Everything You Need to Know About Indoor Air Quality

When we think of poor air quality, we often think of the outdoors, polluted by smog, car exhaust and toxic emissions that are the byproduct of industry. Outdoor air pollution is an epidemic that is responsible for millions of deaths worldwide on a yearly basis.

Though it may not be as apparent, indoor air quality is an equally alarming concern from a health and safety standpoint. Canadians spend upwards of 90% of their time indoors. Breathing in contaminated air can lead to a wide range of short-term and long-term health effects, including allergies, asthma and an increased risk of stroke and heart conditions.

Sadly, most people are not even aware of the presence of air contaminants in their home, despite the widespread health effects. Only 1% of Canadian households report poor indoor air quality in their homes, though 5% believe someone in their household has suffered a health problem due to poor indoor air quality and 13% report a presence of mold/mildew in their homes.

In this guide, we are going to explore the questions everyone has been asking about indoor air quality: What are air pollutants? What causes them to amass in the home? What are the health effects of poor indoor air quality? Finally, how can you identify and remediate poor indoor air quality? Let’s get to these questions and more!

Who is affected by poor indoor air quality?


Everyone is vulnerable to ill health effects directly attributable to poor indoor air quality, including residents, workers, guests, and pets. However, children, pregnant women, and the elderly are more vulnerable. As you might expect, the more prolonged the exposure and the more severe the presence of pollutants, the more likely a person is to develop ill health effects. People with pre-existing heart conditions such as angina, arrhythmia, or hypertension are more vulnerable, as are those with pre-existing breathing and lung conditions such as asthma or chronic obstructive pulmonary disease (COPD).

What are examples of indoor pollutants?

Broadly put, an indoor air pollutant is any kind of airborne gas, vapour, particulate, microbial contaminant, or substance that can cause negative health effects. Health Canada divides air contaminants into the following categories.

Biological Pollutants

  • Mold
  • Mildew
  • Fungi
  • Pollen (aeroallergens)
  • Dust Mites
  • Bacteria (such as Legionella)

Chemical Pollutants

  • Carbon Monoxide (CO)
  • Nitrogen Dioxide (NO2)
  • Formaldehyde
  • Asbestos
  • Ozone
  • Lead
  • Particulate Matter
  • Volatile Organic Compounds (VOCs) – any substance that contains carbon and off-gases at room temperature. Household products that may contain VOCs include nail polish, aerosol spray products, and air fresheners.

Radiological Pollutants

  • Radon

Some contaminants on this list are not typically present in the home, but may be emitted under certain circumstances. An example would be leaving the car to idle in the garage, thus emitting toxic CO and other harmful contaminants.


What causes poor indoor air quality?

According to the Canadian Centre for Occupational Health and Safety, the most common sources of indoor air contaminants are as follows:

  • Occupants (tobacco smoke, perfume, body odours, CO2)
  • Materials (dust, gases, asbestos, fiberglass)
  • Cleansers/solvents/pesticides, etc. (VOCs, toxic vapours)
  • Off-gas emissions from carpets, furniture, and paints (gases, vapours, odours)
  • Carpets and fabrics (dust mites)
  • Damp areas (mold, bacteria, fungi)
  • Photocopiers, electric motors, air cleaners (ozone)

In the home, the most likely causes of poor indoor air quality come from off-gassing, insufficient ventilation, and damp areas caused by water damage or condensation buildup.

What are the health effects of poor indoor air quality?


Short-term effects are described as health problems that can occur immediately following brief exposure including fatigue, headache, dizziness, coughing, sneezing, wheezing, or irritated eyes, nose, throat, and skin. These symptoms may on-set immediately or develop after a few hours. Typically, these short-term symptoms will leave you once you leave the affected area. In some people these symptoms may only be slightly discomforting; in others the complications can be quite severe or even deadly. Even in the short-term, those with lung or heart conditions may experience more severe complications that require treatment.

Long-term health effects are described as health problems that may occur following continuous or repeated exposure over a period of months or years. In the long-term, indoor air contaminants are potentially deadly. Contaminants such as asbestos and tobacco smoke are known to be carcinogenic. Lead can cause brain damage. Animal dander may carry infectious diseases. Prolonged exposure to air pollution damages the arteries, potentially leading to a heart condition.

How can you identify poor indoor air quality?

Air quality testing (also known as air monitoring or air sampling) will identify the presence of pollutants such as asbestos, mold, and VOCs in your home’s air. You can’t remediate indoor air problems and start breathing freely once more unless you know exactly what contaminants you are dealing with and where they are coming from.


Annual air quality monitoring is also recommended to ensure the air in your home remains safe.

How do you improve indoor air quality?

The method you take to improve indoor air quality will depend on the source. Below are a few things you can do in your home to prevent the problems that most often lead to poor air quality.

Keep Your Home Clean

Vacuum on a weekly basis at minimum to remove allergens like pollen and pet dander from the floors. Use a vacuum cleaner with a HEPA filter and clean it on a regular basis. Do not allow dishes or damp clothes to accumulate. Keep a close eye on your appliances, plumbing, and home fixtures to spot problems early, such as water leaks or dust build-up, before they turn into a bigger problem down the road.

Control Humidity Levels

Ideal home humidity levels are around 30%-50%. Invest in a dehumidifier to keep your indoor air at a comfortable temperature – an air conditioner also works in the summer months.

Ensure Adequate Ventilation

Make sure your clothes dryer, and stove/oven are all well ventilated. Always use the exhaust fan when cooking, using the dishwasher, or showering/bathing. Proper air exchange and air circulation are also important in maintaining optimal air quality in your home.

Repair Water Damage

If you have mold or mildew growth due to water damage, you are well advised to hire a mold remediation company. If the water damage is due to an issue like a leaky basement or foundation crack, hire a foundation repair company to permanently seal the crack and keep your basement dry.

Smoke-Free Home

Second-hand cigarette smoke is deadly, not to mention dangerous considering the well-documented fire risks of indoor smoking. Protect yourself and your family by banning smoking in your home. If you are a smoker, speak with your doctor about developing a smoking cessation plan.

Test for Radon

Radon is a colourless, odourless, carcinogenic gas that can seep up from the ground into your home through small cracks and openings. Radon exposure is the second-leading cause of lung cancer in Canada. Conduct a radon test to determine if your home has elevated radon levels. If found, begin radon remediation steps immediately to prevent any further risk to you and your family.


We spend half our lives at home, and over 90% of our time indoors. Shouldn’t our homes be as safe and healthy as possible? If you have any concerns about the quality of the air in your home or you believe you have experienced ill health effects due to your home’s air, we can help.

Source: mold busters

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