VIRGINIA RADON MEASUREMENT TECHNICIAN
CERTIFICATION EXAM — 200 EXAM QUESTIONS WITH
VERIFIED ANSWERS & RATIONALES
1. What is radon?
A. A combustible hydrocarbon gas
B. A naturally occurring radioactive gas
C. A synthetic refrigerant gas
D. A harmless atmospheric oxygen compound
Answer: B
Rationale: Radon is a naturally occurring, colorless, odorless, radioactive
gas produced by the radioactive decay of uranium in soil, rock, and
sometimes groundwater. Because it cannot be detected by human
senses, measurement is necessary to determine whether an indoor
radon problem exists.
2. In what unit is indoor radon concentration commonly reported?
A. Milligrams per cubic meter
B. Becquerels per gram
C. Picocuries per liter
D. Roentgens per hour
Answer: C
Rationale: Indoor radon concentration is commonly expressed in
picocuries per liter (pCi/L). A radon measurement report should identify
,the concentration using the appropriate unit so that the result can be
properly interpreted.
3. What is the EPA recommended action level for radon in indoor air?
A. 0.4 pCi/L
B. 2.0 pCi/L
C. 4.0 pCi/L
D. 10.0 pCi/L
Answer: C
Rationale: The EPA recommends that homes be fixed if the radon level
is 4 picocuries per liter (pCi/L) or more. The EPA also recommends that
Americans consider fixing their home for radon levels between 2 pCi/L
and 4 pCi/L.
4. Which of the following best describes the half-life of radon-222?
A. 3.8 days
B. 22 years
C. 1600 years
D. 12 hours
Answer: A
Rationale: Radon-222 has a half-life of approximately 3.8 days. This
relatively short half-life is important for understanding the decay chain
and the time it takes for radon concentrations to reach equilibrium.
5. What is the primary health risk associated with long-term radon
exposure?
A. Skin cancer
B. Lung cancer
C. Leukemia
D. Thyroid disease
,Answer: B
Rationale: The primary health risk associated with radon exposure is an
increased risk of lung cancer. Radon decay products can adhere to dust
particles and lung tissue, where alpha radiation damages lung tissue.
Radon is considered the second leading cause of lung cancer after
cigarette smoking.
6. Radon is produced from the radioactive decay of which element?
A. Carbon
B. Uranium
C. Potassium
D. Thorium
Answer: B
Rationale: Radon is produced by the radioactive decay of uranium in
soil, rock, and water. The decay chain proceeds from uranium to radium
to radon gas, which can then migrate into buildings.
7. What is the primary source of radon in indoor air?
A. Building materials
B. Groundwater
C. Soil gas
D. Outdoor air
Answer: C
Rationale: Soil gas is the primary source of radon in indoor air. Radon
enters buildings through cracks, openings, and other penetrations in the
foundation. While building materials and water can contribute, soil gas
is the dominant source.
8. Which of the following is NOT a common radon entry route into a
building?
, A. Cracks in concrete slabs
B. Gaps around pipes and wires
C. Open windows
D. Sump pumps and drains
Answer: C
Rationale: Open windows typically dilute indoor radon concentrations
rather than serve as an entry route. Common radon entry routes
include cracks in concrete slabs, gaps around pipes and wires, sump
pumps, drains, and other penetrations in the foundation.
9. What does the term "working level" (WL) refer to?
A. A measure of radon gas concentration
B. A measure of radon decay product concentration
C. A measure of radiation dose to workers
D. A measure of soil permeability
Answer: B
Rationale: Working Level (WL) is a measure of the concentration of
radon decay products (also called radon progeny) in air. One WL is
defined as the concentration of short-lived radon decay products that
will result in the emission of 1.3 × 10⁵ MeV of alpha energy per liter of
air.
10. What is the relationship between pCi/L and Working Level (WL)?
A. 1 pCi/L is approximately equal to 1 WL
B. 4 pCi/L is approximately equal to 0.02 WL
C. 1 pCi/L is approximately equal to 100 WL
D. 10 pCi/L is approximately equal to 1 WL
Answer: B
Rationale: As a general guide, 4 picocuries per liter is approximately
CERTIFICATION EXAM — 200 EXAM QUESTIONS WITH
VERIFIED ANSWERS & RATIONALES
1. What is radon?
A. A combustible hydrocarbon gas
B. A naturally occurring radioactive gas
C. A synthetic refrigerant gas
D. A harmless atmospheric oxygen compound
Answer: B
Rationale: Radon is a naturally occurring, colorless, odorless, radioactive
gas produced by the radioactive decay of uranium in soil, rock, and
sometimes groundwater. Because it cannot be detected by human
senses, measurement is necessary to determine whether an indoor
radon problem exists.
2. In what unit is indoor radon concentration commonly reported?
A. Milligrams per cubic meter
B. Becquerels per gram
C. Picocuries per liter
D. Roentgens per hour
Answer: C
Rationale: Indoor radon concentration is commonly expressed in
picocuries per liter (pCi/L). A radon measurement report should identify
,the concentration using the appropriate unit so that the result can be
properly interpreted.
3. What is the EPA recommended action level for radon in indoor air?
A. 0.4 pCi/L
B. 2.0 pCi/L
C. 4.0 pCi/L
D. 10.0 pCi/L
Answer: C
Rationale: The EPA recommends that homes be fixed if the radon level
is 4 picocuries per liter (pCi/L) or more. The EPA also recommends that
Americans consider fixing their home for radon levels between 2 pCi/L
and 4 pCi/L.
4. Which of the following best describes the half-life of radon-222?
A. 3.8 days
B. 22 years
C. 1600 years
D. 12 hours
Answer: A
Rationale: Radon-222 has a half-life of approximately 3.8 days. This
relatively short half-life is important for understanding the decay chain
and the time it takes for radon concentrations to reach equilibrium.
5. What is the primary health risk associated with long-term radon
exposure?
A. Skin cancer
B. Lung cancer
C. Leukemia
D. Thyroid disease
,Answer: B
Rationale: The primary health risk associated with radon exposure is an
increased risk of lung cancer. Radon decay products can adhere to dust
particles and lung tissue, where alpha radiation damages lung tissue.
Radon is considered the second leading cause of lung cancer after
cigarette smoking.
6. Radon is produced from the radioactive decay of which element?
A. Carbon
B. Uranium
C. Potassium
D. Thorium
Answer: B
Rationale: Radon is produced by the radioactive decay of uranium in
soil, rock, and water. The decay chain proceeds from uranium to radium
to radon gas, which can then migrate into buildings.
7. What is the primary source of radon in indoor air?
A. Building materials
B. Groundwater
C. Soil gas
D. Outdoor air
Answer: C
Rationale: Soil gas is the primary source of radon in indoor air. Radon
enters buildings through cracks, openings, and other penetrations in the
foundation. While building materials and water can contribute, soil gas
is the dominant source.
8. Which of the following is NOT a common radon entry route into a
building?
, A. Cracks in concrete slabs
B. Gaps around pipes and wires
C. Open windows
D. Sump pumps and drains
Answer: C
Rationale: Open windows typically dilute indoor radon concentrations
rather than serve as an entry route. Common radon entry routes
include cracks in concrete slabs, gaps around pipes and wires, sump
pumps, drains, and other penetrations in the foundation.
9. What does the term "working level" (WL) refer to?
A. A measure of radon gas concentration
B. A measure of radon decay product concentration
C. A measure of radiation dose to workers
D. A measure of soil permeability
Answer: B
Rationale: Working Level (WL) is a measure of the concentration of
radon decay products (also called radon progeny) in air. One WL is
defined as the concentration of short-lived radon decay products that
will result in the emission of 1.3 × 10⁵ MeV of alpha energy per liter of
air.
10. What is the relationship between pCi/L and Working Level (WL)?
A. 1 pCi/L is approximately equal to 1 WL
B. 4 pCi/L is approximately equal to 0.02 WL
C. 1 pCi/L is approximately equal to 100 WL
D. 10 pCi/L is approximately equal to 1 WL
Answer: B
Rationale: As a general guide, 4 picocuries per liter is approximately
