What a study of water-damaged Australian homes tells us about mould

What did the researchers study?

The 2017 paper Comparison of Mold Populations in Water-Damaged Homes in Australia and the United States examined settled dust from living rooms and bedrooms in 76 south-eastern Australian homes being investigated for possible water damage and mould contamination. [1]

The researchers used mould-specific quantitative PCR, a DNA-based laboratory method, to measure 36 types of mould. They calculated an Environmental Relative Moldiness Index, or ERMI, then matched each Australian home with a US home having a similar ERMI score.

The question was whether a measurement scale developed using US homes might also help researchers estimate mould contamination in water-damaged Australian homes.

What did they find?

All 36 mould types in the testing panel were detected across the Australian sample. This does not mean every type was present in every home.

Many of the mould types had comparable concentrations in the Australian and ERMI-matched US homes, although there were differences between individual types. The authors suggested that the US scale might offer a useful estimate for the Australian homes studied, while calling for an Australian-specific scale and broader research. [1]

What the study cannot tell us

• It is not a national survey. The sample was small, geographically limited and selected because homes had suspected mould problems. It cannot tell us how common mould is across all Australian homes.
• It did not measure residents' health outcomes. Discussion of asthma draws on other research; this comparison did not establish disease causation.
• It did not test a treatment. There was no before-and-after trial of ventilation, cleaning or remediation.
• A dust score is not a safety certificate. It does not identify the source of moisture or establish whether a particular home is safe for a particular person.

An important caution about ERMI

The US Environmental Protection Agency currently describes ERMI as a research tool and does not recommend its use outside research. [2] The paper should therefore not be read as a recommendation that every household purchase ERMI testing, or as EPA endorsement of a commercial testing service.

HOUSE TUNE is sharing this paper to explain the research, not to present ERMI as an approved Australian compliance test or medical diagnostic tool.

What does this mean for your home?

Separately from this study, Australian public-health guidance explains that mould needs moisture to grow and recommends keeping indoor spaces well-ventilated, clean and dry. [3] Practical attention should include leaks, water ingress, condensation and extraction of moisture—not just the appearance or colour of mould.

Black colour alone does not establish the species or toxicity of a mould. Nor does a freshly cleaned surface show that an underlying moisture problem has been resolved.

If mould is extensive or keeps returning, seek appropriately qualified advice about the moisture source and remediation. If you have symptoms or concerns about your health, speak with a healthcare professional. This article is general information, not a diagnosis or a DIY remediation guide.

The HOUSE TUNE approach

Our focus is understanding the home's conditions, explaining findings clearly and coordinating practical improvements with appropriate specialists. Useful research helps us ask better questions; it should not be used to promise medical outcomes.

Book a home consultation to discuss your ventilation and moisture concerns.