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100+ Free NRSB RMT Practice Questions

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2026 Statistics

Key Facts: NRSB RMT Exam

75 questions

Exam Length (1.5 hours)

NRSB Digital Exam Information

70% (53/75)

Passing Score

NRSB RMT Exam Guidance

$120

Exam Fee (non-refundable)

NRSB

8 hours

Required Approved Training

NRSB Certification Requirements

4 pCi/L

EPA Radon Action Level

EPA Citizen's Guide to Radon

14 days

Retake Waiting Period

NRSB Digital Exam Information

4 CE credits/year

Renewal Requirement

NRSB Renewal Policy

The NRSB RMT exam certifies entry-level radon professionals — often home inspectors and field technicians — to place and retrieve radon test devices under the supervision of a certified Radon Measurement Specialist or Accredited Radon Laboratory. The virtual live-proctored exam (desktop or laptop only) has 75 single-best-answer questions in 1.5 hours; passing requires 70% (53 of 75), the fee is $120, failed attempts require a 14-day wait, and a pass is valid one year toward certification. The official curriculum weights placement and conditions most heavily (19 of 75 questions): lowest lived-in level, 20 inches above the floor, 3 feet from exterior doors/windows, 1 foot from exterior walls, and closed-building conditions starting 12 hours before tests shorter than 4 days. Other domains cover the radon decay chain and pCi/L-WL units, lung cancer risk and smoking synergy, device types (charcoal, electret, alpha track, CRM), mitigation basics, QA duplicates-blanks-spikes, EPA and state government roles, and ethics. Questions draw on current ANSI/AARST standards and EPA protocol documents. Certification requires 8 hours of approved training and renews with 4 CE credits per year.

Sample NRSB RMT Practice Questions

Try these sample questions to test your NRSB RMT exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Radon-222, the isotope of primary concern in indoor air, is produced directly by the radioactive decay of which element?
A.Uranium-238
B.Radium-226
C.Polonium-218
D.Lead-210
Explanation: Radon-222 is the immediate decay product of radium-226, a solid radioactive element found in soil and rock as part of the uranium-238 decay series.
2What is the approximate half-life of radon-222?
A.About 30 minutes
B.About 1,600 years
C.About 3.8 days
D.About 22 years
Explanation: Radon-222 has a half-life of approximately 3.8 days, long enough for the gas to migrate from soil into buildings but short enough that concentrations change quickly when entry stops.
3Radon itself is a chemically inert noble gas. Why do its decay products (progeny) deliver most of the radiation dose to the lungs?
A.The progeny are electrically charged solids that attach to airborne particles, deposit in the respiratory tract, and emit alpha radiation there
B.The progeny are gases that dissolve into the bloodstream more readily than radon
C.The progeny emit only gamma radiation, which penetrates lung tissue more deeply
D.The progeny have half-lives of thousands of years, so they irradiate the lungs for a lifetime
Explanation: Unlike inert radon gas, the short-lived progeny (polonium-218, lead-214, bismuth-214, polonium-214) are charged solid particles that attach to dust and aerosols, lodge in the lung, and irradiate sensitive tissue with alpha particles.
4One picocurie per liter (pCi/L) of radon is equal to approximately how many becquerels per cubic meter (Bq/m3)?
A.3.7 Bq/m3
B.100 Bq/m3
C.0.027 Bq/m3
D.37 Bq/m3
Explanation: The standard conversion is 1 pCi/L = 37 Bq/m3, so the EPA action level of 4 pCi/L corresponds to about 148 Bq/m3.
5Which statement best defines one Working Level (WL)?
A.The radon gas concentration that produces 1 pCi/L of progeny in one hour
B.Any combination of short-lived radon progeny in one liter of air that will release 1.3 x 10^5 MeV of potential alpha energy
C.The amount of radon inhaled by a miner during one 170-hour working month
D.The annual occupational exposure limit for radon workers set by the EPA
Explanation: A Working Level is defined as any combination of short-lived radon decay products in one liter of air that will ultimately release 1.3 x 10^5 MeV of potential alpha energy.
6Using the EPA's assumed 50% equilibrium ratio between radon gas and its progeny, a progeny concentration of 0.02 WL corresponds to approximately what radon gas concentration?
A.4 pCi/L
B.2 pCi/L
C.8 pCi/L
D.200 pCi/L
Explanation: At a 50% equilibrium ratio, 1 WL corresponds to about 200 pCi/L of radon gas, so 0.02 WL corresponds to about 4 pCi/L — which is why the EPA action level is stated as 4 pCi/L or 0.02 WL.
7What is the EPA action level at which homeowners are advised to fix their homes for radon?
A.1.3 pCi/L
B.0.4 pCi/L
C.4 pCi/L
D.20 pCi/L
Explanation: The EPA recommends fixing a home when the radon level is 4 pCi/L (0.02 WL) or higher, and to consider fixing between 2 and 4 pCi/L.
8The average outdoor (ambient) radon concentration in the United States is approximately:
A.4.0 pCi/L
B.0.4 pCi/L
C.1.3 pCi/L
D.0.02 pCi/L
Explanation: EPA publications cite an average outdoor radon level of about 0.4 pCi/L, which is also the long-term national goal for indoor air under the Indoor Radon Abatement Act.
9The national average indoor radon concentration in U.S. homes is approximately:
A.0.4 pCi/L
B.4.0 pCi/L
C.2.7 pCi/L
D.1.3 pCi/L
Explanation: The EPA cites a national average indoor radon level of about 1.3 pCi/L, compared with about 0.4 pCi/L in outdoor air.
10Which mechanism is the dominant way radon from soil gas enters most houses with elevated levels?
A.Off-gassing from stone and concrete building materials
B.Molecular diffusion through intact concrete slabs
C.Pressure-driven flow of soil gas through cracks and openings, drawn in because the lower part of the house is at slightly negative pressure relative to the soil
D.Release from municipal water supplies during showering
Explanation: Pressure-driven (advective) flow dominates: the stack effect, exhaust fans, and combustion appliances depressurize the lower levels of a house, pulling radon-laden soil gas in through cracks, joints, sump pits, and other openings.

About the NRSB RMT Exam

The NRSB Radon Measurement Technician (RMT) exam is the entry-level certification test of the National Radon Safety Board for professionals who place and retrieve radon measurement devices. Certified RMTs work under the supervision of an NRSB Radon Measurement Specialist or an NRSB Accredited Radon Laboratory within an active quality assurance program. The 75-question exam follows the NRSB course curriculum: radon science and units, health effects, test devices, placement and closed-building protocols, mitigation basics, client and laboratory relations, the role of government, and professional ethics. Candidates must first complete 8 hours of NRSB-approved classroom training, and a passing score is valid for one year toward certification.

Questions

75 scored questions

Time Limit

1.5 hours (90 minutes)

Passing Score

70% (at least 53 of 75 questions)

Exam Fee

$120 (non-refundable) (National Radon Safety Board (NRSB))

NRSB RMT Exam Content Outline

12%

Basic Radon Science & Units

Uranium-radium-radon decay chain, radon-222 half-life (3.8 days), progeny, alpha/beta/gamma radiation, pCi/L, Bq/m3, WL and WLM units, typical indoor (1.3 pCi/L) and outdoor (0.4 pCi/L) levels, soil-gas entry and the stack effect

12%

Health Effects of Radon

Progeny deposition and alpha damage to the lung, uranium miner studies and BEIR VI, ~21,000 annual U.S. lung cancer deaths, smoking synergy (62 vs 7 per 1,000 lifetime risk at 4 pCi/L), radon-in-water 10,000:1 transfer factor

12%

Radon Test Methods & Devices

Passive vs active devices: activated charcoal (2-7 days), charcoal liquid scintillation, electret ion chambers (ES/EL), alpha track (91+ days), continuous radon and working level monitors, grab samples, short-term (2-90 day) vs long-term testing

25%

Test Placement & Measurement Conditions

Lowest lived-in/occupiable level, 20-inch height, 3 ft from exterior doors/windows, 1 ft from exterior walls, closed-building conditions (12 hours before tests under 4 days), weather restrictions, real estate simultaneous/sequential protocols, interference and invalidation, schools and large buildings

7%

Mitigation Basics & Post-Mitigation Testing

Active soil depressurization, why sealing alone fails, ventilation/HRV dilution, aeration and GAC for well water, U-tube manometer monitoring, retest no sooner than 24 hours and within 30 days of installation, radon-resistant new construction

19%

Client & Laboratory Relations (QA)

Risk communication, confidentiality, follow-up testing decisions at and above 4 pCi/L, real estate negotiation and escrow, working under RMS/ARL supervision, QA plan with duplicates (~10%), field blanks (~5%), spikes (~3%), and calibration

13%

Government, Ethics & Professional Practice

EPA guidance role, Indoor Radon Abatement Act of 1988 goal, state licensure and disclosure laws, EPA consumer publications, National Radon Action Month (January), occupational exposure, conflicts of interest, NRSB code of ethics and CE requirements

How to Pass the NRSB RMT Exam

What You Need to Know

  • Passing score: 70% (at least 53 of 75 questions)
  • Exam length: 75 questions
  • Time limit: 1.5 hours (90 minutes)
  • Exam fee: $120 (non-refundable)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

NRSB RMT Study Tips from Top Performers

1Memorize the placement numbers cold: lowest lived-in level, at least 20 inches above the floor, 3 feet from exterior doors and windows, 1 foot from exterior walls, 4 inches from other objects and between duplicate detectors — placement questions are the exam's largest block (19 of 75).
2Know the closed-building rules: conditions start at least 12 hours before any test shorter than 4 days; windows stay closed, whole-house fans stay off, and window AC units run on recirculate only.
3Drill the units and conversions: 1 pCi/L = 37 Bq/m3, 4 pCi/L = 0.02 WL at the 50% equilibrium ratio, 1 WLM = 1 WL for 170 hours, and radon-222's 3.8-day half-life.
4Keep the three QA tools straight: duplicates (~10%) measure precision, field blanks (~5%) catch contamination, and spikes (~3 per 100) verify accuracy against a known chamber concentration.
5Learn the EPA follow-up logic from the Citizen's Guide: an initial result of 4 pCi/L or more triggers a follow-up test, results more than twice the action level call for an immediate second short-term test, and homes are fixed when the average is 4 pCi/L or higher.
6Download the free NRSB Certification Exams Study Guide from nrsb.org and review the 12 listed source documents — especially the EPA home measurement protocols and current ANSI/AARST standards.

Frequently Asked Questions

How many questions are on the NRSB RMT exam and what score do I need to pass?

The RMT exam has 75 single-best-answer multiple-choice questions with a 1.5-hour time limit. You must score 70% or higher — at least 53 of 75 questions correct. A preliminary score is emailed at completion, with the final score following within 72 hours after audit review.

What are the prerequisites for taking the NRSB RMT exam?

You must complete eight hours of NRSB-approved classroom training covering the nature of radon, radon entry into buildings, health risks, occupational health and safety, measurement devices and techniques, and current radon protocols. After passing the exam, certification also requires adherence to the NRSB code of ethics.

How is the NRSB RMT exam administered?

It is a virtual live-proctored digital exam taken on a desktop or laptop computer only — mobile devices and most work computers are not permitted. You may use one piece of scrap paper plus on-screen tools (notepad, formula sheet, calculator). The $120 exam fee is non-refundable, and you cannot reschedule within 24 hours of your appointment.

What can an NRSB-certified Radon Measurement Technician legally do?

An RMT is qualified to place and retrieve radon measurement devices to collect radon data. This work must be performed in accordance with an active quality assurance program and under the supervision of an NRSB-certified Radon Measurement Specialist (RMS) or an NRSB Accredited Radon Laboratory (ARL). Independent measurement services require the higher RMS credential.

What happens if I fail the RMT exam?

You must wait 14 days before retesting and pay the $120 fee again, as all exam fees are non-refundable. When you pass, the result remains valid for one year toward NRSB certification.

What topics dominate the RMT exam?

Test placement and conditions is the largest section (19 of 75 questions): device placement distances, closed-building conditions, interference, real estate protocols, and result interpretation. Basic concepts, health effects, test methods, and client relations carry 9 questions each, with smaller sections on mitigation, laboratory QA, government roles, and ethics.

How do I keep the RMT certification current?

NRSB certification costs $125 per year (or $200 for two years) and requires 4 approved continuing education credits annually. Technicians certified with NRSB for 10 or more years may renew with 2 CE credits for one year or 4 CE credits for two years.