Government of Canada Radon Guideline
Health Canada collaborated with the Federal
Provincial Territorial Radiation Protection Committee (FPTRPC) to review the
health risk from exposure to radon. The risk
assessment is based on new scientific information and was the
subject of broad public
consultation. Using the risk assessment and feedback obtained
from the public consultation, the Government of Canada is updating
its guideline for exposure to radon in indoor air. This updated
guideline provides advice that is more broadly applicable and more
protective than the previous FPTRPC guideline.
The Minister recommends that
- Remedial measures should be undertaken in a dwelling whenever
the average annual radon concentration exceeds 200 Bq/m3 in the normal occupancy area.
- The higher the radon concentration, the sooner remedial
measures should be undertaken.
- When remedial action is taken, the radon level should be
reduced to a value as low as practicable.
- The construction of new dwellings should employ techniques
that will minimize radon entry and will facilitate
post-construction radon removal, should this subsequently prove
necessary.
Further, Health Canada will consult with stakeholders and the public on
the need for a target for new construction. The proposed addition to
the guideline would recommend that builders employ techniques to
achieve a radon concentration less than 100 Bq/m3 in the
normal occupancy area and facilitate post-construction radon
removal, should this prove to be necessary.
Comments on the proposed target for new construction can be sent
to radon@hc-sc.gc.ca or by
mail at Radon, Radiation Protection Bureau, Health Canada, 775 Brookfield Road, Ottawa, Ontario, K1A 1C1. The period for submission of comments will close on August 9, 2007.
Points of clarification
- In addition to residential homes, the term "dwelling" in this
guideline also applies to public buildings with a high occupancy
rate by members of the public such as schools, hospitals,
long-term care residences, and correctional facilities. The
following settings are excluded from this guideline:
- Uranium mines, which are regulated by the Canadian Nuclear Safety Commission;
- Other mines (e.g., fluorspar mines), which are
regulated by provincial mining authorities; and
- Other workplaces which would be addressed by existing
guidelines for naturally occurring radioactive materials (NORM).
Details are given in the Canadian Guidelines for Management of
Naturally Occurring Radioactive Materials (NORM) and a copy may
be viewed or downloaded.
- The "normal occupancy area" refers to any part of the dwelling
where a person is likely to spend several hours (greater than four)
per day. This would include a finished basement with a family
room, guest room, office or work shop. It would also include a
basement apartment. It would exclude an unfinished basement, a
crawl space, or any area that is normally closed off and accessed
infrequently, e.g., a storage area, cold room, furnace room, or
laundry room.
- The aim is to remediate and reduce the radon concentration to
less than 200 Bq/m3. If the radon concentration is
found to be greater than 600 Bq/m3, the remedial
actions are recommended to be completed in less than a year;
between 200 Bq/m3 and 600 Bq/m3, the
remedial actions should be completed in less than two years.
- "As low as practicable" refers to what can be achieved with
conventional radon reduction methods in a cost-effective manner.
This is consistent with the ALARA (As Low As Reasonably
Achievable) principle, whereby reasonable efforts are made to
maintain radiation exposures as low as possible, with social and
economic factors taken into consideration. In most situations, a
final level less than 200 Bq/m3 will be readily
achievable. In a small number of cases, it may happen that the
application of all reasonable remediation techniques will still
leave a residual radon level greater than 200 Bq/m3.
It is not the intention of this guideline to recommend excessive
or unreasonable remediation costs in order to achieve a marginal
increase in benefit. Such situations should be evaluated on a
case-by-case basis.
- This Government of Canada guideline is based on the guidance
approved by the FPTRPC. The guideline is based upon current
scientific understanding. It will be reviewed and updated as
appropriate. Further information on radon may be obtained from the appropriate federal, provincial or territorial contact.
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