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RADON EXAM QUESTIONS AND ANSWERS
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RADON EXAM QUESTIONS AND ANSWERS
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RADON EXAM QUESTIONS AND ANSWERSAccording to the US EPA Citizens Guide to Radon, radon levels in most homes, can be
reduced to: - Answers -2 pCi/L or less
Homeowners should be advised to have their mitigation contractors stipulate that they
will follow: - Answers -Radon Mitigation Standards such as the US EPA, AARST,
ASTM, or as recognized by their state radon office
Prolonged exposure to radon is considered dangerous because radon can cause: -
Answers -lung cancer
The most common radon mitigation technique at this time is: - Answers -Active soil
depressurization
The Radon Action Level in the United States is: - Answers -4.0 pico Curies per liter of
air
The submembrane mitigation strategy is applicable to which of the following foundation
types? - Answers -Crawl space houses
What is radon? - Answers -An invisible, odorless, tasteless, naturally occurring,
radioactive gas.
What is the minimum deployment/sampling period for a short-term test? - Answers -Two
days
What is the purpose of the US EPA Map of Radon Zones? - Answers -To suggest
where radon resistant new construction techniques would be the most cost-effectively
employed.
Which of the following best represents the recommendation of the U.S. EPA for citizen
exposure to radon? - Answers -Long-term exposure to elevated radon can increase the
potential for lung cancer
Which of the following is an acceptable location for the discharge of an active soil
depressurization system? - Answers -Above the eave of the roof.
Which of the following locations is appropriate for the fan of an active soil
depressurization system? - Answers -Attic
Which of the following Radon measurement approaches best estimates occupant
exposure? - Answers -A yearlong test with an alpha track detector in the lowest
occupied level of the home with no special precautions for closed building conditions.
,A correct statement regarding radon testing in Zone 3 areas of the EPA Radon Potential
Map is that such testing: - Answers -is recommended.
A significant difference between one room and the next in a building with a large central
air handling system is often caused by: - Answers -An unbalanced air distribution
system
The water supply to a home has been determined to be 9,500 pCi per liter of water. A
radon in air test was also conducted while it was occupied with a result of 22 pCi/L of
radon in the air. What is the predominant source of radon? - Answers -From the soil
What is one of the main differences between testing for radon in schools versus testing
in single family homes? - Answers -More robust forced air systems can cause
significant differences from one room to another in a school
What is the neutral pressure plane within a home? - Answers -It is the general location
within the home, above which the house is at positive pressure relative to the outdoors
and below which the house is at negative pressure relative to the outdoors.
What is the typical effect that the addition of outdoor air has on indoor radon levels? -
Answers -It typically reduces indoor radon
When is fresh air typically provided to large buildings such as schools? - Answers -
During occupied hours
Which of the following mechanical ventilation systems or conditions would most likely
reduce radon entry? - Answers -Evaporative cooler
Which of the following situations is caused by wind blowing on a home built on a
hillside? - Answers -Soil pressurization and increased radon entry.
Which of the following variables is the best predictor of potential radon concentrations in
buildings? - Answers -Radium content in the soil.
Short-term tests conducted in the same location with the house being under closed
building conditions will not vary more than 10 percent when tests are conducted at
different times of the year. - Answers -False
A curie is defined as: - Answers -the radioactivity of one gram of radium.
A house was tested for radon and radon decay progeny. The results were 10 pCi/L and
0.08 WL. What would most likely account for these measurements? - Answers -The
ventilation rate is very low and has high particulate count in air.
ER = WL X 100 / Rn
ER = 0.08 X
, ER = 8/10 = 0.8 or 80%
This is higher than the typically assumed 50%, which means there are more decay
products in the air than is typical. This would be caused by stagnant air or lots of
particulates in the air.
A measurement of 2 WL is made in a home. Using typical equilibrium ratio assumptions,
the radon concentration is: - Answers -400 pCi/L
A measurement of 4 pCi/L is made in a home. Using typical equilibrium ratio
assumptions, the working level is: - Answers -0.02 WL
Use the equilibrium equation to solve for radon decay products in units of working levels
(WL). Assume 50% ER since no additional information was provided.
WL = ER X Rn / 100
WL = .5 X
WL =
WL = 0.02 WL
A radioactive element, which has a half-life of 30 days, was collected in a sealed
container. If on January 1 it was determined that the container held 100 grams of this
specific element, how much of this same specific material would be in the container as
of June 1 of the same year? - Answers -3.13 grams
Be careful and make sure you determine the number of half life intervals. You might
assume January to June is 6 months -- and since the half life is a month -- 6 half lives
have transpired. But it is only 5 months since stopped on June 1 rather than June 30.
Jan 1 - 100 grams
Feb 1 - 50 grams
Mar 1 - 25 grams
Apr 1 - 12.5 grams
May 1 - 6.25 grams
Jun 1 - 3.13 grams
An equilibrium ratio of 50 percent is typically assumed in residential buildings. What
does this mean? - Answers -Of the radon decay products that were produced from the
radon in the room, only half of them are floating around in the air space and available
for breathing or measurement.
An ion is: - Answers -An atom that has either gained or lost an electron
Assuming an equilibrium ratio of 0.5 (50%), 4 pCi/L equates to how many working
levels? - Answers -0.2
Using the pie chart described within the course, we can solve for radon decay products
or WL if we assume an equilibrium factor. When assuming, we will use 50%.
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