Radon Testing: Teacher Answer Key
Name:	Date:
Home A:
Home B:
Winter reading
Summer reading
3.5 pCi/L
1.0 pCi/L
Average radon level:
3.5 + 1 = 4.5/2 = 2.25 pCi/L
Does this home's radon level need to be fixed? Explain your
answer.
Answers may vary. This homeowner may want to consider
lowering the indoor radon level, especially since the reading was
higher during the winter.
Reading during rainy
season
Reading during dry,
windy weather
5.0 pCi/L
10.0 pCi/L
Average radon level:
5 + 10 = 15/2 = 7.5 pCi/L
Does this home's radon level need to be fixed? Explain your
answer.
This homeowner should definitely consider lowering the indoor
radon level. It is well above EPA's action level of 4 pCi/L or
higher.
When testing your home for radon, why is it important to get a year-round average radon level?
Radon levels tend to vary from day to day and season to season. For example, rainfall may slow
radon's movement through soil so that less gets into the home. In dry periods radon has an easier
time moving to the surface through cracks and crevices. Weather extremes when homes are
closed and heat and air conditioning are turned on, or windy weather may lead to a lower
pressure in the home which creates a vacuum and draws radon in from a higher pressure area in
All fcJL United States	RadTown Radon Activity Set	EPA 402-B-19-059
npMjl Environmental Protection	,
#* Agency	https://www.EPA.gov/RadTown/Activity-3-lndoor-Radon-Levels

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