Indoor Air Quality: The Hidden Pollutants in Your Home

When most people think of air pollution, they picture smoggy city skies, forest fire smoke, or exhaust from traffic. But did you know that indoor air can sometimes be more polluted than outdoor air? 

Indoor air quality isn’t just about comfort—it’s about your long-term health. The Institute of Building Biology (IBN) refers to our homes as follows: 

In building biology, buildings and rooms are referred to as our “third skin,” which reflects how closely we are connected to our built environment.” 

We now spend almost 90% of our time indoors. Our indoor climate has a direct impact on our health. Poor air quality can lead to allergies, headaches, asthma, as well as throat, nose, and eye irritations.  

Four of the biggest contributors to indoor air pollution are volatile organic compounds (VOCs), radon gas, particulate matter, and mold. All are common, often invisible, and can have a lasting impact on your health over time. Once you understand the source, you can take steps to reduce your exposure.

What Are VOCs and Why Do They Matter?

Have you ever noticed that “new paint smell” or the chemical odor from a freshly opened piece of furniture? Those smells are a result of volatile organic compounds (VOCs)—vapors that are released into the air from certain solid or liquid materials at room temperature.

Some VOCs occur naturally. For example, natural terpenes in wood and natural compounds in essential oils create their distinctive scents.”

But the majority of VOCs in our homes come from petroleum-based products. These include things like:

• Paints and varnishes

• Synthetic carpets and fabrics

• Adhesives and glues

• Furniture finishes

• Cleaning supplies and air fresheners

  
  

Why VOCs Matter for Your Health

VOCs contribute to indoor air pollution, and some can cause headaches, dizziness, or irritation of the eyes, nose, and throat. Long-term exposure has been linked to more serious health effects, depending on the type and concentration of VOCs present. Since most of us spend a significant portion of our time indoors, reducing VOC exposure is important for creating a healthier home.

How to Reduce VOC Exposure at Home

• Choose low-VOC or zero-VOC productsWhen buying paint, finishes, or adhesives, look for labels that say “low-VOC” or “zero-VOC.” Many manufacturers now offer safer alternatives.

• Ventilate during and after renovationsIf you’re painting, laying new carpet, or bringing in new furniture, keep windows open and use fans to increase airflow. Ventilation helps VOCs dissipate more quickly.

• Limit synthetic fragrancesScented laundry products, air fresheners, candles, and scented cleaning products are common sources of VOCs. Opt for natural alternatives or unscented versions when possible.

• Bring in natural materialsSolid wood furniture, natural fabrics such as cotton, wool, hemp, or linen, and non-toxic finishes can reduce the number of synthetic chemicals in your space.

• Give new items time to off-gasIf possible, let new furniture or carpets “air out” in a garage or well-ventilated space before bringing them inside.

What You Need to Know About Radon Gas

Radon is a naturally occurring gas that comes from the breakdown of uranium found in soil, rock, and even groundwater. 

This invisible gas can seep into your home through cracks in the foundation, gaps around pipes, or unfinished floors. Since it has no smell, taste, or color, most people are unaware the gas is there, unless they test for it.

According to Health Canada, “Every building in Canada has some level of radon—but when it accumulates in confined, poorly ventilated spaces like basements, it may spike to unsafe levels.” 

Radon gas becomes a concern when it enters the lungs. It releases tiny radioactive particles that can get trapped in the mucous membranes. Over time, these particles can damage lung tissue and increase the risk of lung cancer.

In fact, the World Health Organization identifies radon as the second leading cause of lung cancer after smoking. Health Canada states that it is the leading cause of lung cancer among non-smokers. Radon is responsible for around 16% of all lung cancer deaths, which translates to over 3,000 deaths annually. 

Radon can be tested for and reduced with the right steps.

Health Canada has set a guideline for radon levels at 200 becquerels per cubic metre (Bq/m³). If your home tests above this level, they recommend taking action to bring it down—ideally within one year, and sooner if the levels are very high.

Testing Your Home

The only way to know if your home has a radon problem is to test for it. Health Canada recommends a long-term test (3–12 months) using a device approved by the Canadian National Radon Proficiency Program (C-NRPP). These detectors are affordable, easy to use, and give a reliable picture of your home’s year-round radon exposure.

It’s also a good idea to retest after major renovations, energy upgrades, or if you install a radon reduction system.

What to Do if Your Levels Are High

If your radon test comes back above the guideline, there are proven solutions. 

• Sealing foundation cracks, 

• improving ventilation, or 

• installing a sub-slab depressurization system that redirects radon safely outside.

Health Canada recommends hiring a C-NRPP–certified professional for mitigation work. Once the system is installed, you’ll need to retest to ensure radon levels have dropped.

Prevention in New Homes

If you’re building a new home, radon prevention can be built in from the start. Things like soil-gas barriers and rough-in piping for radon venting can make it easier to control levels later on.

For more information on radon mitigation and how to test for radon in your home, see Health Canada.

Particulate Matter: Tiny Particles with a Big Impact

Particulate matter (PM) is a mix of tiny particles that float in the air. Indoors, it often comes from dust, pollen, and fibers from carpets or upholstery. Even outdoor pollution and heavy metals can make their way inside and settle into house dust.

Everyday activities can contribute to the problem, such as cooking, burning candles, or smoking indoors.

Why Particulate Matter Matters

People with allergies or asthma, dust and pollen can trigger uncomfortable symptoms. The smallest particles (called PM2.5) are the most concerning. They’re small enough to travel deep into the lungs and even enter the bloodstream, where they can affect long-term health.

How to Reduce Particulate Matter at Home

• Vacuum with a HEPA filter and dust regularly.

• Wash bedding and curtains to decrease allergens.

• Run an air purifier to capture fine particles.

• Ventilate when cooking to clear out smoke and grease particles.

• Choose low-shedding surfaces and fabrics when possible.

What Exactly Is Mold?

When it comes to indoor air quality, mold is one of the most common and often underestimated. Mold is a type of fungus that reproduces by releasing tiny spores into the air. These spores are invisible to the naked eye, but when they land on damp surfaces, they can start to grow and spread.

Indoors, mold is often found in:

• Bathrooms and kitchens

• Basements and crawl spaces

• Around windows or leaky roofs

• On carpets, wallpaper, or upholstery in humid rooms

  
  

Why Mold Matters for Indoor Air Quality

When mold grows indoors, it releases spores into the air. Breathing these in can trigger a range of symptoms, especially for people who are sensitive or allergic. Common issues include:

• Sneezing, coughing, or congestion

• Itchy or watery eyes

• Skin irritation

• Worsening asthma or other respiratory conditions

In more severe cases, long-term mold exposure has been linked to chronic health problems, particularly in vulnerable groups such as children, older adults, or people with weakened immune systems.

Everyday Causes of Mold Growth

• High humidity (over 50%)

• Leaks from roofs, pipes, or windows

• Poor ventilation in bathrooms, kitchens, and laundry rooms

• Flooding or water damage that wasn’t fully dried out

Your Invitation This Month

Things to consider and check as we head into a change of season. VOCs, radon, particulate matter, and mold are four of the most common indoor pollutants. With the right awareness, maintenance, and prevention, you can create a cleaner, healthier home environment.

With gratitude,

Dana and Kim

Optimal Whole Living