What is Indoor Air Quality (IAQ)?

indoor air quality montreal quebec

Indoor air quality (IAQ) refers to the quality of air in an enclosed environment. Most often, IAQ is used in reference to our homes, schools and workplaces. These are the places in which we spend the majority of our time.

The biggest concern to indoor air quality is thus the accumulation of harmful pollutants such as mold spores, VOCs, radon, dust and pollen within these environments.

Unfortunately, indoor air pollution is a real, yet often overlooked, problem. Living in Montreal, we tend to take for granted that we have everyday access to clean air, so we never even question the quality of the air inside our homes and offices. But if we neglect our indoor environments, pollutants can and will start to accumulate, regardless of the size, state or age of your property.

By understanding what the most common indoor air pollutants are and where they come from, we can improve our indoor air quality and better protect our health.

Common indoor air pollutants and allergens

The items we keep in our homes and the activities we engage in while we’re at home all contribute to overall indoor air quality. Even the very materials our homes are made of can be the source of multiple indoor air pollutants.

In our daily rush to get things done, we’ll often ignore an unfamiliar smell from the kitchen, a small patch of mold in our bathroom or a broken exhaust fan. Ultimately what happens is our indoor air quality suffers as indoor air pollutants start accumulating. Whether biological or chemical in nature, these contaminants have the capacity to affect our health, our mood and our productivity.

These are some of the most common indoor pollutants and allergens [1]:

  • Dust
  • Pollen
  • Mold
  • Cockroaches and other insects
  • Cat and dog dander
  • Skin cells
  • Volatile Organic Compounds (VOCs)
  • Formaldehyde
  • Bacteria
  • Second-hand smoke
  • Carbon monoxide
  • Lead
  • Radon
  • Smog

Sources of indoor pollutants and allergens

Some indoor pollutants and allergens are a natural part of the indoor environment while others are created by off-gassing of furniture, paint, or cleaning products.

Here are some of the biggest contributors to indoor air pollution:

  • Carpets and rugs
  • Soft furniture
  • Stuffed toys
  • Curtains and drapes
  • Damp areas & humidity
  • Indoor plants
  • Bedding (mattresses, pillows, duvets, etc.)
  • Furniture off-gassing
  • Cockroach debris and rodent infestations
  • Foundation cracks (radon)
  • Scented candles, fragrances and perfumes
  • Cleaning products
  • Paint

And yes, even our beloved pets can be a source of indoor allergens.

Health effects of poor indoor air quality

Just like the food we eat, the air we breathe has a tremendous effect on our health. And since we are constantly breathing, air is constantly flowing through our bodies. Any pollutants or particulates present in the air are thus also present in our bodies.

If you’re continuously exposed to indoor air pollutions, your body will start showing signs of health problems such as:

  • Worsening of asthma and allergies
  • Decreased productivity
  • Learning difficulties
  • A wide range of symptoms associated with Sick Building Syndrome. [2]

We tend to overlook indoor air quality since we’re more focused on the things that impact us in more obvious and immediate ways. But our indoor air is crucial to our health, mood and overall well-being. Taking steps to improve indoor air quality means taking good care of your health in the long term.

How to improve IAQ

Often indoor air quality is not in our control. For example, if we live in a big city with many factories, cars and other sources of carbon emissions, there is a big chance that this pollution will make its way into our homes. The good news is that there are actions we can take in order to minimize the effects of environmental pollutants and to improve indoor air quality inside our homes.

Improve ventilation, improve IAQ

Proper ventilation is essential to achieving healthy indoor air quality. We need to ventilate our homes in order to release stale, polluted air and allow fresh air to enter. There are several ways to accomplish this:

  • Open windows and doors regularly.
  • Use exhaust fans when showering or cooking in order to reduce humidity that contributes to mold growth.
  • Assess your HVAC system to ensure optimal performance.
  • Get your air ducts cleaned.
  • Replace air filters

Get rid of carpets and rugs

Sure, carpets are warm and comfortable, but if you think about all the things they absorb during their lifetime, it becomes clear that they need to go. Even if you clean your carpets regularly, it’s simply impossible to remove all of the dust and debris that settles inside the fibres. Over time, these carpets worsen indoor air quality and trigger allergies, asthma and other health problems.

Remove mold quickly


Molds are fast-growing fungi that love moisture. They are often found growing on nutrient-rich items such as drywall, wood, carpets and food. Due to their microscopic size, they can become airborne and be inhaled easily. Some molds can cause allergies and worsen asthma while others can produce harmful mycotoxins that result in pathogenic and toxigenic reactions. [3]

If you find mold growing in your home, you should remove it as quickly as possible so that it doesn’t affect your indoor air quality.

Moisture control

Since moisture is the main cause of all mold problems [4], controlling moisture is one of the best ways to prevent mold and improve indoor air quality. Checking your home’s exterior for cracks and water drainage issues is a good idea, especially in the spring when snow accumulated during the long Montreal winter begins to melt and penetrate our homes. You should also check your relative humidity level indoors, ensuring that it does not surpass 50%.

Clean your home regularly

Keeping your home clean is essential to keeping indoor air pollutants and allergens at bay. This includes:

  • Vacuuming
  • Wiping surfaces
  • Washing curtains, drapes and other fabrics
  • Washing your bedding (preferably on the sterilize setting of your washer)


  1. American Academy of Allergy Asthma & Immunology n.d., Indoor Allergens, AAAAI, accessed 26 Feb 2020, https://www.aaaai.org/conditions-and-treatments/library/allergy-library/indoor-allergens.
  2. EPA 2020, Introduction to Indoor Air Quality, Environmental Protection Agency, accessed 26 Feb 2020, https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality.
  3. WebMD n.d., Moisture and Mold Problems: Preventing and Solving Them in Your Home, accessed 26 Feb 2020, https://www.webmd.com/lung/mold-mildew#1.
  4. Health Canada 2015, Addressing moisture and mould in your home, Government of Canada, accessed 26 Feb 2020, https://www.canada.ca/en/health-canada/services/publications/healthy-living/addressing-moisture-mould-your-home.html.