NRPP Radon Measurements
Q: If a sample of radon is taken from a room that is known to be at 125 pCi/L and is kept in a
well-sealed container, what will the approximate radon activity be within the container after
eight days?
CORRECT ANSWER: 31.3 pCi/L
Q: Radon decay products have (longer or shorter) half-lives than radon gas?
CORRECT ANSWER: Shorter
Q: The ionization of an otherwise electrically neutral atom is used in measuring radiation. Which
process best describes ionization?
CORRECT ANSWER: An uncharged atom gains or loses orbital electrons and
becomes electrically charged.
Q: Give three characteristics of radon.
CORRECT ANSWER:
• Half-life of 3.8 days
• Inert
• Can't sense (see, smell, or taste)
• Radioactive
• Naturally occurring
• Gas
Q: If a room within a home is determined to be at 25 pCi/L, what working level would be
expected in this room using typical assumptions for equilibrium ratio in residential buildings?
CORRECT ANSWER: 0.13 WL
Q: What is the highest working level that could be observed in a room having a constant radon
activity of 10 pCi/L?
CORRECT ANSWER: 0.1 WL
,Q: If a radon measurement is calculated to be 7.8456 pCi/L, what number should be written on
the report to the client?
CORRECT ANSWER: 7.8 pCi/L
Q: A building has a very high internal air circulation rate and was measured at 0.03 WL. What
can be said about the radon concentrations?
CORRECT ANSWER: The radon is probably more than 6 pCi/L.
Q: What is the approximate outdoor radon concentration?
CORRECT ANSWER: 0.4 pCi/L
Q: Within the U.S., the EPA believes the average annual indoor radon activity to be:
CORRECT ANSWER: 1.3 pCi/L
Q: What would be the expected working levels in a room at 4 pCi/L, using typical assumptions
for equilibrium ratio in residential buildings?
CORRECT ANSWER: 0.02 WL
Q: In order to calculate the equilibrium ratio in a home you need to know:
CORRECT ANSWER: Results of simultaneous measurements of radon and radon
decay products.
Q: Lung cancer risks exist with exposures to radon concentrations below 4 pCi/L.
CORRECT ANSWER: True
Q: Short-term measurements can be factored by the time of deployment to determine a year-long
average.
CORRECT ANSWER: False
, Q: The results of a short-term, closed building test indicate the highest the radon could ever be.
CORRECT ANSWER: False
Q: Radon is only a concern in homes, not in schools and workplaces.
CORRECT ANSWER: False
Q: When emitted within the lungs, which one of the three ionizing radiation types causes the
most cell damage within the lung?
CORRECT ANSWER: Alpha particle
Q: The health risk of radon has most strongly been determined by what studies?
CORRECT ANSWER: Occupational exposures and lung cancer incidence in
underground miners (Miner Studies)
Q: According to the most recent version of U.S. EPA's Home Buyer's and Seller's Guide, what is
the estimated number of cancer deaths that occur annually in the United States from radon
exposure in homes?
CORRECT ANSWER: 15,000 – 22,000
Q: Referring to the most recent health risk chart from the U.S. EPA's Citizen's Guide, who
would have the greater lifetime risk of contracting radon-induced lung cancer?
• A smoker in a home at 4 pCi/L
• A former smoker at 10 pCi/L
• A never smoker at 20 pCi/L
• A never smoker at 100 pCi/L
CORRECT ANSWER: A never smoker at 100 pCi/L
Q: According to EPA's linear, no-threshold health risk model, which set of circumstances would
present the highest health risk from radon (assume all things equal)?
• 100 pCi/L for 1 year
• 30 pCi/L for 8 years
Q: If a sample of radon is taken from a room that is known to be at 125 pCi/L and is kept in a
well-sealed container, what will the approximate radon activity be within the container after
eight days?
CORRECT ANSWER: 31.3 pCi/L
Q: Radon decay products have (longer or shorter) half-lives than radon gas?
CORRECT ANSWER: Shorter
Q: The ionization of an otherwise electrically neutral atom is used in measuring radiation. Which
process best describes ionization?
CORRECT ANSWER: An uncharged atom gains or loses orbital electrons and
becomes electrically charged.
Q: Give three characteristics of radon.
CORRECT ANSWER:
• Half-life of 3.8 days
• Inert
• Can't sense (see, smell, or taste)
• Radioactive
• Naturally occurring
• Gas
Q: If a room within a home is determined to be at 25 pCi/L, what working level would be
expected in this room using typical assumptions for equilibrium ratio in residential buildings?
CORRECT ANSWER: 0.13 WL
Q: What is the highest working level that could be observed in a room having a constant radon
activity of 10 pCi/L?
CORRECT ANSWER: 0.1 WL
,Q: If a radon measurement is calculated to be 7.8456 pCi/L, what number should be written on
the report to the client?
CORRECT ANSWER: 7.8 pCi/L
Q: A building has a very high internal air circulation rate and was measured at 0.03 WL. What
can be said about the radon concentrations?
CORRECT ANSWER: The radon is probably more than 6 pCi/L.
Q: What is the approximate outdoor radon concentration?
CORRECT ANSWER: 0.4 pCi/L
Q: Within the U.S., the EPA believes the average annual indoor radon activity to be:
CORRECT ANSWER: 1.3 pCi/L
Q: What would be the expected working levels in a room at 4 pCi/L, using typical assumptions
for equilibrium ratio in residential buildings?
CORRECT ANSWER: 0.02 WL
Q: In order to calculate the equilibrium ratio in a home you need to know:
CORRECT ANSWER: Results of simultaneous measurements of radon and radon
decay products.
Q: Lung cancer risks exist with exposures to radon concentrations below 4 pCi/L.
CORRECT ANSWER: True
Q: Short-term measurements can be factored by the time of deployment to determine a year-long
average.
CORRECT ANSWER: False
, Q: The results of a short-term, closed building test indicate the highest the radon could ever be.
CORRECT ANSWER: False
Q: Radon is only a concern in homes, not in schools and workplaces.
CORRECT ANSWER: False
Q: When emitted within the lungs, which one of the three ionizing radiation types causes the
most cell damage within the lung?
CORRECT ANSWER: Alpha particle
Q: The health risk of radon has most strongly been determined by what studies?
CORRECT ANSWER: Occupational exposures and lung cancer incidence in
underground miners (Miner Studies)
Q: According to the most recent version of U.S. EPA's Home Buyer's and Seller's Guide, what is
the estimated number of cancer deaths that occur annually in the United States from radon
exposure in homes?
CORRECT ANSWER: 15,000 – 22,000
Q: Referring to the most recent health risk chart from the U.S. EPA's Citizen's Guide, who
would have the greater lifetime risk of contracting radon-induced lung cancer?
• A smoker in a home at 4 pCi/L
• A former smoker at 10 pCi/L
• A never smoker at 20 pCi/L
• A never smoker at 100 pCi/L
CORRECT ANSWER: A never smoker at 100 pCi/L
Q: According to EPA's linear, no-threshold health risk model, which set of circumstances would
present the highest health risk from radon (assume all things equal)?
• 100 pCi/L for 1 year
• 30 pCi/L for 8 years
