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Radon Terms and Glossary

Unless you're an expert on Radon, or vocabulary, it's likely that you'll come across a term used on this site that you don't understand. To help out, we've compiled a complete list of terms and definitions that pertain to Radon, testing, mitigation and more. If you encounter a word on the site that you don't know, feel free to come back here to find out what it means.


Accuracy - A particular range or true value that allows one to determine how accurate a measurement is.

Action Level - The designated measurement at which consumers and businesses should take action to reduce radon levels in a residence. In the US, the EPA has set the action level to 4.0 pCi/L. The action levels for other countries vary.

Active Radon Testing or Measurement Device - A testing system that includes several components - sampler, detector, measurement device - which operate as a single unit.

Alpha Particle - A single particle comprised of two neutrons and two protons that is emitted from the nucleus of a radioactive isotope during the decay process. It is radon alpha particles that make it into the lungs and cause severe damage.

Background Measurements - Excess measurements detected by active or passive detectors. The background measurements are subtracted from field measurements, which reveals the true concentration of radon.

Bias - A consistent error in test results.

Blank Sample - The control in a lab test, otherwise the sample taken with an unexposed testing device that is submitted to a lab. The control is used to identify background values which are used to determine the true radon concentration in a residence.

Blind Spikes- Detectors that have been exposed to concentrations of radon, which are submitted for analysis without a label. They are often used to determine the accuracy of a test.

Calibrate - When a testing device collects readings or measurements it is necessary to correct various elements beforehand to ensure accurary, such a process is called calibration.

Carcinogen - A dangerous substance or radionuclide that is directly involved in the contraction of cancer. Long-term exposure to a carcinogen heavily increases the risk of cancer.

Continuous Monitoring Device (Radon Detector) - A device that measures the current or average levels of Radon in a residence over an extended period of time. They are called continuous because of their prolonged testing requirements.

Curie (Ci) - The rate of measurement in radioactivity, or more specifically the rate of decay for a single gram of radium.

Department of Health (DOH) - A cabinet-level department in the federal government that is dedicated to preserving and securing the health of all Americans in the country.

Exposure Time - Also referred to as the exposure period, it refers to the length of time a testing device must be in contact with the air to acquire an accurate measurement of radon concentration.

Heat Recovery Ventilator (HRV) - Also known as an air-to-heat exchanger this device introduces fresh air into a residence while cooling or heating it simultaneously. In that respect, it creates ventilation to the outside by reducing dirty or contaminated air.

Integrated Testing Device - A type of test device that measures the average radon levels over a period of time.

Ionization - Refers to the process in which a neutral atom becomes either negatively or positively charged after losing or gaining an electron.

Long Term Radon Test - A radon testing kit that calls for a long testing period usually in excess of 90 days. Because long term tests return the average radon level for the period tested, they are considered more accurate.

Quality Assurance - A system designed to produce test results that can serve as a standard. In other words they are scientifically defensible and have strict precision, bias and accurary readings.

National Average - The nationally accepted levels of concentrated radon indoors or out. The average indoor level of Radon gas is about 1.3 pCi/L, while the average of outside levels is approximately 0.4 pCi/L.

National Certified list (NEHA/NRSB) - A list of nationally accepted and professionally certified contractors. Ensure a contractor is on this list before hiring them to perform radon mitigation work in your home.

Nuclear Regulatory Commission - An independent agency of the US government charged with overseeing the safety of nuclear and radioactive material handling. As such this includes monitoring nuclear reactor safety and security, licensing and renewal, and spent fuel disposal. Of course, the commission is also in charge of radioactive material safety, hence their involvement with radon poisoning.

Short Term Radon Test - A radon testing kit that calls for a short testing period that ranges anywhere from a 2 to 90 day period. Because radon levels can fluctuate over time, and can be changed by several factors a short term radon test is not as accurate as a long term one. Therefore, if a short term tests returns readings higher than 4 pCi/L, a follow-up long term test should be conducted.

Passive Radon Testing or Measurement Device - A testing system that includes several components - sampler, detector, measurement device - which do not operate as a single unit.

Picocurie (pCi) - A unit of measurement that equates to one trillionth of a Curie.

Picocuries Per Liter (pCi/L) - The unit of measurement that specifies the decay in seconds within a volume of one liter of air.

Radon (Rn) A dangerous gaseous element that is formed during the radioactive decay of radium atoms. It is so dangerous because it is colorless, odorless, and there are no short term symptoms of exposure to it.

Radon Contractor - Also known as a Mitigation Service Provider, Radon Contractors are certified professionals that understand how to test and remove radon from a residence or business.

Radon Gas - Radioactive gas also referred to as “radon” that is colorless, odorless, tasteless and invisible. Because it is comprised of a single atom it can easily penetrate building materials or layers such as leather, paper, plastic, paints, sheetrock, concrete blocks, mortar and even insulation. Radon gas is nine times denser than air which is why it is notorious for seeping into the lowest levels of a home.

Radon Mitigation - The process, of which there are several, used to remove concentrated levels of radon from a home, residence or business.

Radon Mitigation System - A series of devices or complete system that is designed to aerate a home and remove concentrated radon gas. If levels test higher than 4 pCi/L, it is definitely recommended that you hire a certified contractor or tester to complete further examinations and possibly to install a mitigation system.

Time Integrated Sampling - A test that is performed over a certain period of time, generally anywhere from 2 days up to more than a year. The results offer the average value of radon concentration during that time period.