is the surrounding
soil. Radon at elevated levels has been found in homes in every state.
It is found in new and old homes, with and without basements. The U.S.
Environmental Protection Agency (EPA) estimates that as many as one in
15 homes across the United States has elevated radon levels. Radon levels
can vary from area to area and can vary considerably from house to house,
even on the same street. EPA and the Surgeon General recommend radon testing
for all homes.
EPA has identified areas of the United States with the potential for elevated indoor radon levels. EPA's Map of Radon Zones assigns each of the 3,141 counties in the United States to one of three zones, based on radon potential:
- Zone 1 counties have a predicted average indoor radon screening level of more than 4 pCi/L (picocuries per liter)
- Zone 2 counties have a predicted average indoor radon screening level between 2 and 4 pCi/L
- Zone 3 counties have a predicted average indoor radon screening level of less than 2 pCi/L
Zone maps can be accessed on the Web at: http://www.epa.gov/radon/zonemap.html
How Does Radon Get Into A Home?
Warm air rises, creating a small vacuum in the lower areas of a house.
Radon gas seeps into a house the same way air and other soil gases enter:
from the soil around and under the home and through cracks in the foundation,
floor or walls; hollow-block walls; and openings around floor drains,
pipes and sump pumps.
What are the Health Effects of Radon?
There is overwhelming scientific agreement that exposure to elevated levels
of radon causes lung cancer in humans. Radiation emitted from radon can
cause cellular damage that can lead to cancer when it strikes living tissue
in the lungs. Radon is the second leading cause of lung cancer, responsible
for about 21,000 deaths every year in the US. The American Lung Association
HelpLine is an excellent source of clear and accurate information on lung
health issues. The HelpLine is unique in having professional, credentialed
staff qualified to help find answers to your questions. Call 1-800-LUNGUSA
for free counseling with registered nurses, respiratory therapists and
quit-smoking specialists. The line is open Monday through Friday from
7 a.m. to 7 p.m. CST. TTY for hearing impaired: (800) 501-1068.
How do Residents Find Out if Their Homes have Elevated Levels
of Radon?
Residents can test their homes for radon by obtaining test kits from their
state radon programs or the American Lung Association. Testing a home
for radon is simple and can help residents avoid putting themselves and
their families at risk. Radon test kits can be ordered from the Iowa Air
Coalition at 800-206-7818 or the American Lung Association at 800-586-4872.
How Can Residents Fix Elevated Levels of Radon?
Qualified radon mitigation contractors can install a radon mitigation
system that provides a permanent solution. A typical radon mitigation
system includes a suction point that addresses the soil under the structure.
A home that has been mitigated will usually have a much lower radon level
than the EPA’s action level of 4 picocuries per liter. Addressing
residential radon issues is an excellent first step toward assuring good
indoor air quality. A list of certified mitigation contractors can be
obtained from the state radon program by calling 800-383-5992 or by going
online to www.idph.state.ia.us/eh/radon.asp
and then click on the list of Iowa credentialed radon mitigation specialists.
A radon information packet can also be obtained by calling this number.
Where Can Residents Get Additional Information?
Additional information about radon is available from the state radon program
at 800-383-5992,
EPA’s Web site, www.epa.gov/radon
or the American Lung Association Web site at www.lungusa.org.
