Minnesota Radon Mitigation Contractor
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary health risk associated with long-term radon
exposure?
A) Lung cancer
B) Skin cancer
C) Asthma
D) Liver disease
Correct Answer: A) Lung cancer
Rationale: Radon decay products release alpha particles that damage
lung tissue, significantly increasing lung cancer risk over time.
2. Radon is classified as which type of gas?
A) Synthetic industrial gas
B) Naturally occurring radioactive gas
, C) Combustible fossil gas
D) Greenhouse inert gas
Correct Answer: B) Naturally occurring radioactive gas
Rationale: Radon is produced from the natural decay of uranium in
soil, rock, and groundwater.
3. The most common radon mitigation method in residential homes is:
A) Sealing all windows
B) Sub-slab depressurization
C) Installing air conditioning
D) Painting basement walls
Correct Answer: B) Sub-slab depressurization
Rationale: This system reduces radon entry by drawing soil gas from
beneath the slab and venting it outside.
4. Radon gas typically enters buildings through:
A) Roof vents
B) Electrical outlets only
C) Foundation cracks and openings
D) HVAC filters
Correct Answer: C) Foundation cracks and openings
Rationale: Radon moves from soil into buildings through the path of
least resistance such as cracks and joints.
,5. The unit of radon measurement is:
A) ppm
B) mSv
C) pCi/L
D) dB
Correct Answer: C) pCi/L
Rationale: Picocuries per liter (pCi/L) is the standard unit used to
measure radon concentration in air.
6. EPA action level for radon in homes is:
A) 1.0 pCi/L
B) 2.0 pCi/L
C) 4.0 pCi/L
D) 10.0 pCi/L
Correct Answer: C) 4.0 pCi/L
Rationale: EPA recommends mitigation at or above 4.0 pCi/L to
reduce health risk.
7. A manometer in a radon system is used to:
A) Measure airflow temperature
B) Measure pressure differential
C) Measure humidity
D) Detect radon directly
Correct Answer: B) Measure pressure differential
, Rationale: It indicates whether the mitigation system is creating
adequate suction under the slab.
8. Active soil depressurization requires:
A) Passive vent only
B) A fan
C) Gravel only
D) Sealant only
Correct Answer: B) A fan
Rationale: An inline radon fan actively draws soil gas from beneath
the building.
9. Passive radon systems become active when:
A) A filter is added
B) A fan is installed later
C) Windows are opened
D) Soil is compacted
Correct Answer: B) A fan is installed later
Rationale: Passive systems are designed for future conversion to
active mitigation by adding a fan.
10. Radon mitigation fans are typically installed:
A) Inside living spaces
B) In attics or outside
C) Under carpets
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary health risk associated with long-term radon
exposure?
A) Lung cancer
B) Skin cancer
C) Asthma
D) Liver disease
Correct Answer: A) Lung cancer
Rationale: Radon decay products release alpha particles that damage
lung tissue, significantly increasing lung cancer risk over time.
2. Radon is classified as which type of gas?
A) Synthetic industrial gas
B) Naturally occurring radioactive gas
, C) Combustible fossil gas
D) Greenhouse inert gas
Correct Answer: B) Naturally occurring radioactive gas
Rationale: Radon is produced from the natural decay of uranium in
soil, rock, and groundwater.
3. The most common radon mitigation method in residential homes is:
A) Sealing all windows
B) Sub-slab depressurization
C) Installing air conditioning
D) Painting basement walls
Correct Answer: B) Sub-slab depressurization
Rationale: This system reduces radon entry by drawing soil gas from
beneath the slab and venting it outside.
4. Radon gas typically enters buildings through:
A) Roof vents
B) Electrical outlets only
C) Foundation cracks and openings
D) HVAC filters
Correct Answer: C) Foundation cracks and openings
Rationale: Radon moves from soil into buildings through the path of
least resistance such as cracks and joints.
,5. The unit of radon measurement is:
A) ppm
B) mSv
C) pCi/L
D) dB
Correct Answer: C) pCi/L
Rationale: Picocuries per liter (pCi/L) is the standard unit used to
measure radon concentration in air.
6. EPA action level for radon in homes is:
A) 1.0 pCi/L
B) 2.0 pCi/L
C) 4.0 pCi/L
D) 10.0 pCi/L
Correct Answer: C) 4.0 pCi/L
Rationale: EPA recommends mitigation at or above 4.0 pCi/L to
reduce health risk.
7. A manometer in a radon system is used to:
A) Measure airflow temperature
B) Measure pressure differential
C) Measure humidity
D) Detect radon directly
Correct Answer: B) Measure pressure differential
, Rationale: It indicates whether the mitigation system is creating
adequate suction under the slab.
8. Active soil depressurization requires:
A) Passive vent only
B) A fan
C) Gravel only
D) Sealant only
Correct Answer: B) A fan
Rationale: An inline radon fan actively draws soil gas from beneath
the building.
9. Passive radon systems become active when:
A) A filter is added
B) A fan is installed later
C) Windows are opened
D) Soil is compacted
Correct Answer: B) A fan is installed later
Rationale: Passive systems are designed for future conversion to
active mitigation by adding a fan.
10. Radon mitigation fans are typically installed:
A) Inside living spaces
B) In attics or outside
C) Under carpets
