Below is a copy of the regulation proposed on December 13, 2006 by the Minister or the
Governor in Council under the Canadian Environmental Protection Act, 1999
is published by the Minister in Part I of the Canada Gazette, Canada's
official parliamentary journal.
DEPARTMENT OF HEALTH
CANADIAN ENVIRONMENTAL
PROTECTION ACT, 1999
Proposed residential indoor air quality guideline for moulds
Pursuant to subsection
55(3) of the Canadian Environmental Protection Act, 1999, the Minister of Health hereby gives notice of
a proposed residential indoor air quality guideline for moulds. After reviewing
the most recent scientific evidence regarding moulds and its effects on health,
the Minister recommends to control humidity and diligently repair any water
damage in residences to prevent mould growth; and
- to clean thoroughly any mould growing in residential
buildings.
These recommendations
apply regardless of the mould species found to be growing in the building.
Any person may, within
60 days after publication of this notice, file with the Minister of Health
written comments on the proposed guidelines. All written comments will be made
available upon request to all interested parties. All comments, requests for
copies of the proposal, and information requests must cite the Canada Gazette, Part I, and the date of publication of this
notice and be sent to the Air Health Effects Division, Health Canada, 269
Laurier Avenue W, 3rd Floor, PL 4903C, Ottawa, Ontario K1A 0K9, 613-957-1876
(telephone), 613-954-7612 (fax), air@hc-sc.gc.ca (email).
December 13, 2006
PAUL GLOVER
Director
General
Safe Environments Programme
On behalf of the Minister of Health
ANNEX
RESIDENTIAL INDOOR AIR QUALITY GUIDELINE
MOULDS
Physical and chemical
properties
The word
"mould" is a common term referring to fungi that can grow on building
materials in homes or other buildings. Mould growth can influence air quality
because both spores and mycelial fragments are dispersed into the air and can
be inhaled. Their penetration into the bronchial tree depends on their size.
The smaller particles penetrate deeper into the lungs.
Three features of mould
biochemistry are of special interest in terms of human health:
Mould cell walls contain (1->3)-ß-D-glucan, a
compound with inflammatory properties;
- Mould spores and mycelial fragments contain allergens;
and
- The spores of some species contain low molecular weight
chemicals that are cytotoxic or have other toxic properties (e.g.
satratoxins and atranones produced by Stachybotrys chartarum).
Causes of mould growth
Mould growth in a house
requires the presence of nutrients, an adequate temperature, and a sufficient
amount of water. The first two requirements being usually met in indoor
environments, fungal growth usually results from a moisture problem (CMHC
2003). Major causes of mould growth are:
- excess humidity resulting in condensation on surfaces;
- water leakage, e.g. from a broken pipe;
- infiltration of water from the outside, e.g. from a
leaking roof or a cracked basement; and
- a flood.
Health effects
Health Canada has
carried out two reviews of the scientific literature pertaining to the health
effects of indoor moulds (Health Canada 1995; 2004). The Institut national de
santé publique du Québec also published a review on this subject (d'Halewyn et
al. 2003). The following conclusions were drawn:
- Exposure to indoor mould is associated with an
increased prevalence of asthma-related symptoms such as chronic wheezing,
irritative, and non-specific symptoms; and
- In laboratory animal studies, instillation of fungal
antigens (Penicillium sp. and Aspergillus
sp.) and fungal cell components [(1->3)-ß-D-glucan] resulted in an
inflammatory response in the lungs of rodents, while instillation of Stachbotrys chartarum spores resulted in severe biochemical and
ultrastructural changes.
These conclusions have
been supported by more recent findings. In two cohort studies (Wickman et al.
2003; Jaakkola et al. 2005), significant associations were found between home
dampness and the risk of developing asthma. In experimental studies, asthma-like
responses were observed in mice following exposure to a typical
building-associated fungus, Penicillium chrysogenum (Chung et al. 2005), and inflammatory responses were seen in rats
exposed to low doses of toxins from the same species (Rand et al. 2005).
Residential Indoor Air
Quality Guideline
Health Canada considers
that mould growth in residential buildings may pose a health hazard. Health
risks depend on exposure and, for asthma symptoms, on allergic sensitization.
Therefore, Health Canada recommends
- to control humidity and diligently repair any water
damage in residences to prevent mould growth; and
- to clean thoroughly any mould growing in residential
buildings.
These recommendations
apply regardless of the mould species found to be growing in the building.
Further, results from
tests for the presence of fungi in air cannot be used to assess risks to the
health of building occupants.
References
CHMC 2003. Clean-up
Procedures for Mold in Houses. Revised ed. Ottawa: Canada Mortgage
and Housing Corporation. ISBN: 0-660-19227-6.
Chung, Y. J., Coates, N. H., Viana, M. E.,
Copeland, L., Vesper, S. J., Selgrade, M. K., Ward, M. D. W. 2005.
Dose-dependent allergic responses to an extract of Penicillium chrysogenum in
BALB/c mice. Toxicology 209: 77-89.
d'Halewyn, M. A., Leclerc, J. M., King, N.,
Bélanger, M., Legris, M. and Frenette, Y., 2002. Les risques à la santé associés à la présence de
moisissures en milieu intérieur. Québec : Institut national de santé
publique du Québec. 105 p. + appendices.
Health Canada 1995. Fungal Contamination in Public
Buildings: a Guide to Recognition and Management. Ottawa: Health
Canada.
Health Canada 2004. Fungal Contamination in Public
Buildings: Health Effects and Investigation Methods. Ottawa: Health
Canada. ISBN 0-662-37432-0. 47 p.Jaakkola, J. J. K., Hwang, B. F., Jaakkola,
N. 2005. Home dampness and molds, parental atopy, and asthma in childhood: a
six-year population-based cohort study. Environmental Health Perspectives. 113:
357-361.
Rand, T. G., Giles, S., Flemming, J., Miller,
J. D., Puniani, E. 2005. Inflammatory and cytotoxic responses in mouse lungs
exposed to purified toxins from building isolated Penicillium brevicompactum Dierckx and P. chrysogenum Thom. Toxicological
Sciences 87: 213-222.
Wickman, M., Melen, E., Berglind, N., Lennart
Nordvall, S., Almqvist, C., Kull, I., Svartengren, M., Pershagen, G. 2003.
Strategies for preventing wheezing and asthma in small children. Allergy 58:
742-747.
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