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What causes mould in the air?

Joanne Richard
Special to The Weather Network

Tuesday, August 22, 2017, 2:52 PM - The invasion of the merciless mould spore follows Janice Riley throughout the year, but is especially relentless in the summer.

The air is rife with armies of miniscule mould spores, inside and outside, and inhaling spores – the invisible airborne seeds of mould – can trigger a nasty attack of itchy eyes, runny nose and sneezing.

“It’s those mould spores getting into my nose that drive me crazy! It started about 10 years ago and I’m worried that it’ll eventually trigger asthma,” says Riley, a 36-year-old GTA resident. She figured out she was allergic to mould when her allergy symptoms wouldn’t let up throughout the changing seasons.

Mould allergies aren’t seasonal like other allergies. Mould is everywhere around us and in every breath we take – upsetting a mould source sends countless mould spores into the air. It’s widely known that mould spores are easily inhaled and a quite significant trigger for asthma.

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“Unlike plant and tree pollen, the spores are generally invisible to the naked eye and float through the air, landing on surfaces to grow on,” says Shopper’s pharmacist Victor Wong.

Mould spores are released in Canada any time there is no snow on the ground. Outdoor mould counts are at their seasonal peak right now, says Wong. 

"Mould growth usually peaks in late summer to early fall when humidity is the highest and there is an abundance of dead and dying vegetation such as fallen leaves, rotting wood, and vegetation.”

“Mould spores are always present in indoor or outdoor air, as well as almost all building surfaces that can provide nutrients to support growth,” says Toronto mould remediation expert Luis Anacleto, of cleanfirst.ca.

Mould cannot move by themselves like plants, therefore they depend on the forces of nature such as wind to carry them to a food source or food to them, says Anacleto. They consume organic carbon-based compounds to survive.

While the mould spores constantly floating in the air can trigger reactions, the problem worsens when those spores adhere to a wet surface and mould begins to flourish. Mould loves to grow in places where there are water leaks, flooding, or high humidity, adds Anacleto. Deal with visible indoor mould immediately so a small problem doesn’t become a big and costly issue.

According to Dr. David Fischer, mould allergies present with the same symptoms of other allergies: stuffy/runny/sneezy nose and itchy watery red eyes. 

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“One of the key signs that someone is mould allergic and not pollen allergic is that their symptoms are intermittent throughout spring, summer and fall and not in six-to-eight-week blocks like pollen allergies.”

Mould spores do not impact the general population and it is a relative minority of people with allergies who suffer with them – pollen, animal and dust mite allergies are more common, says Fischer, president of Canadian Society of Allergy and Clinical Immunology. “The severity of the symptoms they cause can be especially noted however with asthmatics.”

Meanwhile, treat mould allergies with antihistamines, nasal sprays and eye drops, says Fischer. 

“What it different is that they are required for longer periods of time than for those with pollen allergies which can be frustrating. Immunotherapy can be considered when the other treatments fail, but is likely less successful than for pollen allergies.”

Fight off mould allergy symptoms with tips from expert Victor Wong:

  • Limit outdoor activities during peak seasons when mould counts are highest.
  • Wear a mask, scarf, large rimmed sunglasses, and a wide brimmed hat to reduce the amount of mould spores that are inhaled or deposited on the face. This is particularly important when cutting grass, gardening, picking up leaves, or hiking in deeply forested areas with a lot of vegetation.
  • Immediately shower and wash your hair after going outside, and wash outdoor clothing to prevent mould spores from being carried into the home from skin, hair, and clothes.
  • Keep the windows closed during windy days.
  • Reduce indoor mould exposure by using a HEPA air filter that traps mould spores.
  • Control humidity with proper ventilation such as turning on an exhaust fan when cooking or showering, using a dehumidifier or air conditioner during humid weather.
  • Minimize indoor moisture sources by not over-watering plants, avoid hanging laundry indoors, take garbage out regularly, and make sure there are no leaks in the roof, foundation, or plumbing.

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