The following information provides details about radon testing methods, including the advantages and disadvantages of each one. This information is intended to guide the user in making an informed selection of a measurement method.
Short-term Tests: Activated Carbon Adsorption (AC) & Charcoal Liquid Scintillation (LS)
Most short term radon tests will use activated charcoal to absorb the radon gas in the air. Various short terms tests kits will include some type container filled with activated charcoal, usually perforated or screened and has a filter to keep out radon decay products. At the end of testing, the absorber is resealed and returned to the vendor for processing and evaluation
• Quick and easy. Testing usually takes between 2-90 days depending on the type of test.
• Low cost for services; costs may range from $10 to $25 per test kit.
• Practical for screening purposes over a short period of time.
• Some charcoal absorbers are more sensitive that others to temperature and humidity.
• Less likely to tell you a year-round average radon level.
Long-term Tests: Alpha-Track Detection (AT)
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.
• Relatively low-cost services ranging from $15 to $30 for each detector.
• More likely to tell you year-round average radon levels.
• Relatively long measurement period (3 months is the recommended minimum for most long-term kits).
Professional Testing: Continuous Radon Monitoring (CR)
There are three types of CR monitors used for radon measurements, usually by radon measurement professionals. The test types are: 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.
- Follows the variations in radon levels.
- Provides radon data on location.
- Has the highest accuracy and precision over short measurement periods.
- High cost for service requiring a professional to perform the measurement.
- Limited primarily to short-term testing.