What is mould?

Mould is part of the fungus family, along with mushrooms and yeast. Mould spores are very small and they travel easily through the air. For example, if you have mould in your basement, the spores can travel through your home's ventilation system to other areas, like your child's bedroom. There are many types of moulds and these can be found both indoors and outdoors. This resource focuses on indoor mould that can be found around the home or the child care setting.

Where can I find mould?

Mould grows mainly on building materials such as wood, drywall, carpet, wallpaper and foundation walls where there is excess moisture, dampness or water accumulation. Mould is usually found in basements, bathrooms and kitchens, in humidifiers, air conditioners, air ducts, air filters, furnaces or drip pans.

Mould is difficult to recognize because it often looks like a stain or a discolouration. It can range in colour from white to orange, and from green to black. Mould often smells musty, earthy or a little bit like alcohol.

The best way to identify mould is to dab the suspected area with a little bit of chlorine bleach. If the colour changes or disappears, then it is probably mould.

How can mould affect children's health?

Since mould is everywhere, everyone is exposed to some mould everyday. However, infants and young children are among those most at risk for a mould-related reaction. When mould spores are inhaled, they can cause or trigger mould allergies, asthma and respiratory problems. You can also get exposed to mould through skin contact.

Allergic reactions and asthma attacks are the most frequent problems associated with exposure to mould. However, mould exposures can also cause the following symptoms:

• wheezing
• difficulties breathing
• sore or watery eyes
• throat irritation
• dry cough
• skin irritation
• headaches
• fever
• fatigue

What is Stachybotrys?

Stachybotrys atra is a type of mould that can produce toxins. It is usually dark green to black in colour, and is slimy when wet. However, it is not the only type nor the most common type of black mould. It grows slowly in dark and humid areas that have been wet for several days.

This type of mould can cause serious health problems when it is disturbed (for example during cleaning). It cannot be destroyed by bleach, and is most dangerous after drying because the dry spores can travel easily through the air.

People who breathe live or dead spores may experience cold and flu-like symptoms such as sore throats, headache, and nausea. Heavy exposure can affect the lungs.

If you suspect that this type of mould is growing in your house or child care setting, contact your local public health unit for inspection. Only a trained professional should do the detection and removal of this type of mould.

How can I clean mould?

• Areas where mould is growing must be cleaned, disinfected, and the source of moisture removed, otherwise the mould will come back. If you have experienced a flood, do not try to clean mould yourself, consult a professional.
• Only chlorine bleach can kill mould on contact. To protect yourself when working with chlorine bleach, wear a face mask, gloves, safety goggles and a shirt with long sleeves. Make sure that your work area is well ventilated. 
• Recommended steps to clean surface mould
  • Soak the mouldy area in chlorine bleach for 15 minutes.
  • Wash the area with a bleach cleanser made of one part chlorine bleach, four parts water and a few drops of non-ammonia dishwashing detergent, rinse and dry quickly.
  • Do not mix ammonia and bleach because a toxic gas will form.
  • Throw out any mouldy items that cannot be cleaned and thoroughly dried.

How can I prevent mould growth?

1. Control the moisture level in your house
   • Keep the relative humidity between 50 and 30 percent.
   • Avoid drying laundry indoors.
   • Vent clothes dryers outside.
   • Avoid using humidifiers.
   • Avoid using carpets and rugs.
   • Install good ventilation systems in bathrooms and kitchens.
     
2. Keep things clean and dry
   • Check for water leaks and dampness in attics and basements.
   • Repair plumbing leaks.
   • Change the filters on your furnace regularly.
   • Clean drip pans in your air conditioner, refrigerator and dehumidifier frequently.

For more information
Canada Mortgage and Housing Corporation, Fighting Mold (www.cmhc-schl.gc.ca/en/burema/gesein/abhose/abhose_ce08.cfm)

British Columbia Ministry of Health: Indoor Air Quality: Moulds and Other Biological Contaminants (www.hlth.gov.bc.ca/hlthfile/hfile65b.html)

Healthy Spaces © was developed by the Canadian Institute of Child Health (www.cich.ca) in partnership with the Canadian Child Care Federation (www.cccf-fcsge.ca), funded by Human Resources Development Canada. Healthy Spaces (www.cfc-efc.ca/healthyspaces) is housed on Child & Family Canada (www.cfc-efc.ca).