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Radon Fact Sheet
The Issue
From time to time the City of Edmonton
receives inquiries from citizens who are
concerned about radon levels in their homes.
This fact sheet provides background
information about radon and the results of the Measuring Radon Levels
City of Edmonton residential radon study Health Canada studies show that radon is not
(overleaf). The results of the study showed widespread in Canadian homes. However,
that typical radon levels in Edmonton the only way to know the radon level is to test
households are low. your home. If you are concerned about
exposure to radon gas, commercial services
What is radon? are available for homeowners who wish to
Radon a colorless, odorless radioactive gas measure radon levels in their homes. A
that occurs naturally in the environment. popular home radon monitor uses a small
Naturally occurring radon comes from the pump to force air through a filter that traps
breakdown of uranium, which is common in radon progeny. The detector is returned to the
natural geologic materials such as granite, laboratory for analysis.
shale, or phosphate minerals.
When should you take action?
The Health Effects of Radon Health Canada has established a remedial
Radon gas decays, producing radiation and action guideline for radon gas concentrations
radioactive atoms called “radon progeny”, or of 800 Bq/m3 or about 110 mWL.
“radon daughters”. These progeny decay
rapidly themselves. The decay of radon and Current action levels in other countries are
progeny produces alpha radiation, which can much lower than in Canada. In 2007, it is
damage soft tissue. expected that Health Canada will reduce the
radon guideline from 800 Bq/m3 to 200
Inhalation of radon is the main route of entry Bq/m3 (from 110 mWL to 26 mWL), to bring
into the body. Exposure to high levels has the Canadian guidelines more into line with
been associated with increased risk of lung guidelines established by international
cancer, depending on the length of time you authorities.
are exposed to it.
Definitions:
Radon in the Home A bequerel (Bq) is a measurement of the rate
Radon gas may seep into a home through of decay: one disintegration per second. A
cracks in the foundation walls and floor, Working Level (WL) is a measure of the
through unsealed openings around drain energy produced by radon progeny. A mWL
pipes and sump pumps, or though other is a milli Working Level (1/1000th of a WL).
unsealed openings. Radon easily dissolves The ratio between radon gas and its radon
into water, and dissolved radon may be progeny varies with a number of factors, but
present where high background uranium in most houses, 0.025 WL is approximately
exists. Radon will escape from water when equivalent to 200 Bq/m3 of radon.
exposed to the atmosphere, especially if it is
stirred, agitated or the pressure is lowered.
City of Edmonton
Residential Radon Study
Radon levels were measured in ten
Edmonton and area residences in 2007.
The sample locations are presented on the
map (right) and the results are presented in
the table (below).
A radon monitor was placed in the basement
of each home in a frequented area, away
from furnace rooms, laundries and crawl
spaces. The monitors were plugged in and
allowed to run continuously for seven days.
After seven days, the monitors were
returned to the Radiation Safety Institute of
Canada laboratory for analysis.
Sample Radon Progeny
Neighborhood
# (mWL)
1 Kilkenny 9
2 Menisa (Millwoods) 2
3 Baranow 4
4 Fraser 3
The measured radon and progeny levels in
5 Parkallen 3
Edmonton basements were between
6 Holyrood 8
2 and 9 mWL, well below international guidelines for
7 Keheewin 2
remedial action.
8 Meadowlark 2
9 St. Albert 6 According to the CMHC (2007) typical radon level in
10 Terwillegar 4 most Canadian homes ranges between 30 and 100
Remedial Action Guidelines: Bq/m3 (between 4 and 12 mWL).
Canada (current) 110 Typical homes in Edmonton have low, naturally
Canada (proposed, 2007) 26 occurring radon levels. The range of radon and
World Health Organization & radon progeny levels measured in Edmonton
26
United Kingdom residences during this study is lower than the
United States 20 reported national background range.
mWL = milliWorking Level
For additional information, contact:
References: Don McClymont, P.Geol.
Environmental Hydrogeologist
Canada Mortgage and Housing Corporation, Engineering Services
Health Canada (2007). Radon: A Guide for City of Edmonton
Canadian Homeowners. (780) 496-6778
http://www.cmhc-schl.gc.ca/odpub/pdf/61945.pdf
Wanda Goulden, P.Eng., P.Geol.
Radiation Safety Institute of Canada, General Supervisor of Geoenvironmental Engineering
Saskatoon National Laboratories, Engineering Services
102 – 110 Research Drive, Saskatoon, SK. City of Edmonton
(780) 496-1089
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