We may spot mould on an aging peach or on a loaf of days-old bread. We may even eat edible mould in certain types of cheeses. Mould can also lurk in our basement walls, on window panes, above ceiling tiles, on bathtub tiles, and in any other spots in our homes where moisture may be. And the mould that hides in our homes can be harmful to our health.

What is mould?

Mould is a type of fungus that produces tiny spores. Those spores can contain irritants and allergens and are so small that a person can breathe them in without noticing.

How can mould harm our health?

When inhaled, mould spores can irritate the eyes, nose, and throat. Coughing, wheezing, and shortness of breath, as well as allergic reactions can result. Mould can even worsen the symptoms of asthma, though it is unclear whether mould causes the respiratory ailment. People with weakened immune systems are at heightened risk of developing infections due to exposure to mould.

What triggers mould growth?

Mould spores float around out in the open air all the time, invisible to the eye. But give the spores a damp, moist environment - with excessive humidity and something to grab onto, like a wall or furniture - and you could soon see the tell-tale signs of mould growth: a musty scent and the presence of mottled stains or discolouration on walls, floors, windows, and carpets. Mould is common after floods, with water damage from leaks or other sources, and in spots around the home that get poor ventilation. Everyday goings-on around the house can cause mould, too, especially in the kitchen and bathroom, where all of the steamy cooking and showering go on. From time to time, mould develops in heaters, air conditioners, humidifiers, and other household appliances that use water.

If I spot mould, how do I clean it?

A small patch of mould can be cleared away with simple dish detergent and water. Harsh bleach isn't necessary. To keep from inhaling the spores, you may want to wear gloves and a mask to cover your mouth. Mould that has spread over a larger area calls for a professional clean-up. Either way, the next step must be to take care of the underlying cause of the mould so it does not return.

How can I prevent mould?

The best way to deal with mould is to not to get it in the first place! It may not be possible to keep out all mould spores, but you can take steps to make yours a mould-unfriendly home:

  • Repair any leaks or water damage ASAP. Water left to stand or soak into carpets, walls, or furniture is a mould spore's dream come true.
  • Circulate the air in your home. Use fans or open the windows when you can to keep a balance between inside and outside air.
  • Always use the exhaust fans in the kitchen and bathroom. Check them periodically to ensure they are clean and working properly.
  • Make sure that dryer hoses are not leaking moisture and steam inside.
  • Clean and disinfect humidifiers, dehumidifiers, air conditioners, and other appliances that use water.
  • Consider placing a dehumidifier in moisture-prone zones of your home.
  • Watch out for over-watered plants; mould can grow on the pots.
  • Vacuum regularly to reduce dust, which mould loves to cling to. Check out the special filters available for picking up the tiniest of microbial contaminants like mould.

Amy Toffelmire