Question: Is there any government or industry standard as to what is deemed an acceptable indoor airborne mold spore levels in Ontario? The electrical inspector refuses to come on our property even though we have had several air test performed. The qualified tester says we have samples of mold but found them to be acceptable. I was hoping for some clarity on this matter.
Answer: Currently there is no government or industry standard as to what is deemed acceptable indoor airborne mold spore levels. However, it’s generally agreed that mold in indoor environments is a health hazard. However, the higher the airborne mold spore levels in a building the higher the health risk. In 2007 Health Canada published the Residential Indoor Air Quality Guidelines: Moulds.
This is what Health Canada’s Residential Indoor Air Quality Guidelines say about exposure limits:
Health Canada considers that mold growth in residential buildings may pose a health hazard.
Health risks depend on exposure and, for asthma symptoms, on allergic sensitization. However, the
large number of mold species and strains growing in buildings and the large inter-individual variability
in human response to mold exposure preclude the derivation of exposure limits. Therefore, Health Canada recommends:
- to control humidity and diligently repair any water damage in residences to prevent mold growth; and
- to clean thoroughly any visible or concealed mold growing in residential buildings.
These recommendations apply regardless of the mold species found to be growing in the building.
Further, in the absence of exposure limits, results from tests for the presence of fungi in air cannot be used to assess risks to the health of building occupants.
So currently there is no acceptable or unacceptable indoor airborne mold Spore levels in Ontario.