 Radon*
What is Radon?
Radon is a natural radioactive gas that emanates from the ground
into the air. It’s chemically inert, and has no odor, color
or taste. It is produced from radium in the decay chain of uranium,
an element found in varying amounts in all rocks and soil.
When radon gas escapes from the ground into the air it emits heavily
ionizing radiation called alpha particles. These particles are electrically
charged and attach to aerosols, dust and other particles in the
air we breathe. As a result, radon progeny may be deposited on the
cells lining the airways where the alpha particles can damage the
DNA and potentially cause lung cancer.
Radon gas in the air is present
worldwide, its concentration depending on the highly variable uranium
content of the soil. It is the second most important risk factor
for lung cancer, causing between 6 and 15% of all cases, yet, there
is little public awareness of radon as a serious threat to human
health.
"Radon poses an easily reducible health risk to populations
all over the world, but has not up to now received widespread attention,"
said Dr Mike Repacholi, coordinator of the World Health Organization's
Radiation and Environmental Health Unit. "Radon is all around
us. Radon in our homes is the main source of exposure to ionizing
radiation, and accounts for 50% of the public's exposure to naturally-occurring
sources of radiation in many countries."
Exposure and Lung Cancer
Although the average exposure to radon varies enormously, recent
studies have shown that, when exposed to a radon concentration of
100 Bq (Becquerels)/m3, a non-smoker's risk of lung cancer by age
75 years increases by 1 in a 1000 compared to non-exposed people.
Among those who smoke and are exposed to the same radon concentration,
the risk of lung cancer is about 25 times greater. On a global level,
tens of thousands of lung cancer deaths annually can be attributed
to radon. Most of the radon-induced lung cancer cases occur among
smokers.
Radon and Your Home
Due to dilution in the air, outdoor radon levels are usually very
low. Radon levels indoors are higher and pose the greatest exposure
risk for the average person. The concentration of radon in a home
depends on the amount of uranium producing the radon in the underlying
rocks and soils, as well as the routes available for its passage
into the home and the rate of exchange between indoor and outdoor
air.
Radon gas enters houses through openings such as cracks at concrete
floor-wall junctions, gaps in the floor, small pores in hollow-block
walls, and also sumps and drains. Consequently, radon levels are
usually higher in basements, cellars or other structural areas in
contact with soil, and the radon concentrations in houses directly
adjacent to each other can be very different.
Radon exposure in homes can be easily mitigated during the construction
of new homes, but existing buildings can also be protected from
radon. Most measures such as increasing under-floor ventilation
and sealing cracks and gaps in the floor require simple alterations
to the building, but other approaches may have to be taken in areas
with high radon concentrations. Overall, reducing radon exposure
is an important contribution to the goal of good quality indoor
air.
Testing
Testing kits can be bought through many hardware stores or if you
prefer, you can hire a professional tester. In the U.S., your state
should have a radon office that can give you a list of qualified
testers.
* This story has been adapted from a news release issued the
World Health Organization, , June 21st, 2005
Note the information provided is for educational purposes only.
See you doctor for advice on your specific medical conditional.
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