NRSB RMS key terms

A colorless, odorless, radioactive gas produced by the decay of radium-226, which itself comes from uranium-238 in soil and rock. It is the leading cause of lung cancer among nonsmokers.

Short-lived radioactive isotopes formed when radon decays, including polonium-218, lead-214, bismuth-214, and polonium-214. These solid particles attach to dust and are inhaled, delivering radiation dose to lung tissue.

A radioactive isotope in the uranium-238 decay chain that decays into radon-222. Its presence in soil, rock, and building materials is the primary source of indoor radon.

The parent isotope of the uranium-238 decay series. It occurs naturally in rock and soil and ultimately produces radium-226 and radon-222 through a series of radioactive decays.

A unit of radon concentration equal to one trillionth of a curie per liter of air. In the United States, radon levels are typically reported in pCi/L; the EPA action level is 4 pCi/L.

The SI unit of radon activity concentration, equal to one radioactive decay per second per cubic meter of air. One pCi/L equals 37 Bq/m³.

A unit of radon decay product concentration defined as any combination of short-lived radon progeny in one liter of air that will result in the emission of 1.3 × 10^5 MeV of alpha energy.

A unit of cumulative radon decay product exposure equal to exposure to one working level for 170 hours, the typical number of working hours in a month.

The ratio of the actual radon decay product concentration (in WL) to the potential alpha energy concentration of the radon present, expressed as a fraction. It indicates how closely decay products are in equilibrium with radon.

A radon concentration at which a mitigation or further testing decision is recommended. In the U.S., EPA recommends fixing a home if the radon level is 4 pCi/L or higher.

The process of reducing radon concentrations in a building through techniques such as sub-slab depressurization, sealing, or ventilation. It is recommended when test results meet or exceed the action level.

A radon mitigation method that uses a fan and piping to draw soil gas from beneath a building's foundation and vent it outdoors, reducing the pressure that drives radon indoors.

A specialized fan installed in a radon mitigation system to create negative pressure under the slab or in the soil and exhaust radon-laden soil gas to the outdoors.

Testing conditions in which all exterior doors and windows are kept closed, except for normal entry and exit, for at least 12 hours before and during the radon test. These conditions simulate typical occupied use.

A radon measurement conducted for a period of 2 to 90 days, depending on the device. It provides a quick indication of radon levels but may be affected by seasonal or weather variations.

A radon measurement conducted for more than 90 days, typically 3 to 12 months. It provides a more representative annual average radon concentration than a short-term test.

A device that does not require continuous power to operate and integrates radon exposure over time, such as an alpha track detector or electret ion chamber. It is typically deployed for short- or long-term testing.

A device that requires electrical power to operate and continuously samples or monitors radon, such as a continuous radon monitor. It can provide real-time or near-real-time concentration data.

A passive radon measurement device that uses a plastic film to record alpha particle tracks produced by radon decay. The tracks are chemically etched and counted to determine the integrated radon concentration.

A passive radon measurement device that uses an electrically charged electret to collect ions produced by radon decay. The voltage change on the electret is measured to calculate radon concentration.

An active radon measurement device that continuously samples air and records radon concentration at set intervals, often hourly. It can provide detailed data on radon fluctuations during the test period.

A passive radon measurement device containing activated charcoal that adsorbs radon. After exposure, the canister is analyzed in a laboratory to determine the average radon concentration during the deployment period.

A laboratory analysis method in which a sample is mixed with a scintillation cocktail that emits light when struck by radiation. It is used to measure radon or radon decay products collected on a filter or in a canister.

Planned and systematic activities implemented to ensure that radon measurement results meet specified quality requirements, including training, standard operating procedures, and equipment calibration.

Operational techniques and activities used to verify that measurement results meet quality requirements, such as duplicate measurements, blanks, spikes, and calibration checks.

The process of adjusting or verifying a measurement device against a known standard or reference to ensure accurate readings. Regular calibration is required for reliable radon measurements.

A quality control sample to which a known amount of radon or a radioactive standard is added, used to assess the accuracy and recovery of a measurement or analysis method.

A quality control sample that contains no added radon or is otherwise free of the analyte, used to detect contamination or background interference in the measurement process.

A second measurement taken at the same location and time as the primary measurement, used to assess precision and variability of the measurement method.

A measurement performed with a second, independent device or method at the same location to verify the results of the primary measurement.

A package containing a radon measurement device, instructions for deployment, and laboratory analysis, used by homeowners or professionals to measure radon levels.

An estimate of the likelihood that a building in a given area will have elevated indoor radon concentrations, based on geology, soil, and building characteristics.

The movement of radon from soil or other sources into a building through openings such as cracks in the foundation, sump pits, or utility penetrations, driven by pressure differences.

The extent to which a mitigation system creates a negative pressure field beneath a building's foundation, used to evaluate the effectiveness of sub-slab depressurization.

Building techniques that prevent radon entry in new homes, such as installing a gas-permeable layer under the slab, sealing openings, and providing a vent pipe for future mitigation.

An individual who has been trained and certified to conduct radon measurements according to established protocols and quality assurance requirements.

An individual trained and certified to design and install radon mitigation systems to reduce indoor radon concentrations.

The radon concentration of 4 pCi/L at which the U.S. Environmental Protection Agency recommends that homeowners take action to reduce radon levels.

The radioactive disintegration of radon-222 into daughter products, emitting alpha particles and eventually leading to stable lead-206.