Mould in Indoor Environments

By: Patrick Crawford
19th June 2024

One of the most common queries to the Vertex Analytics laboratory are those regarding mould; or specifically, whether mould is present at all! In this blog we delve into the how and why of mould.

Mould Overview
Mould growth in indoor environments poses a complex challenge, affecting both the structural integrity of buildings and the health of their occupants.
Mould is a broad term, and confusion often arises between its synonyms; ‘fungus’, ‘mildew’ and ‘sooty mould’. This can make addressing mould testing queries to the laboratory difficult. However, these terms all refer to various species of fungi of various growth habit which can colonise almost any organic substrate, from fabrics, wood, to carpet and upholstery:

Figure 1. Mould colony growing hidden amongst carpet fibres.

Figure 1 above shows the effects of such growth, which can be spread and persist for weeks before detection by occupants – causing permanent staining and structural damage to infected materials. In serious cases, the structural integrity of construction materials, such as timber, may also be impacted.
Once sufficiently established, mould begins the rapid production of spores as part of its lifecycle, contaminating air and surfaces. These spores can also cause the growth of allergen causing dust mites (refer Figure 2); further compounding indoor air quality to mould affected residences!

Figure 2. Dust mite eating mould Alternaria spores to a mould contaminated plaster wall.

Health and Allergenic Potential
The health implications of mould exposure to both spores and mould fragments (hyphae, detritus) can range from mild allergic reactions to severe respiratory and immunological responses. Common symptoms include:

  • Allergy-like symptoms such as sneezing and itchy eyes,
  • Inflammation of airways,
  • Asthma exacerbation, and;
  • Sensitization of the immune system.

Some moulds produce mycotoxins that can lead to more serious health problems, particularly in individuals with compromised immune systems or chronic lung diseases. In recognition of this, the World Health Organization highlights that exposure to damp and mouldy environments increases the risk of respiratory symptoms and infections.

The Lack of Legislation & Need for Laboratory Testing
One of the major hurdles in managing indoor mould issues is the lack of specific legislation in Australia. Unlike contaminants like asbestos, there are no clear regulatory standards defining acceptable levels of mould contamination. Therefore, most professionals rely on the comparative measure that indoor mould levels should not exceed those outdoors. Additionally, surfaces should be free of actively growing mould colonies, or excessive spore counts; however, such measurements rely on the sampling strategies and interpretations of qualified subject matter experts.
The absence of regulatory guidelines not only makes it difficult to enforce remediation but also complicates insurance claims and legal actions in cases of health problems caused by mould.

Despite the lack of legislation, concerned occupants or site managers may perform their own mould sample tests to confirm a suspected mould issue – for more information, contact our trained mould experts (Mycologists) at:
[email protected]

Mould in indoor environments presents a significant challenge, impacting both the structural integrity of mould affected items and the potential health of occupants. Despite the prevalence of mould-related issues, the absence of specific legislation in Australia complicates the development and enforcement of standard procedures for mould assessment and remediation.
For those seeking to confirm a mould issue, contacting the trained mycologists at Vertex Analytics to occupant-led mould sample tests remains a practical approach until comprehensive regulations are established.

By: Patrick Crawford
Laboratory & Quality Manager