How do you test for mould in the air?
Moulds are part of the kingdom Fungi, which also includes mushrooms and yeasts. Commonly referred to as the singular ‘mould,’ this potentially dangerous living organism is resilient and found in a range of environments across the planet.
As a natural decomposer, mould forms a vital link in the natural ecosystem by breaking down dead organic materials.
Mould grows on a variety of suitable surfaces when conditions are ideal, including natural materials, plant matter, and dead animals. Most types of mould produce spores to reproduce, with these light microscopic particles travelling great distances through the air before settling on a new surface. Mould spore concentrations fluctuate greatly depending on environmental and seasonal conditions.
How much mould is acceptable?
Under normal conditions, the variety and concentration of indoor mould should be similar or less than the surrounding environment. In dry buildings, mould spores and fragments come from outside and settle in everyday dust. While standard levels of mould can be removed easily in dry environments through regular cleaning, excessive mould due to damp indoor environments can create real problems.
Buildings with water damage, drainage problems, or HVAC and ventilation issues can easily become a breeding ground for moulds and other microbes. While affected buildings may present with a musty odour, dangerous levels of mould often go undetected. Several moulds are known to produce toxins and by-products, which can lead to a range of health issues.
Problems caused by mould
Health issues can occur when spores and fragments are inhaled or absorbed through mucus membranes or skin contact. Symptoms range from sneezing and coughing to shortness of breath, skin problems, and severe allergic reactions including asthma. Some people may experience inflammatory responses, which can lead to potentially debilitating symptoms such as brain fog, memory loss, fatigue, and aches and pains.
Damp issues can also cause damage to furniture, carpets, and building materials as the mould attempts to digest organic materials. Potential problems include wood rot, material deterioration, and even structural issues. While mould growth on exposed surfaces can sometimes be detected by colour changes or a general furry appearance, airborne spores and fragments are often not visible to the naked eye.
How to test for mould
In order to assess mould concentrations and damage, air mould samples need to be collected. Prior to air mould sampling, the building should be closed off from the outdoor environment. Sampling the outdoor air is also important to obtain accurate results. There are several known methods to collect mould from the air, including sedimentation and impaction of mould spores onto surfaces.
The active impaction method is common, with a small impaction slide and adhesive collection media attached to a pre-calibrated pump to draw particles through a pump and onto the slide before being sent to a laboratory for testing. At the laboratory, the slides from the cassettes will be viewed under a microscope and analysed for mould types and concentrations.
Laboratory results from air sampling should be analysed together with a detailed assessment of moisture and damp issues in affected building spaces to determine if a building is safe for occupancy. If large concentrations of mould or damage are found, professional remediation is required. In situations where medical or legal considerations are a concern, it’s important to engage qualified professionals for a building and air quality assessment as soon as possible.