| Testing for Radon |
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| Types of Radon Tests |
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Several different measurement methods may be used to determine the radon concentrations in structures. Each method has its own advantages and disadvantages. Users must decide which method is best suited to their situation. The Public Health Division recommends a method which will provide an annual average radon concentration in the living area of a structure. The following details the characteristics of the methods, pointing out some of the advantages and disadvantages of each one. The following information is intended to guide the user in making an informed selection of a measurement method.
| Short-term tests last from 2-90 days whereas long-term tests last from 91 days to 1 year. Various other dynamic testing methods are also available but are generally much more expensive to use. |
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Activated Carbon Adsorption (AC) & Charcoal Liquid Scintillation (LS) - Short Term
Both of these methods absorb radon gas on activated charcoal but different equipment is used for analysis. The detectors for these methods consist of various configured containers filled with a measured amount of activated charcoal. The container is perforated or screened and has a filter to keep out radon decay products. All charcoal adsorbers are stored in air-tight containers before and after sampling.
Charcoal adsorbers are installed from two to seven days. At the end of testing, the adsorber is resealed and returned to the vendor for processing and evaluation.
- Advantages
- Low cost for services; costs may range from $10 to $25 for each detector.
- Practical for screening purposes over a short time period.
Disadvantages
- Some charcoal adsorbers are more sensitive than others to temperature and humidity.
- Limited to short term testing.
Alpha-Track Detection (AT) - Long Term
The detector is a small sheet of special plastic material enclosed in a container with a filter-covered opening. The radon gas that enters the container decays, emitting alpha particles. The particles strike the plastic sheet, leaving tracks that can be chemically enhanced and counted using a microscope or an automated counting system.
The detectors are installed according to instructions supplied by the vendor. They are left for periods from one to three months for screening and from three to twelve months for long-term evaluations. At the end of the desired testing period, they are returned to the vendor for processing and evaluation.
Advantages
Relatively low-cost services ranging from $15 to $30 for each detector.
Can measure the long-term average concentrations over a twelve-month period.
Disadvantages
Relatively long measurement period necessary; three months is the recommended minimum for most detectors.
Continuous Radon Monitoring (CR)
There are three types of CR monitors used for radon measurements: 1) Scintillation, 2) Ionization Chamber, and 3) Solid-State Detection. This type of radon monitoring follows the ambient radon levels within a short time lag due to the inherent delay of the radon decay products.
Advantages
Follows the variations in radon levels.
Provides radon data on location.
Has the highest accuracy and precision over short measurement periods.
Disadvantages
High cost for service requiring a professional to perform the measurement.
Limited primarily to short-term testing.
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| Performing a Radon Test Yourself |
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The Environmental Protection Agency recommends the following:
Step 1. Take a short term radon test. If your result is 4 pCi/L or higher, take a follow up test to be sure.
Step 2. Depending on the results of your first test, follow up with either a long-term test or a second short term test. If your short-term test results were 8 pCi/L or above, follow up with another short-term test. If your short-term test results are below 8 pCi/L follow up with a long-term test. Long-term tests will give you a more accurate reading of your year-round average radon level.
Step 3. If the average of your first two short-term tests is 4 pCi/L or above, or the result of your long-term test was 4 pCi/L or above, fix your home.
If your test results are below the action level of 4 pCi/L, you may want to retest in the future, especially if you start occupying a lower level of the home.
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| What Your Test Results Mean |
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Radon is measures in picocuries per liter (pCi/L). The EPA has estimated that the average indoor radon level in the U.S. is 1.3 pCi/L. The average radon concentration in the outdoor air in the US has been estimated to be about 0.4 pCi/L. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels. While this goal is not technologically achievable in all cases, most homes can be reduced to 2 pCi/L or below.
It is important to keep in mind that there is no “safe level” of radon exposure-any radon exposure carries some risk. Even radon levels below 4 pCi/L pose some risk. You can reduce your risk of lung cancer by lowering your radon level.
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| Radon Measurement & Mitigation Companies |
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The following is a list of companies or individuals that provide radon measurement or mitigation services to Oregon. Some companies have been certified by the National Environmental Health Association (NEHA) or the National Radon Safety Board (NRSB ).
This list should be used for informational purposes only and is not intended to be an endorsement by the Oregon Department of Human Services of any testing device or company. These organizations are not the only sources of radon testing devices or services.
There may be additional companies listed in your local phone book under "Radon Testing". There are additional organizations outside Oregon that can provide radon testing devices or services, and testing devices may be available through hardware stores.
Before purchasing, one should verify that the device or service meets the current requirements of the national certifying organizations, e.g. NEHA or NRSB.
The office of Radiation Protection Services has information available and can provide upon request a current list of all certified companies in neighboring states or nationwide that service Oregon. The following companies can provide radon kits and/or perform radon measurements in accordance with EPA protocols:
Measurement Companies (pdf)
Mitigation Companies (pdf)
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