Understanding exposure to mould

Understanding Exposure To Mould

  • In understanding how exposure to mould might cause or contribute to illnesses it is useful to distinguish among the meanings of the words allergenic, pathogenic, and toxic effects that exposure to something might explain.
  • Allergenic – causing allergic Reactions – rhinitis, sinusitis, asthma, skin problems, other
  • Pathogenic – Produces Infections, caused by pathogens such as bacteria or viruses
  • Mould Smell Illnesses – headaches, vomiting, nausea, blocked noses, and asthmatic [MVOC’s–DF]
  • Toxic Illnesses – where mould is involved, may be produced by mycotoxins that are produced by some, not all, mould species.

Note that even for a “toxic” mould species; the actual level of toxicity can vary significantly depending on growing conditions such as the growth substrate (what the mould is feeding-on), humidity, moisture, and other factors.

  • Respiratory Illnesses –
  • Digestive Tract Illnesses – liver diseases: fibrosis and necrosis; vomiting, diarrhoea, intestinal bleeding
  • Reproductive Illnesses – infertility, variations in reproductive and hormonal cycle
  • Highly Serious Illnesses – Cancer, Tuberculosis, Lupus, Sudden Infant Death Syndrome (SIDS), Chronic Fatigue Disorder (CFS), Fibromyalgi, Epstein-Barr, aspergillosis

Microbial Volatile Organic Compounds:

  • MVOCs
  • (Microbial Volatile Organic Compounds)
  • MVOCs & Mouldy Odours
  • Microbial Volatile Organic Compounds (MVOCs) are gases produced by mould. The musty odour which you might smell from mould is caused by MVOCs. These odours are actually chemicals which are produced my moulds during some parts of the mould’s growth cycle.
  • Laboratory experiments have identified over 200 compounds as MVOCs. They are commonly made up of strong chemicals such as aldehydes, benzenes, tulolenes and many more.
  • When Does Mould Produce MVOCs
  • Some moulds produce different MVOCs depending on conditions such as how much moisture is available and what material the mould is growing on. However MVOCs are only produced at all when mould is actively growing (which depends on certain conditions such as humidity, temperature, air pressure and light.This is because MVOCs are the waste products created by mould as it grows.
  • So if you can smell MVOCs from mould it is a sign that mould is actively growing in your home and that you should remediate the mould problem as soon as possible.
  • More Mould Signs
  • Removing MVOCs
  • Even if you cannot see mould, the musty smell of MVOCs can alert you to the presence of mould growing somewhere in your home hidden from view. MVOCs can be doing damage to your health even if no mould growth is visible in your home.
  • Where Mould Grows get a Mould Inspection for help with finding mould in your home.
  • Once mould growth has been removed from a home some MVOCs may still be present as they can remain ingrained in permeable items such as clothes, carpets, upholstered furniture and curtains. These mouldy odours can be hard to remove.
  • Symptoms Caused by MVOCs
  • MVOCs can cause symptoms like headaches, nausea, dizziness and fatigue. MVOCs may also irritate the eyes and the mucus membranes of the nose and throat. However, because research on MVOCs is still at an early stage, not everything is yet known

about MVOCs and our reactions to them.


  • Mycotoxins are toxins produced by some species of mould (myco means fungal). These mycotoxins are some of the most toxic substances in existence.
  • Mycotoxin Types
  • Some of the different types of mycotoxins are:
  • •Aflatoxins (produced by Aspergillus) – includes Aflatoxin B1, B2, G1, G2, M1 and M2
  • •Ochratoxin – includes Ochratoxin A, B, and C
  • •Trichothecene (produced by Stachybotrys) – includes Satratoxin-H, Vomitoxin and T-2 mycotoxins
  • •Fumonisins – includes Fumonisin B1 and B2
  • •Zearalenone
  • Killing Mycotoxins
  • Mycotoxins aren’t actually alive like mould spores. So when we talk about “killing mycotoxins” it really means breaking down mycotoxins and their toxicity so they are no longer dangerous to humans.
  • It takes fire at 500 degrees Fahrenheit (260 degrees Celsius) for half an hour or fire at 900 degrees Fahrenheit (482 degrees Celsius) for 10 minutes to destroy trichothecene mycotoxins.
  • Ozone is supposed to kill most or all mycotoxins. However the level of ozone you need to kill mycotoxins is not safe for humans. So the use of an ozone generator there must be no one in the house..
  • Mycotoxins do eventually break down and lose their toxicity after some time. Some types of mycotoxins can take several years though, for example trichothecene mycotoxins which are among the most resilient.
  • How small are Mycotoxins?
  • Like mould spores, mycotoxins are too small for us to see with the naked eye. Mycotoxins are as small as 0.1 microns. Mould spores are between 1 and 20 microns. Human hair, for comparison, is about 100 microns thick.
  • How do Mycotoxins Enter the Human Body?
  • When people are around toxic mould they are usually exposed to airborne mycotoxins by breathing them in. These mycotoxins end up in the lungs and cause breathing problems and other severe symptoms.

What are VOCs?

Volatile organic compounds are chemicals used to manufacture and maintain building materials, interior furnishing, cleaning products and personal care products. “Volatile” means that these chemicals evaporate or can easily get into the air at room temperature. “Organic” means these chemicals are carbon based. The term “chemical emissions” refers to VOCs as they evaporate into the air from products.

Studies by the U.S. Environmental Protection Agency (U.S.EPA) and other researchers have found that VOCs are common in indoor environments and that their levels may be two to a thousand times higher than outdoors. There may be anywhere from 50 to hundreds of individual VOCs in the indoor air at any one time. Some may produce objectionable odours at very low levels, but many have no noticeable smell. Many VOCs are irritants and can cause headaches, eye, nose and throat irritation and dizziness. Long-term exposure to certain VOCs may lead to chronic diseases or cancer. At high concentrations, some VOCs are toxic.

Where are VOCs Found?

The majority of VOCs found in the indoor environments and originate from building materials, indoor furnishings, cleaning supplies, consumer products and processes, such as printing, cooking, hobbies, cleaning, interior renovations and pesticide applications.

Results from studies conducted as part of the state of Washington’s East Campus Plus Program showed that 96 percent of the VOCs found in a large office building following construction resulted from the materials used to construct and furnish the building.

Volatile organic compounds are found in a number of products, including:

Furniture, Paint, Drywall, Bedding, Paint strippers, Adhesives/glues, Solvents, Upholstery and other textiles, Carpet, Cleaning products, Copy machine toners, Office supplies, Electronic equipment, Dry-cleaned clothing, Building materials

A few common VOCs in homes, offices and schools include:

Formaldehyde, Decane, Butoxyethanol, Isopentane, Limonene, Styrene, Xylenes, Perchloroethylene, Methylene, Chloride, Toluene, Vinyl chloride

Means of Chemical Exposure

There are three ways in which people are exposed to chemicals: ingestion, dermal absorption and inhalation. Ingestion occurs when materials that have chemical content are eaten or placed in the mouth.  Dermal absorption occurs when chemicals come into contact with the skin.  While these are both significant forms of chemical exposure, the majority of everyday chemical exposure occurs through the air we breathe in our homes, offices, schools and other indoor environments. These airborne chemicals are commonly referred to as volatile organic compounds (VOC’s).

Health Problems Caused by Volatile Organic Compounds (VOCs)

Many factors determine if people get sick from exposure to indoor pollutants, including the type of pollutant, its concentration, the duration of exposure, the method of exposure (inhalation, ingestion or dermal absorption) and the individual sensitivities of those exposed. Building conditions, such as the amount of ventilation, age of the building, indoor temperature and humidity levels, can also have an impact.

Health Impacts

Indoor Air Quality and Your Health

People spend the majority of their time indoors, where they face significant health risks due to repeated exposure to air pollutants in their homes, offices, schools and other indoor environments. Exposure to these pollutants can lead to numerous immediate and long-term health problems. Common pollutants include respirable particles, chemical emissions, mould spores, animal allergens, radon, combustion gases, smoke and pesticides.

Immediate or Acute Health Effects:           

  • Headaches •Eye, nose and throat irritation •Allergic skin reaction •Difficulty breathing •Nausea and/or vomiting
  • Confusion •Loss of coordination •Dizziness •Fatigue •Nosebleeds

Health Problems Associated With Mould

Health problems caused by mould may be acute, which occur immediately, or within a few days of exposure. Health problems may also be chronic, which are long-term health effects that might not occur immediately.


Acute health problems associated with indoor mould exposure include:

  • Irritated eyes, nose and throat
  • Headache
  • Difficulty with concentrating or short-term memory

These symptoms together are often called sick building syndrome, but are more correctly referred to as building-related symptoms. Generally, acute symptoms resolve when the person is removed from exposure. However, mold exposure may also aggravate chronic conditions, such as allergic rhinitis (hay fever) and  hypersensitivity pneumonitis, and may trigger asthma and allergy attacks.

Overview of Indoor Air Quality (IAQ)

Indoor Air is 2 to 5 Times More Polluted Than Outdoor Air

Most of our exposure to environmental pollutants occurs by breathing the air indoors. These pollutants come from activities, products and materials we use every day. The air in our homes, schools and offices can be 2 to 5 times more polluted, and in some cases 100 times more polluted, than outdoor air.

People Spend 90 Per cent of Their Time Indoors

Indoor air quality is a significant concern, because when the hours spent sleeping, working in offices or at school are added up, people on average spend the vast majority of their time indoors where they are repeatedly exposed to indoor air pollutants. In fact, the US Environmental Protection Agency (USEPA) estimates that the average person receives 72 percent of their chemical exposure at home, which means the very places most people consider safest paradoxically exposes them to the greatest amounts of potentially hazardous pollutants.

What Contributes to Poor Indoor Air Quality?


The primary sources of indoor exposure to airborne chemicals are products used in interior environments, including furnishings, building materials and other household and office products, that can emit thousands of volatile organic compounds (VOCs) and particles into the air. Of all the culprits that can affect IAQ, chemical emissions are the most harmful as they can contribute to a wide range of health effects.


Moisture problems are another common source of indoor air pollution as they can lead to indoor mould growth. Mould can also emit VOCs and particulates, compromising indoor air quality and leading to negative health effects.  Since it is impossible to eliminate mould spores, the best way to reduce the impact of mould on indoor air quality is to prevent or promptly repair the moisture problems that enable mould growth.


The particles emitted from products such as furnishings, building materials and other household and office products are another source of indoor air pollution. Airborne particulates can also come from dirt and dust that is tracked in from outdoors. Particulates can trigger allergies and other respiratory problems in many people.  Installing walk-off mats at doorways and changing air filters regularly are both good strategies to limit these pollutants.

Poor Ventilation

Most of the buildings in which people spend the majority of their time are tightly sealed and insulated to keep out unconditioned outdoor air. Furthermore, most ventilation systems are designed to bring in very little outdoor air and instead recirculate the indoor air that has already been heated or cooled. While this strategy is effective for minimizing energy costs, it can have a negative impact on indoor air quality.

Contact MouldandMore/ MouldremovalPerth for  mould testing/ mould investigating/ mould inspections/ mould removal/ mould cleaning/ black ceiling mould removal/ mould issues/ Indoor sanitising/odours/odour treatments/germs/bacteria/bacteria testing.