Testing for Radon?
How to Test Your Home
You can't see radon, but it's not hard to find out if you
have a radon problem in your home. All you need to do is test
for radon. Testing is easy and should only take a few minutes of
your time.
The amount of radon in the air is measured in "picoCuries per
liter of air," or "pCi/L." Sometimes test results are expressed
in Working Levels (WL) rather than picoCuries per liter (pCi/L)
(4 pCi/L equals to 0.016 WL). There are many kinds of low-cost
"do-it-yourself" radon test kits you can get through the mail
and in hardware stores and other retail outlets. If you
prefer, or if you are buying or selling a home, you can hire
a qualified
tester to do the testing for you. You should first
contact your
state radon office about obtaining a list of qualified
testers. You can also contact a private radon proficiency
program for lists of privately certified radon professionals
serving your area. For links and information, visit
www.epa.gov/radon/radontest.html .
There are Two General Ways to Test for Radon:
SHORT-TERM TESTING:
The quickest way to test is with short-term tests. Short-term
tests remain in your home for two days to 90 days, depending on the
device. "Charcoal canisters," "alpha track," "electret ion chamber,"
"continuous monitors," and "charcoal liquid scintillation" detectors
are most commonly used for short-term testing. Because radon levels
tend to vary from day to day and season to season, a short-term test
is less likely than a long-term test to tell you your year-round
average radon level. If you need results quickly, however, a
short-term test followed by a second short-term test may be used to
decide whether to fix your home.
How To Use a Test Kit:
Testing is easy and should only take a few minutes of your
time.
Follow the instructions that come with your test kit. If you
are doing a short-term test, close your windows and outside
doors and keep them closed as much as possible during the test.
Heating and air-conditioning system fans that re-circulate air
may be operated. Do not operate fans or other machines
which bring in air from outside. Fans that are part of a
radon-reduction system or small exhaust fans operating only for
short periods of time may run during the test. If you are
doing a short-term test lasting just 2 or 3 days, be sure to
close your windows and outside doors at least 12 hours before
beginning the test, too. You should not conduct short-term tests
lasting just 2 or 3 days during unusually severe storms or
periods of unusually high winds. The test kit should be
placed in the lowest lived-in level of the home (for example,
the basement if it is frequently used, otherwise the first
floor). It should be put in a room that is used regularly (like
a living room, playroom, den or bedroom) but not your kitchen or
bathroom. Place the kit at least 20 inches above the floor in a
location where it won't be disturbed - away from drafts, high
heat, high humidity, and exterior walls. Leave the kit in place
for as long as the package says. Once you've finished the test,
reseal the package and send it to the lab specified on the
package right away for analysis. You should receive your test
results within a few weeks.
LONG-TERM TESTING:
Long-term tests remain in your home for more than 90 days. "Alpha
track" and "electret" detectors are commonly used for this type of
testing. A long-term test will give you a reading that is more
likely to tell you your home's year-round average radon level than a
short-term test.
EPA Recommends the Following Testing Steps:
Step 1. Take a short-term test. If
your result is 4 pCi/L or higher take a follow-up test (Step 2)
to be sure.
Step 2. Follow up with either a long-term
test or a second short-term test:
- For a better understanding of your year-round average
radon level, take a long-term test.
- If you need results quickly, take a second short-term
test.
The higher your initial short-term test result, the more
certain you can be that you should take a short-term rather than
a long-term follow up test. If your first short-term test result
is more than twice EPA's 4 pCi/L action level, you should take a
second short-term test immediately.
Step 3. If you followed up with a long-term
test: Fix your home if your long-term test result is 4 pCi/L or
more. If you followed up with a second short-term test:
The higher your short-term results, the more certain you can be
that you should fix your home. Consider fixing your home if
the average of your first and second test is 4 pCi/L or higher.
What Your Test Results Mean
Test your home now and save your results. If you
find high radon levels, fix your home before you decide to
sell it.
The average indoor radon level is estimated to be about 1.3
pCi/L, and about 0.4 pCi/L of radon is normally found in the
outside air. The U.S. Congress has set a long-term goal that
indoor radon levels be no more than outdoor levels. While this
goal is not yet technologically achievable in all cases, most
homes today can be reduced to 2 pCi/L or below.
Sometimes short-term tests are less definitive about whether
or not your home is above 4 pCi/L. This can happen when your
results are close to 4 pCi/L. For example, if the average of
your two short-term test results is 4.1 pCi/L, there is about a
50% chance that your year-round average is somewhat below 4
pCi/L. However, EPA believes that any radon exposure carries
some risk - no level of radon is safe. Even radon levels below 4
pCi/L pose some risk, and you can reduce your risk of lung
cancer by lowering your radon level.
If your living patterns change and you begin occupying a
lower level of your home (such as a basement) you should retest
your home on that level.
Even if your test result is below 4 pCi/L, you may want to
test again sometime in the future.
Radon and Home Sales
More and more, home buyers and renters are asking about radon
levels before they buy or rent a home. Because real estate sales
happen quickly, there is often little time to deal with radon and
other issues. The best thing to do is to test for radon NOW and save
the results in case the buyer is interested in them. Fix a problem
if it exists so it won't complicate your home sale. If you are
planning to move, call your state radon office
for EPA's pamphlet "Home
Buyer's and Seller's Guide to Radon," which addresses some
common questions. You can also use the results of two
short-term tests done side-by-side (four inches apart) to decide
whether to fix your home.
During home sales:
- Buyers often ask if a home has been tested, and if elevated
levels were reduced.
- Buyers frequently want tests made by someone who is not
involved in the home sale. Your state radon office can assist
you in identifying
a qualified
tester.
- Buyers might want to know the radon levels in areas of the
home (like a basement they plan to finish) that the seller might
not otherwise test.
Today many homes are built to prevent radon from coming in. Your
state or local area may require these radon-resistant construction
features. If you are buying or renting a new home, ask the owner or
builder if it has radon-resistant features. The EPA recommends
building new homes with radon-resistant features in high radon
potential (Zone 1) areas. Even if built radon-resistant, every new
home should be tested for radon after occupancy. If you have a
test result of 4 pCi/L or more, you can have
a qualified
mitigator easily add a vent fan to an existing passive system
for about $300 and further reduce the radon level in your home.
For more information, refer to
EPA's Map of Radon
Zones and other useful EPA documents on radon-resistant new
construction (see
publications).
Radon Testing
This section will help you to learn:
- When you do and do not need a professional radon test
- Where to find a qualified professional, and how to evaluate
qualifications
- How to conduct a proper radon evaluation yourself
- How to evaluate a radon test result.
After reading this section, you may also wish to visit our
Radon FAQ page.
Do I Need a Professional Tester
Only if one or more of these conditions applies:
- You are not in control of the house, and need help to be
certain that the test conditions were maintained. This is
especially important if the person who does control the house
has a vested interest in having the radon result look good.
- You need a test with legal standing. That is, you have to
prove something to someone other than yourself.
- You need results in a hurry (say less than one week from
start to finish).
Notice that all of these conditions
probably hold if you are a homebuyer.
Hiring a Professional
In Michigan, the definitive source for names of qualified radon
testers has for years been the US EPA (Environmental Protection
Agency) Radon Measuring Proficiency list. If you hired someone with
an RMP listing, in theory you got:
- A technician trained in conducting and evaluating radon
tests, and undergoing continuing education and periodic written
tests conducted by the EPA
- Guaranteed adherence to EPA-approved test procedures
- Equipment that met EPA standards for accuracy in regular
audits
- A comprehensive Quality Assurance Program in the tester's
company
In Ohio and some other states, the state government issues radon
licenses, superseding and preempting the EPA. Some states even have
testing protocols that are different from those generally accepted
elsewhere; the others just mandate that the standard protocols be
followed.
As of October 1, 1999, the EPA ended the RMP list, and sort of
(but not really) turned it over to two organizations: the
National
Environmental Health Association (NEHA) and
National Radon Safety
Board (NRSB). EPA considers certifications from either of these
organizations to be equivalent to its own listings.
So what's a consumer to do? Here are three ideas for sorting out
the radon testers:
- Look for someone who is certified by NEHA or NRSB. Also
check that the tester's company is specifically certified for
analyzing data from the specific measurement device used. [Some
companies are only listed as "qualified" to set and retrieve a
canister to be analyzed by a certified third party lab. Those
testers should not be producing test reports; these should come
from the accredited laboratory.]
- If the tester is not certified, that does not necessarily
mean that he/she is any less competent or reliable. It's just
that you need to do some additional checking yourself. Obviously
the tester's experience and reputation count for a lot. You
should also make sure that the specific instrument being used in
your test was calibrated within the past 12 months. Ask for a
certificate, and compare to the device serial number. [See next
point.]
- Because of the conflict of interest, think hard before
hiring a firm that also does radon fixing. We include ourselves
in that statement!
We know of only two types of test device that are impossible for
a tester to rig to give false high radon readings: activated
charcoal or scintillation cell monitors, both of which are are
analyzed by a third party lab. All other test devices, including
other laboratory-type devices, can be forced to produce falsely high
radon readings.
Worse yet, the calibration constants for "Electret" devices and
even some Continuous Radon Monitors (CRMs) can easily be fudged by a
contractor to produce any result he wants. High for the initial test
that says there is a problem, then low for the test afterward to say
that it has been fixed.
Until recently, it was thought that CRMs manufactured by
Honeywell or Sun Nuclear could not be field-rigged. That's one
reason why we use purchased only Honeywell monitors for our own
testing. No possibility of any hanky-panky. However, in May 2000,
the president of a company that produces very highly-regarded CRMs
called to inform us that even the Honeywell/Sun Nuclear models can
be rigged by fiddling with the internal DIP switches. He also stated
that some contractors had been caught playing this game. We haven't
tried this out, but our curiosity and tinker-glands are certainly
aroused!
Conducting a Radon Evaluation Yourself
If you decide to do the test yourself, we suggest avoiding
hardware store kits, even if they claim to be EPA approved." For
less money, you can get a higher quality kit from us or from your
county health departments. The price of $20 includes all shipping
and lab fees; the lab will send you a written report.
Good advice on where, when & how to conduct the test is available
from EPA pamphlets. We include a copy if you buy the kits from us;
otherwise call the Radon
Hotline or download from the EPA website. See also the
Radon FAQ page.
In general, your first test will take anywhere from 2 to 7 days,
as specified by the manufacturer. DO NOT use "long term" test kits
as your first step; these take anywhere from 3-12 months, too long
to wait.
Evaluating
Never take action based on a single measurement. You always want
two results, and they should agree with each other. The EPA suggests
two screening tests run side-by-side, or two sequentially in the
same location. Most people prefer the former method.
Note: EPA makes an exception for measurements done with
Continuous Radon Monitors (electronic data loggers) in a real
estate transaction. They advise that one "high" CRM test is
enough for action.
If your short term tests agree and their average is at or above
4.0 picoCuries/liter (the EPA Action Level), the EPA says that you
should take some action to reduce your radiation exposure.
Because screening tests are subject to vagaries of weather, in
marginal situations you might wish to conduct a year-long test
before committing to a major expenditure. It's also possible to
simulate a year-long test in as little as 90 days.
Note: the EPA
defines a long term test as one that "remains in your home for
more than 90 days." Okay, okay. 90 days plus 1 minute is longer
than 90 days.
At the bottom line is the Golden Rule of radiation safety: ALARA,
which stands for As Low As Reasonably Achievable. Only you can know
what is "reasonable" for your situation. Much depends on your
family's medical history (cancers increase the risk) and your home's
function (basement bedrooms or playrooms increase the risk).