RMS Radon Measurement Techniques 2 — Questions and Answers
Question 1: Which type of radon test device is considered a 'passive' measurement device?
- Continuous radon monitor
- Electret ion chamber (Correct answer)
- Lucas cell scintillation device
- Flow-through ionization chamber
Correct answer: Electret ion chamber
Electret ion chambers are passive devices that do not require power or active airflow to collect radon measurements.
Question 2: What is the minimum recommended test duration for a short-term radon test using charcoal canisters?
- 12 hours
- 24 hours (Correct answer)
- 48 hours
- 7 days
Correct answer: 24 hours
EPA guidelines require charcoal canister short-term tests to be deployed for a minimum of 48 hours, though 24 hours is the minimum for some charcoal liquid scintillation devices.
Question 3: A continuous radon monitor placed in a basement shows significantly higher readings at night than during the day. What is the most likely explanation?
- Device malfunction at lower temperatures
- Stack effect causing increased radon entry overnight (Correct answer)
- Interference from outdoor radon sources
- Battery voltage fluctuation affecting sensor accuracy
Correct answer: Stack effect causing increased radon entry overnight
The stack effect increases overnight when windows and doors are closed and temperature differentials drive soil gas (including radon) into the building.
Question 4: Which measurement protocol must be followed when conducting a post-mitigation test to ensure accurate results?
- Open-house conditions for at least 12 hours prior
- Closed-house conditions for at least 12 hours prior
- Closed-house conditions for at least 24 hours prior (Correct answer)
- Normal living conditions with no restrictions
Correct answer: Closed-house conditions for at least 24 hours prior
EPA protocols require closed-house conditions for at least 24 hours before and during a post-mitigation short-term test.
Question 5: An alpha track detector measures radon by recording:
- Gamma radiation emitted by radon decay products
- Alpha particle damage tracks on a sensitive film (Correct answer)
- Beta particles captured on an electrostatic collector
- Ion pairs produced in a pressurized gas chamber
Correct answer: Alpha particle damage tracks on a sensitive film
Alpha track detectors contain a special plastic film (LR-115 or CR-39) that retains microscopic damage tracks from alpha particles emitted during radon decay.
Question 6: What is the primary advantage of using a long-term radon test (90+ days) over a short-term test?
- Lower cost per test
- Results are available faster
- Better representation of annual average radon exposure (Correct answer)
- Approved for real estate transactions
Correct answer: Better representation of annual average radon exposure
Long-term tests average radon levels over seasons and varying conditions, providing a more accurate estimate of annual exposure than short-term snapshots.
Question 7: When testing a home with a crawl space, where should the measurement device be placed according to EPA protocol?
- Inside the crawl space at ground level
- In the lowest livable area of the home above the crawl space (Correct answer)
- At the entry door to the crawl space
- In the attic to capture whole-house average
Correct answer: In the lowest livable area of the home above the crawl space
EPA protocol places the measurement device in the lowest livable area of the home, not in the crawl space itself, since that is where occupants are exposed.
RMS Radon Measurement Techniques 2
Which type of radon test device is considered a 'passive' measurement device?