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I realize most people find it difficult
to understand radon; a colorless, odorless, inert radioactive gas. You
cannot see it, smell it, or feel it; yet we cannot completely avoid
breathing radon. There is about 0.35 pCi/L of radon in the outside air we
breathe. Understanding the risks associated with radiation exposure is even
more perplexing. I hope reading this information will enable you to make an
informed decision about the radon levels measured in your house.
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TABLE OF CONTENTS
Section
| 1...Where Does Radon Come From? |
| 2...How Does Radon Get Into The
House? |
| 3...What About Radon in Well
Water? |
| 4...What About Radon in City
Water? |
| 5...What Is the Risk of Radon
Exposure? |
| 6...How Serious a Risk is Radon? |
| 7...Do Scientists Agree that
Radon is Dangerous to Breathe? |
| 8...Who Do I Believe? |
| 9...What Should I Do About The
Levels of Radon in My Home? |
| 10...What Should I Look at in
Deciding Whether to Mitigate or Not? |
| 11...What if, I Decide to
Reduce the Radon Levels in My Home? |
| 12...What Should I Look for in
a Properly Installed System? |
| 13...Who Should Pay to Get the
Radon Reduced? |
| 14...How Much Does it Cost to
Operate These Systems? |
| 15...How Can I Learn More About
Radon? |
1. WHERE DOES RADON COME FROM?
| Radon comes from the natural radioactive decay of
radium and uranium found in the soil beneath the house. The amount of
radon in the soil depends on complex soil chemistry, that varies from one
house to the next. Radon levels in the soil range from a few hundred to
several thousands of pCi/L. The amount of radon that escapes from the soil
to enter the house depends on the weather, soil porosity, soil moisture,
and the suction within the house. |
2. HOW DOES RADON GET INTO THE HOUSE?
| Houses act like large chimneys. As the air in the
house warms, it rises to leak out the attic openings and around the upper
floor windows. This creates a small suction at the lowest level of the
house, pulling the radon out of the soil and into the house. You can test
this on a cold day by opening a top floor window an inch. You will notice
warm air from the house rushing out that opening; yet, if you open a
basement window an inch, you will feel the cold outside air rushing in.
This suction is what pulls the radon out of the soil and into the house.
You might think caulking the cracks and the openings in the basement floor
will stop the radon from entering the house. However, scientific studies
show, it only takes enough unsealed cracks or pin holes in the caulking to
equal a hole 1/2" in diameter to let all the radon in. It is unlikely that
caulking the accessible cracks and joints will permanently seal the
openings radon needs to enter the house. The radon levels will still
likely remain unchanged. |
| Fortunately, there are other extremely effective
means of keeping radon out of your home. Throughout the country, several
million people have already tested for radon. Some houses tested as high
as 2,000-3,000 pCi/L; yet, there hasn't been one house that could not
mitigate to an acceptable level. Mitigation usually costs between
$500-$1500. |
3. WHAT ABOUT RADON IN WELL WATER?
| Underground well water can transport the radon from
the soil into the house, when taking a shower, doing laundry, or washing
dishes. The EPA says it takes about 10,000 pCi/L of radon in water to
contribute 1.0 pCi/L of radon in air throughout the house. The ratio of
radon in water to radon in bathroom air while showering can be much
higher, typically from 100 to 1; to about 300 to 1. The average Colorado
well tests about 3,000 pCi/L with one well testing more than 3,000,000 pCi/L.
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4. WHAT ABOUT RADON IN CITY WATER?
| If your water comes from a municipal reservoir
supply, you need not worry about radon in the water. When radon in water
is stored in a reservoir for more than 30 days, the radon decays away to
practically nothing. Every 3.825 days half the radon disappears through
natural radioactive decay. |
5. WHAT IS THE RISK OF RADON EXPOSURE?
| Scientists believe radon exposure is the second
leading cause of lung cancer. When radon decays, it shoots off alpha
particles. These are small, heavy, electrically charged, sub-atomic
particles consisting of two protons and two neutrons. If an alpha particle
strikes the chromosomes in a lung cell, it could alter the way that cell
reproduces. Our bodies immune system should recognize and destroy these
mutant cells before they can multiply over the next 10 to 20 years into a
recognizable cancerous growth. |
| Some peoples immune system is better than others.
Because of these inherent differences, radon doesn't affect everyone the
same. |
6. HOW SERIOUS A RISK IS RADON?
| According to the following EPA radon risk chart,
radon is a serious health problem. |
If 1,000 people were exposed to this level over a life
time who are:
Annual
Radon Level....Smokers.............Never Smokers
20 pCi/L....14% or135 people.....0.8% or 8 people could get lung cancer
10 pCi/L.....7% or 71 people.....0.4% or 4 people could get lung cancer
4 pCi/L......3% or 29 people.....0.2% or 2 people could get lung cancer
2 pCi/L......2% or 15 people.....0.1% or 1 person could get lung cancer
7. DO SCIENTISTS AGREE THAT RADON IS DANGEROUS TO
BREATHE?
| There is little disagreement that breathing the
hundreds of pCi/L of radon that caused thousands of uranium miners to get
fatal lung cancer is definitely harmful. Many scientists disagree with the
EPA about what the level of radon should be before it should be reduced.
|
| The EPA studied the lung cancer risk of uranium
miners exposed to 400 pCi/L. They assume the risk of a home owner exposed
to 4 pCi/L to be one hundredth as much. Based on this assumption, the EPA
guideline level of 4 pCi/L represents a much greater risk than allowed for
other environmental pollutants. |
| Other scientists have tested more than 70,000 homes
across the United States. This study shows the counties with the highest
average radon levels had the lowest incidence of cancer. Perhaps,
breathing the low levels of radon found in the home environment, might not
be harmful. Neither study fully accounts for all the different confounding
factors that can cause cancer. The truth probably lies somewhere between
these two theories. |
8. WHO DO I BELIEVE?
| In 1988 the United States Congress passed
legislation, directing the EPA to work toward a long term national goal,
"The air within buildings in the United States should be as free of radon
as the ambient air outside of buildings." Real estate agents are hired and
paid by the sellers, to represent the sellers economic intrests, in the
sale of their house. Understandably, you might get two completely
different opinions about radon, depending whether you ask the EPA, or your
real estate agent. Because you have hired us to test for radon, and
explain the test results. We will offer our opinion on the subject, and
guidance on a prudent course of action. |
9. WHAT SHOULD I DO ABOUT THE LEVELS OF RADON IN
MY HOME?
The following represents our opinion, based on our
understanding of the radon issue from several sources.
| A... If the house tests above 4 pCi/L most experts
agree it is prudent to install a system that can permanently reduce your
families exposure to radon. |
| B... If the house tests below 4 pCi/L most experts
agree that there is a relatively low probability of significant health
risk at this low level of exposure. However, we recommend retesting the
radon levels once you move in, to verify this low reading. Industry
surveys show that up to 30% of the radon tests in real estate transactions
are subject to some ventilation. LET THE BUYER BEWARE. We once
tested a house, that measured 168 pCi/L in a child's bedroom. The selling
agent ordered a retest by a tester known to test on the second floor with
the windows open. He told my clients the house only measured 3.5 pCi/L and
they didn't have a radon problem. Although he never gave my clients a
written report stating this. |
| C... If the house tests between 4 and 20 pCi/L
there is no need for immediate panic, but you will have to make some
difficult decisions. About 50% of the houses we test fall in this gray
area. The national average
is 1.5 pCi/L and outside air measures about 0.35 pCi/L. The closer to 4 or
20 pCi/L the easier the decision should be. The most difficult decisions
are in the 10 to 12 pCi/L range. |
10. WHAT OTHER FACTORS SHOULD I LOOK AT IN
DECIDING WHETHER TO MITIGATE OR NOT?
| Cigarette smokers should keep their exposure to
radon as low as possible. Smokers have eight times the risk from radon as
non smokers. Smokers who reduce their radon exposure from 6 pCi/L to 2 pCi/L,
will receive as much beneficial risk reduction as the non smoker who
reduces their exposure from 34 pCi/L to 2 pCi/L. |
| If the house was tested in an infrequently used
basement. It may have measured a radon level that is two to three times
the actual level you are exposed to, spending most of your time upstairs.
|
| You can reduce your families annual radon exposure
about 40%, if you open the basement windows a few inches to allow cross
ventilation from May till September. This may be appropriate for slightly
elevated houses that don't need year round reductions. |
| People with young children should be more concerned
with the possible consequences of radon exposure 20 years from now than
someone in their late sixties or seventies. |
| Families with a hereditary predisposition of cancer
should be more concerned about radon exposure than families who don't have
any history of cancer. |
| If you work for a company that might transfer you
in the future, our employer probably will hire a relocation company to
purchase your home. Today, most relocation companies insist that the house
test below 4 pCi/L before they will buy it. Some buyers have adopted this
position; anything below 4 pCi/L is fine while anything above 4 pCi/L is
unacceptable. This unfortunate misinterpretation of EPA guidance, could
cause you to pay for a radon mitigation system when selling your home. At
this time your family would not receive any benefit from the radon
reductions. |
| The decision, What to do about radon? is a personal
choice that only you can make. Some people feel it is best to reduce as
many of life's risks as they can. Other people feel the money spent
installing and operating a radon mitigation system on a moderately
elevated home could be put to better use, having regular family medical
and dental check ups, or making other safety improvements in their home.
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11. WHAT IF, I DECIDE TO REDUCE THE RADON LEVELS
IN MY HOME?
| If you feel the radon levels are high enough to
justify installing a radon mitigation system, we recommend installing a
good quality, durable, energy efficient system. It is best to have
different
mitigation contractors bid on installing a system. |
| All too often the sellers or their agents end up deciding,
who will do the work, and how it will be done. Their main concern is that
it be installed as cheaply as possible to get the radon levels down below
4 pCi/L for the retest. Often they have the contractor who installed the
system, do the retesting to verify it is below 4 pCi/L, before he gets
paid. This could create a possible conflict of interest. |
| One other very important factor is to make certain that the mitigation
contractor has a current license. |
12. WHAT SHOULD I LOOK FOR IN A PROPERLY INSTALLED
SYSTEM?
| A... Install all fans outside the living area of
the house, so all interior piping is under negative pressure. Many
contractors find it cheaper and easier to put the fan in the basement near
an existing electrical outlet. Often these fans and piping develop leaks.
This could allow the system to start pulling the thousands of pCi/L of
radon out of the ground and blow it into the basement or crawlspace; thus
making the radon levels in the house higher than they where originally.
|
| B... The high radon concentration air blowing from
the fan should discharge above the roof, or at least ten feet from any
doors, windows or decks. No one wants to breathe hundreds or thousands of
pCi/L coming from these fans. |
| C... Dig the suction pit under the floor as large
as possible, or make sure it intersects the void beneath a grade-beam
foundation. |
| D... Seal crawlspaces with a gas membrane, made of
cross-laminated polyethylene, placed between two layers of 30 lb. tar
paper, to protect it from damage. Make sure the membrane is tightly
fastened to the foundation walls, with plywood strips and sealed with
industrial grade urethane caulking. It is cheaper to install one layer of
regular polyethylene directly over the soil, and fasten it to the walls
with duct tape, glue or caulking. This method will reduce the radon
levels, but the single layer of regular polyethylene gets torn when
someone crawls across it. Duct tape or glue usually falls off the wall
within a month or so. When this happens, the system will still keep the
radon levels down, but the fan will start pulling large amounts of heated
air out of the house. The added cold air could subject the crawlspace
plumbing to freezing and increase the cost of heating your home as much as
$200.00 to $300.00 a year. This unnecessary loss of heat could add up to
$20,000.00 to $30,000.00 over the hundred year life of the house. The
money saved on the initial installation might not be such a bargain after
all. |
| E... Caulk the large cracks and joints in the
concrete floor slab to prevent unnecessary heat loss. |
| F... Install a manometer or warning device to alert
you if anything goes wrong with the system. |
| G... Permanently label all systems, with the
contractors name, phone number, operation and maintenance instructions and
a place to note all radon test results. The people living in the house 15
to 75 years from now will need to know what this system is, and why it is
needed. |
13. WHO SHOULD PAY TO GET THE RADON REDUCED?
| If you are buying a house, this is strictly a
matter of negotiation for which there are no hard and fast rules. Some
people will choose to follow one of the GOLDEN RULES, Do unto others as
you would have them do unto you, or He who has the gold makes the rules.
No matter who ends up paying for the system, it is in your best interest
that you be the one to select the contractor and specify how the work will
be done. If you leave these decisions to others you might not end up with
the type of system you want to have. Most contractors will give you a
written bid of exactly how much the system will cost when you have them
install it. Do not worry if the radon can be successfully reduced; this is
a sure thing. In most cases, contractors will guarantee that they will
reduce the levels to below 4 pCi/L. Properly installed systems usually get
the radon down to below 2 pCi/L and sometimes even below 1 pCi/L. We have
tested several houses that originally measured more than 100 pCi/L, that
where mitigated to levels below 2 pCi/L. |
14. HOW MUCH DOES IT COST TO OPERATE THESE
SYSTEMS?
| Most systems are powered by a 90 watt fan that use
less than $52.00 worth of electricity a year. These fans should last about
14.7 years and presently cost $125.00 to replace. If the system is
properly installed and well sealed, there shouldn't be any noticeable
increases in the heating bills. However, if the cracks and joints in a
finished basement cannot be sealed, the heating cost might increase
slightly. Check this on a cold day by feeling the amount of warm air
blowing from the fan. |
15. HOW CAN I LEARN MORE ABOUT RADON?
| The EPA's hotline at 1 800-SOS-RADON will be happy
to answer your questions and send you their pamphlets about radon. They
can send you a list of radon contractors and tell you how to get their
technical publications about radon and radon mitigation. |
| You can call the local Department of Health.
EPA's Position on
Radon
EPA'S Radon
Publications
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Your local library might have some of the following
books.
| The Indoor Radon Problem...Douglas E. Brookins
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| Radon The Invisible Threat..Michael Lafavore
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| Radon a Homeowner's Guide (Consumer Reports
Books)...Bernard Cohen |
| Radon and its Decay Products...William W.
Nazaroff & Anthony V. Niro, Jr. |
| Radiation Hormesis......T.D. Luckey CRC Press
|
| Health Risks of Radon and Other Internally
Deposited Alpha-Emitters...National Academy Press |
| Health Physics....Pergamon Press The Radiation
Protection Journal |
| Radon, Radium and Uranium in Drinking
Water...Richard Cothern & Paul A. Rebers |
| Radon in Ground Water...Barbara Graves
Radiation, Science & Health
http://cnts.wpi.edu/rsh/ RSH was organized by independent individuals,
knowledgeable of radiation health effects science, and associated public
policies. They know that data is misrepresented, and public funds wasted,
to support radiation protection policy, that provides no public health
benefit.
Comparing Guideline Levels for Radon in Existing Homes
*
| USA EPA
(Environmental Protection Agency) |
4.0 pCi/l |
| Canada |
21.6 pCi/l |
| Sweden |
10.8 pCi/l |
| ICRP
(International Commission on Radiation Protection) |
16.2 pCi/l |
| WHO
(World Health Organization) |
10.8 pCi/l |
| NCRP
(National Council on Radiation Protection) |
8.0 pCi/l |
*assuming 50% equilibrium and converting from Working Levels to pCi/l
where needed. |
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