What is mould and where is it found?
Mould (fungi) is present everywhere - indoors and outdoors. There are more than 100,000 species of mould. Some of the most commonly found are species of Cladosporium, Penicillium, and Aspergillus. Mould is most likely to grow where there is water or dampness - such as in bathrooms and basements.

How can mould affect your health?
Most types of mould that are routinely encountered are not hazardous to healthy individuals. However, too much exposure to mould may cause or worsen conditions such as asthma, hay fever, or other allergies. The most common symptoms of overexposure are cough, congestion, runny nose, eye irritation, and aggravation of asthma. Depending on the amount of exposure and a person's individual vulnerability, more serious health effects - such as fevers and breathing problems - can occur but are unusual.

How can you be exposed to mould?
When mouldy material becomes damaged or disturbed, spores (reproductive bodies similar to seeds) can be released into the air. Exposure can occur if people inhale the spores, directly handle mouldy materials, or accidentally ingest it. Also, mould can sometimes produce chemicals called mycotoxins. Mycotoxins may cause illness in people who are sensitive to them or if they are exposed to large amounts in the air. Large exposures are typically associated with certain occupations (e.g., agricultural work).

How does mould grow?
All moulds need water to grow. Mould can grow almost anywhere there is water damage, high humidity, or dampness. Most often moulds are confined to areas near the source of water. Removing the source of moisture - such as through repairs or dehumidification - is critical to preventing mould growth.

What is Stachybotrys chartarum?
Stachybotrys chartarum (also known as Stachybotrys atra) is a type of mould that has been associated with health effects in people. It is a greenish-black mould that can grow on materials with a high cellulose content - such as drywall sheetrock, dropped ceiling tiles, and wood - that become chronically moist or water-damaged, due to excessive humidity, water leaks, condensation, or flooding.

How can you tell if Stachybotrys chartarum is present in your home?
Many moulds are black in appearance but are not Stachybotrys. For example, the black mould commonly found between bathroom tiles is not Stachybotrys. Stachybotrys can be positively identified only by specially trained professionals (e.g., mycologists) through a microscopic exam.

How can Stachybotrys chartarum affect your health?
Typically, indoor air levels of Stachybotrys are low; however, as with other types of mould, at higher levels health effects can occur. These include allergic rhinitis (cold-like symptoms), dermatitis (rashes), sinusitis, conjunctivitis, and aggravation of asthma. Some related symptoms are more general - such as inability to concentrate and fatigue. Usually, symptoms disappear after the contamination is removed.

There has been some evidence linking Stachybotrys with pulmonary hemosiderosis in infants who are generally less than six months old. Pulmonary hemosiderosis is an uncommon condition that results from bleeding in the lungs. In studied cases of pulmonary hemosiderosis, the exposure to Stachybotrys came from highly contaminated dwellings, where the infants were continually exposed over a long period of time.

What should you do if mould is present in your home or apartment?
Although any visible mould can be sampled by an environmental consultant and/or analysed by a laboratory specializing in microbiology, these tests can be very expensive - from hundreds to thousands of dollars. There is no simple and cheap way to sample the air in your home to find out what types of mould are present and whether they are airborne. Even if you have your home tested, it is difficult to say at what levels health effects would occur. Therefore, it is more important get rid of the mould rather than find out more about it. The most effective way to treat mould is to correct underlying water damage and clean the affected area.

Visit our mould testing and solution section 

How should mould be cleaned?
Mould should be cleaned as soon as it appears. Persons cleaning mould should be free of symptoms and allergies. Small areas of mould should be cleaned using a detergent/soapy solution or an appropriate household cleaner. Gloves should be worn during cleaning. The cleaned area should then be thoroughly dried. Dispose of any sponges or rags used to clean mould.

If the mould returns quickly or spreads, it may indicate an underlying problem such as a leak. Any underlying water problems must be fixed to successfully eliminate mould problems. If mould contamination is extensive, a professional abatement company may need to be consulted.

Will my health or my child's health be affected, and should we see a physician?
If you believe that you or your children have symptoms that you suspect are caused by exposure to mould, you should see a physician. Keep in mind that many symptoms associated with mould exposure may also be caused by many other illnesses. You should tell your physician about the symptoms and about when, how, and for how long you think you or your children were exposed.