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More is known about the health risk of radon
exposure than almost any other human carcinogen. Because it's
odorless and invisible and the lung cancer usually shows up over a long period
of exposure, the danger of radon is often underestimated. Lung cancer is the most common form of cancer in America
and in fact, kills more people than colon, prostate and breast cancer
combined. Approximately 50% of the people diagnosed with lung
cancer have never smoked or are former smokers.
The US EPA has Updated its Assessment of Risks from Radon in Homes click
above
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Where Does Radon Come From? Radon is a
naturally occurring odorless, tasteless, colorless radioactive gas. It is
produced by the natural breakdown of radium in soil, rock and water. Many
homes and other buildings, such as schools and offices have high levels of
radon. Because it's odorless and invisible and the lung cancer usually shows
up over a long period of exposure, the danger of radon is often
underestimated. Because of
the stack effect, radon can be drawn into the home from the soil below.
Common entry points are cracks in concrete floors, utility access points,
spaces around floor drains, sump pits, construction joints and tiny cracks in
basement walls. The concentration will depend on the source strength and the
rate of pressure driven entry. How Does Radon Induce Lung Cancer? If inhaled,
airborne radon decay products become deeply lodged or trapped in the lungs, where
the alphas radiate and penetrate the cells of the mucous membranes, bronchi,
and other pulmonary tissues. The ionizing
radiation energy affecting the bronchial epithelial cells is believed to
initiate the process of the carcinogenesis.
Although, radon-related lung cancers are mainly seen in the upper
airways, radon increases the incidence of all histological types of lung
cancer, including small cell carcinoma, adenocarcinoma, and squamous cell
carcinoma. What is The Evidence? More is known about the health
risk of radon exposure than almost any other human carcinogen. In fact, the University of Iowa College of
Public Health recently compiled a bibliography of radon epidemiology research
that took 192 pages just to list! These include
extensive studies of thousands of underground miners, carried out over more
than 50 years worldwide, that have consistently shown an increase in lung
cancer occurrence with exposure to radon progeny. Miner studies have produced some interesting findings.
For example, at equal cumulative exposures, low exposures in the range of
EPA’s 4 pCi/L Action Level over longer periods produced greater lung cancer
risk that high exposures over short periods. Non-smoking miners were observed
to have a significant increased risk, even after controlling for, or in the
absence of other mine exposures such as asbestos, silica, diesel fumes,
arsenic, chromium, nickel, and ore dust. An added synergic effect between
radon exposure and cigarette smoking was also found. The NAS has
repeatedly concluded that it is reasonable to extrapolate from the miner data
to a residential situation and in doing so, consider that the effective doses
per unit of exposure for people in homes is approximately 30% less than for
the miners.
Residential studies have yielded similar findings. The Iowa Residential Radon Study completed
in May of 2000 determined that even at the EPA Action Level of 4 pCi/L, an
approximate 50 percent excess lung cancer risk was found among the women in
the study after correcting for the impact of smoking. A 2002 residential study conducted in
northeast Spain yielded similar results. Even at concentrations far below
official guideline levels, the Spanish study found that radon might lead to a
2.5-fold rise in the risk of lung cancer. Exposures of animals
further confirm that radon and its progeny cause lung cancer. Health effects
observed in animals exposed to radon include lung carcinomas, pulmonary
fibrosis, emphysema, and a shortening of life span. The incidence of respiratory tract tumors increased with an
increase in cumulative exposure.
Exposure to ore dust and diesel fumes simultaneously with radon did
not increase the incidence of lung tumors above that produced by radon
progeny exposures alone. In a study of rats exposed to radon progeny, it was
observed that the risk of lung cancer was elevated at exposure levels similar
to those found in homes. Can High Radon Levels Be Reduced? A certified or licensed contractor can easily and affordably
reduce elevated radon levels. Most techniques prevent radon from entering
your home by drawing the radon from below the house and venting it through a
pipe to the air above the house where it quickly dilutes. Mitigation can also decrease moisture and other soil gases
entering the home, reducing mold, mildew, methane, pesticide gases and other
air quality problems. Facts About Lung CancerØ
Lung cancer
is the leading cause of cancer deaths in the United States. Ø
Lung cancer kills more Americans each
year than breast, prostate and colorectal cancers combined. Ø
Lung cancer kills more women each
year than breast cancer. Ø
Lung cancer kills 85% of
newly diagnosed patients within five years. Ø
Approximately
50% of the people diagnosed with lung cancer have never smoked or are former
smokers. Ø
Lung
cancer gets few of the research dollars because of the perception it is
self-inflicted by smoking. Ø
In 2003, approximately $1,740 was spent on
research per lung cancer death, compared with: $13,649 per breast cancer
death, $10,560 per prostate cancer death and $4,581 per colorectal cancer
death. LC Stats courtesy of
the LUNGevity Foundation |
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