A simplistic residential guideline proposed by the Canadian government in December situates household mold as a potential health hazard. In a plainly worded draft guideline, the country’s health agency recommends that citizens “clean thoroughly any mould growing in residential buildings ... regardless of the mould species found to be growing in the building.”

Health Canada also stresses in the residential guideline that citizens can prevent mold growth when they “control humidity and diligently repair any water damage in residences.”

The proposed Health Canada guideline cites scientific animal studies and literature reviews over the past five years that associate indoor dampness with asthma and lung inflammation. The guideline also holds that cell walls of molds contain a certain compound with inflammatory properties, and that mold spores and mycelial fragments contain allergens.

Dr. J. David Miller, a scientific consultant to Health Canada’s Air Health Effects Division, contributed to the drafting of a larger and more detailed document that has been used in Canadian courts. Health Canada’s new guideline is a summary of this document, said Miller, who is a biochemistry professor at Carleton University in Ottawa and also a member of the Biosafety and Environmental Microbiology Committee of the American Industrial Hygiene Association.

With Thomas G. Rand and two researcher from St. Mary’s University in Halifax, Miller and a fellow researcher at Carleton University coauthored one of two papers published in 2005, cited by the Health Canada Guideline, that observed lung inflammation and asthma-like responses in rodents exposed to a common indoor mold or its toxins. Their study, which deals with Penicillium chrysogenum, was published in the journal Toxicological Sciences.
The other referenced study took place not in Canada but in the United States. In that study, University of North Carolina-Chapel Hill environmental scientist Yong-joo Chung and others found “dose-dependent allergic asthma-like responses in mice” from exposure to the same species of mold.

One of that study’s coauthors, Dr. Stephen Vesper, works with the National Exposure Research Laboratory in Cincinnati, under the U.S. Environmental Protection Agency. “The fact is that every indoor environment contains mold,” Vesper told IE Connections. “However, not every mold is found in indoor environments and certainly not at the same concentration in each home. Therefore, it has been our goal to try to understand the difference between a water-damaged home and non-water-damaged home. To this end, we have published many studies describing the development of the Relative Moldiness Index.”

Three such papers containing Vesper’s contributions appear in 2004 editions of Systematic and Applied Microbiology, Journal of Environmental Monitoring, and Journal of Occupational and Environmental Medicine. Vesper’s presentations on this topic also included the Indoor Air Quality Association’s annual meetings in 2005 and 2006, as well as the April 2006 open house sponsored by the Florida Inter-County IAQ Council.

Vesper also detailed how the Relative Moldiness Index has taken on a more practical application since EPA’s collaboration with another arm of the federal government, the U.S. Department of Housing and Urban Development.
“We have now extended this work to the national scale, with the recent completion, in conjunction with HUD, of the American Healthy Home Survey,” he said. “The result has been the development of the Environmental Relative Moldiness Index ... based on the analysis of 36 species in a representative set of nearly 1,100 U.S. homes using a highly standardized dust sample.”

Vesper has used the Environmental Relative Moldiness Index, or ERMI, in epidemiological studies appearing in the August 2006 editions of Environmental Health Perspectives and the Journal of Occupational and Environmental Medicine.

The Health Canada guideline was issued Dec. 23, and a public comment period was announced that would last through at least Feb. 20.

http://www.ieconnections.com/archive/feb_07/feb_07.htm#article1

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