You can't see it, smell it or taste it, however radon is a very real,
radioactive gas that occurs naturally in the environment, particularly in some
geographic regions. Formed by the disintegration of radium (a decay product of
uranium), the gas can move freely through the soil enabling it to escape to the
atmosphere or seep into buildings. People can be exposed to radon in homes,
workplaces, schools, and other places.
In open air, radon gets diluted to very low concentrations and poses a
negligible threat. When released into a building through cracks in the walls
and floors, or through gaps around pipes and cables, however, it can accumulate
to high levels. Basements and crawl spaces tend to have the highest
concentrations of radon because these areas are closest to the source and tend
to be poorly ventilated. Therefore, people who spend much of their time in
basement rooms at home or at work could have a greater risk for exposure.
In high enough concentrations or with prolonged exposure, radon can cause lung
cancer. It is the second-leading cause of lung cancer after smoking. According
to the US-American Environmental Protection Agency (EPA) radon claims about
20,000 lives in the U.S. each year. The Canadian Medical Association Journal
says radon is estimated to cause about 10% of lung cancers, or more than 2,000
cases each year in Canada.
Radon emits alpha particles and produces several solid radioactive products
called radon daughters. Most radon daughters become attached to tiny dust
particles in indoor air. Some don't. A fraction of both attached and unattached
radon daughters are deposited into the lungs, where they emit particles that
are absorbed in the nearby lung tissues. Since alpha particles cannot penetrate
more than a fraction of a millimeter into the tissue, the damage is confined to
the lung tissue in the immediate area.
The degree of risk from radon depends on how much radon is present, how long
the person is exposed, and whether or not the person smokes or is exposed to
second-hand smoke. Since smoking is the number one cause of lung cancer and
radon is the second, the combination of inhaling radon gas and exposure to
smoke significantly increases the risk. To further compound the problem, there
are no warning signs of radon exposure.
Scientifically, there has been no direct evidence linking indoor radon exposure
in buildings to an increased risk of lung cancer; the link is based mainly on
data from a study of lung cancer mortality among uranium miners and other
workers exposed to very high levels of radon daughters. Regardless, the EPA
recommends radon testing in the home or workplace. It's the only sure way of
knowing how much of this imperceptible gas is present in your home or workplace.
Radon Detection and Control
You can't detect the presence of radon with any of your senses, but you can
test a home or workplace fairly easily for the presence of radon, either with a
do-it-yourself-kit or by hiring professionals to perform long term testing.
Health Canada offers a Guide for Radon Measurements in Public Buildings.
Once radon has been detected, exposure must be controlled.
Air filtration can decrease the radon daughter concentration as much as 90
percent by removing the airborne particles that the radon daughters are
Increasing ventilation reduces indoor radon levels. Opening a window can help
lower the radon level by allowing the inside air to escape and letting fresh
Caulking and sealing cracks and holes in basement floors and walls help stop
the release of radon from the ground into the building. Painting basement
floors and wall surfaces with epoxy paints also helps reduce radon emission.
Where radon levels are high because uranium mill tailing was used as landfill,
it may be necessary to replace the fill, or reduce the radon concentration by
coating the surface of the building foundation.
Invisible but detectable, radon exposure is a health hazard that can be
prevented. A simple test could ease your mind and preserve your health. Start
your new year off on the right track by putting radon on your radar.
AplusA-online.de - Source: Canadian Centre for Occupational Health and Safety