Radon testing is easy and the only way to find out if you have a radon problem in your home.
a. Types of Radon Devices
Since you cannot see or smell radon, special equipment is needed to detect it. When you're ready to test your home, you can order a radon test kit by mail from a qualified radon measurement service provider or laboratory. You can also hire a qualified radon tester, very often a home inspector, who will use the radon device(s) suitable to your situation. If you hire a home inspector, make sure you hire a qualified InterNACHI member -- specifically, an IAC2 certified air-quality professional. The most common types of radon testing devices are listed below.
Passive radon-testing devices do not need power to function. These include charcoal canisters, alpha-track detectors, charcoal liquid scintillation devices, and electret ion chamber detectors, which are available in hardware, drugstores, and other stores; they can also be ordered by mail or phone. These devices are exposed to the air in the home for a specified period of time, and then sent to a laboratory for analysis. Both short-term and long-term passive devices are generally inexpensive. Some of these devices may have features that offer more resistance to test interference or disturbance than other passive devices. Qualified radon testers may use any of these devices to measure the home's radon level.
Active radon-testing devices require power to function. These include continuous radon monitors and continuous working-level monitors. They continuously measure and record the amount of radon and its decay products in the air. Many of these devices provide a report of this information, which can reveal any unusual or abnormal swings in the radon level during the test period. A qualified tester can explain this report to you. In addition, some of these devices are specifically designed to deter and detect test interference. Some technically advanced active devices offer anti-interference features. Although these tests may cost more, they may ensure a more reliable result.
b. General Information for All Devices
A state or local radon official can explain the differences between devices, and recommend the ones which are most appropriate for your needs and expected testing conditions.
Make sure to use a radon measurement device from a qualified laboratory. Certain precautions should be followed to avoid interference during the test period. See the Radon Testing Checklist for more information on how to get a reliable test result.
Radon Test Device Placement
The EPA recommends that testing device(s) be placed in the lowest level of the home suitable for occupancy. This means testing in the lowest level (such as a basement) which a buyer could use for living space without renovations. The test should be conducted in a room to be used regularly (such as a family room, living room, play room, den or bedroom); do not test in a kitchen, bathroom, laundry room or hallway. Usually, the buyer decides where to locate the radon test, based on their expected use of the home. A buyer and seller should explicitly discuss and agree on the test location to avoid any misunderstanding. Their decision should be clearly communicated to the person performing the test.
c. Preventing or Detecting Test Interference
There is a potential for test interference in real estate transactions. There are several ways to prevent or detect test interference:
Use a test device that frequently records radon or decay-product levels to detect unusual swings.
Employ a motion detector to determine whether the test device has been moved or if testing conditions have changed.
Use a proximity detector to reveal the presence of people in the room, which may correlate to possible changes in radon levels during the test.
Record the barometric pressure to identify weather conditions which may have affected the test.
Record the temperature to help assess whether doors and windows have been opened during the test.
Apply tamper-proof seals to windows to ensure closed-house conditions.
Have the seller/occupant sign a non-interference agreement.
Home buyers and sellers should consult a qualified radon test provider about the use of these precautions.
d. Length of Time to Test
There are two general ways to test your home for radon:
Because radon levels vary from day to day and from season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. However, if you need results quickly, a short-term test may be used to decide whether to fix the home.
The quickest way to test is with short-term tests. Short-term tests remain in your home from two days to 90 days, depending on the device. There are two groups of devices which are more commonly used for short-term testing. The passive-device group includes alpha-track detectors, charcoal canisters, charcoal liquid scintillation detectors, and electret ion chambers. The active device group consists of different types of continuous monitors.
Whether you test for radon yourself, or hire a state-certified tester or a privately certified tester, all radon tests should be taken for a minimum of 48 hours. A longer period of testing is required for some devices.
Long-term tests remain in your home for more than 90 days. Alpha-track andelectret ion chamber 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. If time permits, long-term tests (more than 90 days) can be used to confirm initial short-term results. When long-term test results are 4 pCi/L or higher, the EPA recommends mitigating the home.
e. Doing a Short-Term Test...
If you are testing in a real estate transaction and you need results quickly, any of the following three options for short-term tests are acceptable in determining whether the home should be fixed. Any real estate test for radon should include steps to prevent or detect interference with the testing device.
When Choosing a Short-Term Testing Option...
There are trade-offs among the short-term testing options. Two tests taken at the same time (simultaneous) would improve the precision of this radon test. One test followed by another test (sequential) would most likely give a better representation of the seasonal average. Both active and passive devices may have features which help to prevent test interference. Your state radon office can help you decide which option is best.
Short-Term Testing Options
What to Do Next
Take two short-term tests at the same time in the same location for at least 48 hours.
Take an initial short-term test for at least 48 hours. Immediately upon completing the first test, do a second test using an identical device in the same location as the first test.
Fix the home if the average of two tests is 4 pCi/L or more.
Fix the home if the average of the two tests is 4 pCi/L or more.
Test the home with a continuous monitor for at least 48 hours.
Fix the home if the average radon level is 4 pCi/L or more.
f. Using testing devices properly for reliable results.
If you do the test yourself:
When you are taking a short-term test, close windows and doors and keep them closed, except for normal entry and exit. If you are taking a short-term test lasting less than four days, be sure to:
Close your windows and outside doors at least 12 hours before beginning the test.
Do not conduct short-term tests lasting less than four days during severe storms or periods of high winds.
Follow the testing instructions and record the start time and date.
Place the test device at least 20 inches above the floor in a location where it will not be disturbed and where it will be away from drafts, high heat, high humidity, and exterior walls.
Leave the test kit in place for as long as the test instructions say.
Once you have finished the test, record the stop time and date, re-seal the package, and return it immediately to the lab specified on the package for analysis.
You should receive your test results within a few weeks. If you need results quickly, you should find out how long results will take and, if necessary, request expedited service.
If you hire a qualified radon tester:
In many cases, home buyers and sellers may decide to have the radon test done by a qualified radon tester who knows the proper conditions, test devices, and guidelines for obtaining a reliable radon test result. They can also:
•evaluate the home and recommend a testing approach designed to make sure you get reliable results;
•explain how proper conditions can be maintained during the radon test;
•emphasize to occupants of a home that a reliable test result depends on their cooperation. Interference with, or disturbance of, the test or closed-house conditions will invalidate the test result;
•analyze the data and report measurement results; and
•provide an independent test.
g. Interpreting Radon Test Results
The average indoor radon level is estimated to be about 1.3 pCi/L; roughly 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 for all homes, radon levels in many homes can be reduced to 2 pCi/L or below.
Radon Test Results Reported in Two Ways
Your radon test results may be reported in either picoCuries per liter of air (pCi/L) or working levels (WL). If your test result is in pCi/L, the EPA recommends you fix your home if your radon level is 4 pCi/L or higher. If the test result is in WL, the EPA recommends you fix the home if the working level is 0.02 WL or higher. Some states require WL results to be converted to pCi/L to minimize confusion.
Sometimes, short-term tests are less definitive about whether the home is at or above 4 pCi/L, particularly when the results are close to 4 pCi/L. For example, if the average of two short-term tests is 4.1 pCi/L, there is about a 50% chance that the year-round average is somewhat below 4 pCi/L.
However, the 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. You can reduce your risk of lung cancer by lowering your radon level.
As with other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, we know more about radon risks than risks from most other cancer-causing substances. This is because estimates of radon risks are based on data from human studies on underground miners. Additional studies on more typical populations are underway.
Your radon measurement will give you an idea of your risk of getting lung cancer from radon. Your chances of getting lung cancer from radon depend mostly on:
•your home's radon level;
•the amount of time you spend in your home; and
•whether you are a smoker or have ever smoked.
Smoking combined with radon is an especially serious health risk. If you smoke or are a former smoker, the presence of radon greatly increases your risk of lung cancer. If you stop smoking now and lower the radon level in your house, you will reduce your lung cancer risk.
Based on information contained in the National Academy of Sciences' 1998 report, The Health Effects of Exposure to Indoor Radon, your radon risk may be somewhat higher than shown, especially if you have never smoked. It's never too late to reduce your risk to lung cancer. Don't wait to test and fix a radon problem. If you are a smoker, stop smoking.
Go to the Radon Risk Comparison Charts
Radon Testing Checklist
For reliable test results, follow this Radon Testing Checklist carefully. Testing for radon is not complicated. Improper testing may yield inaccurate results and require another test. Disturbing or interfering with the test device or with closed-house conditions may invalidate the test results, and is actually illegal in some states. If the seller or qualified tester cannot confirm that all items have been completed, take another test.
Before conducting a radon test:
Notify the occupants of the importance of proper testing conditions. Give the occupants written instructions or a copy of this Guide and explain the directions carefully.
Conduct the radon test for a minimum of 48 hours; some test devices have a minimum exposure time greater than 48 hours.
When doing a short-term test ranging from two to four days, it is important to maintain closed-house conditions for at least 12 hours before the beginning of the test and during the entire test period.
When doing a short-term test ranging from four to seven days, the EPA recommends that closed-house conditions be maintained.
If you conduct the test yourself, use a qualified radon measurement device and follow the laboratory's instructions. Your state may be able to provide you with a list of do-it-yourself test devices available from qualified laboratories.
If you hire someone to do the test, hire only a qualified individual. Some states issue photo identification (ID) cards; ask to see it. The tester's ID number, if available, should be included or noted in the test report.
The test should include method(s) to prevent or detect interference with testing conditions, or with the testing device itself.
If the house has an active radon-reduction system, make sure the vent fan is operating properly. If the fan is not operating properly, have it (or ask to have it) repaired and then test it.
"Closed-house conditions" mean keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines which bring in air from outside. Fans that are part of a radon-reduction system or small exhaust fans operating for only short periods of time may run during the test.
During a radon test:
Maintain closed-house conditions during the entire time of a short-term test, especially for tests shorter than one week.
Operate the home's heating and cooling systems normally during the test. For tests lasting less than one week, operate only air-conditioning units which re-circulate interior air.
Do not disturb the test device at any time during the test.
If a radon-reduction system is in place, make sure the system is working properly and will be in operation during the entire radon test.
After a radon test:
If you conduct the test yourself, be sure to promptly return the test device to the laboratory. Be sure to complete the required information, including start and stop times, test location, etc.
If an elevated level is found, fix the home. Contact a qualified radon-reduction contractor about lowering the radon level. The EPA recommends that you fix the home when the radon level is 4 pCi/L or more.
Be sure that you or the radon tester can demonstrate or provide information to ensure that the testing conditions were not violated during the testing period.