Radon is
a colorless, odorless,
tasteless, and chemically
inert radioactive gas. It is
formed by the natural
radioactive decay of uranium
in rock, soil, and water.
Naturally existing, low
levels of uranium occur
widely in earth's crust. It
can be found in all 50
states. Unless you test for
it, there is no way of
telling how much is present.
When
radon undergoes radioactive
decay, it emits ionizing
radiation in the form of
alpha particles.
It also produces
short-lived decay products,
often called progeny or
daughters, some of which are
also radioactive.
Unlike radon, the
progeny are not gases and
can easily attach to dust
and other particles. Those
particles can be transported
by air and can also be
breathed. The decay of progeny
continues until stable,
non-radioactive progeny are
formed. At each step in the
decay process, radiation is
released.
Sometimes,
the term radon is used in a
broad sense, referring to
radon and its radioactive
progeny all at once. When
testing measures radiation
from the progeny, rather
than radon itself, the
measurements are usually
expressed in working level
(WL) units. When radiation
from radon is measured
directly, the amount is
usually expressed in
picocuries per liter of air
(pCi/L). Nearly one out of
every 15 homes has a radon
level EPA considers to be
elevated—4 pCi/L or
greater. The U.S. average
radon-in-air level in single
family homes is 1.3 pCi/L.
Radon is the second
leading cause of lung cancer
in the United States. Breathing radon does
not cause any short-term
health effects such as
shortness of breath,
coughing, headaches, or
fever. Research suggests
that swallowing water with
high radon levels may pose
risks, too, although risks
from drinking water
containing radon are much
lower than those from
breathing air containing
radon.
Radon enters the
building through cracks in
the foundation, floors and
walls, cavities within
walls, joints in
construction materials,
crawl spaces, gaps in
suspension floors, and gaps
around utility penetrations.
Trace amounts of
uranium are sometimes
incorporated into materials
used in construction. These
include, but are not limited
to concrete, brick, granite,
and drywall. Though these
materials have the potential
to produce radon, they are
rarely the main cause of an
elevated radon level in a
building.
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. Although high
concentrations of radon in
groundwater may contribute
to radon exposure through
ingestion, the inhalation of
radon released from water is
usually more important.
Ground water has a
higher concentration than
surface waters.
The health hazard from
radon does not come
primarily from radon itself,
but rather from the
radioactive products formed
in the decay of radon. The
general effects of radon to
the human body are caused by
its radioactivity and
consequent risk of
radiation-induced cancer. Lung
cancer is the primary
observed consequence of high
concentration radon
exposures; both human and
animal studies indicate that
the lung and respiratory
system are the primary
targets of radon
daughter-induced toxicity.
More studies are
needed to determine the
causative relationship to
other cancers.
Testing is easily done
over a short period of days.
Weather can affect
the results.
Multiple tests may be
required.
Radon Gas Detection
|
Radon Control
|
Radon Detection
Specialist
|
Radon Information EPA
|
Radon Detection and
Control
|
Radon Information CA