Poor indoor air quality during the winter is a silent but significant health threat, and it often gets exacerbated by our own efforts to stay warm. As temperatures drop, we seal our homes to keep out the cold, inadvertently trapping indoor air pollutants from everyday household activities and products. Forced-air systems, air fresheners, and the increased use of fireplaces and portable heaters also contribute, resulting in a decline in air freshness and a greater potential for respiratory health risks.
What are Causes Indoor Air Pollution?
The lack of fresh air circulation allows contaminants, such as mold, dust, and volatile organic compounds (VOCs), to accumulate indoors. In fact, according to the American Lung Association, indoor air pollution can be two to five times worse than outdoor air pollution, a reality that is amplified during the winter months when homes become more closed off. Let’s explore the common culprits that contribute to indoor air pollution and how you can improve the air quality in your home this winter.
Dirty Furnace Filters
One of the hardest-working appliances in your home during winter months is your furnace. Have your furnace serviced yearly to ensure that it is working properly and be diligent about changing the filters every one to three months year round. The furnace can significantly contaminate your indoor air in winter for several reasons. Failing to change the filters regularly will prevent your system from trapping pollutants as it is designed to do. In addition, the restricted airflow can further contaminate the air by releasing traces of carbon monoxide into your living space from your furnace.
Clogged Vents

Dirty vents can also add to poor air quality. Forced-air heating systems may collect various pollutants within the vents, including hair, pollen, insect parts, dirt, mold, and other contaminants. And if HVAC air filters are clogged with dust, they won’t be able to work fully. With everything being sealed off and incubating from the heat in winter, this may create a cocktail of pollutants that could worsen indoor air quality, especially for those who suffer from respiratory issues such as allergies and asthma. Make sure to change all air filters regularly and clean dust from vents.
Candles
Winter is the perfect time to enjoy candles, especially those scented with fragrances such as pumpkin, apple, and pine. Although these seasonal candles enhance the ambiance, they can also contribute to poor indoor air quality. Burning candles releases fine particulate matter and soot that can accumulate indoors when ventilation is limited. Another issue is that some candles made from paraffin wax or scented candles may emit small amounts of VOCs, potentially affecting indoor air.
Mold
Another potential contaminant of your indoor air may be mold. Mold grows on damp surfaces and releases spores into the air, which can degrade indoor air quality. Moisture-rich areas, such as bathrooms and areas affected by leaks and condensation, are common problem spots. . During cold months, reduced ventilation can allow moisture and mold spores to accumulate, contributing to poor indoor air quality.
Pet Dander

Pets with fur are an adorable addition to the family, but they may not be great for your home’s air quality. Pet hairs can carry microscopic allergens known as pet dander, which consist of flakes of skin and proteins from saliva and skin oils. These tiny particles can become airborne, circulate throughout the home, and linger in the air or settle on floors, furniture, and within HVAC systems. Exposure to these allergens may lead to coughing, sneezing, watery eyes, and respiratory issues, which can trigger allergies and asthma attacks in sensitive individuals.
Dust Mites and Other Pests
Crawling pests aren’t just unpleasant to encounter, they can also impact indoor air health. One common indoor allergen source is the dust mite. Although microscopic and invisble to the naked eye, dust mites shed waste particles and body fragments that can attach to household dust. When disturbed, these particles can become airborne and trigger allergy and asthma symptoms. Cockroaches, can also contribute to air quality. Allergens in their body parts, saliva, and fecal matter can become airborne and are associated with asthma development.
A Sooty Fireplace

Your fireplace can be a factor in your home’s air quality. Wood-burning fireplaces can release particulate matter, such as soot and smoke, which may irritate the lungs and worsen existing respiratory issues. Soot, a fine black residue, can escape into the living space if the fireplace or chimney is not maintained.
Another concern is creosote buildup in the chimney. This sticky residue can restrict airflow and push pollutants back into your home. Creosote buildup may also increase the likelihood of a fire. A more serious threat from a dirty fireplace is carbon monoxide, a colorless, odorless gas produced by combustion. If ventilation is inadequate or the chimney draft is compromised, carbon monoxide could accumulate in your home, leading to flu-like symptoms or even death. Regular chimney maintenance, proper ventilation, and the presence of carbon monoxide detectors are essential for fireplace safety.
Ways to Improve Your Home’s Air Quality
You don’t have to grapple with poor indoor air quality this winter. Here are a few ways to clean the air in your home and ensure you and your family are breathing fresh air.
Open Windows Occasionally
Undoubtedly, it can get really cold in winter, sometimes dipping below freezing. While it may seem counterintuitive to open the windows and doors for a few minutes, this will help clear the air of airborne pathogens, mold, and other toxins that may be trapped in your home in winter.
Manage Moisture and Humidity
Homes can become filled with high levels of moisture in winter. Not only is it warm due to the artificial heat indoors, but heat from cooking and warm showers can increase indoor moisture levels. As the moisture increases, using the exhaust fan in the bathroom and over the range hood more frequently can help. It will vent excess moisture outdoors and help prevent the growth of mold, which could worsen indoor air quality. Exhaust fans can also be helpful in winter by removing VOCs, airborne bacteria and viruses, and other airborne particles, such as soot and pet dander. It also is helpful to use a dehumidifier in damp areas like basements.
Use an Air Purifier
Since keeping windows open during winter isn’t always ideal, another option is to incorporate a portable air purifier. Most air purifiers feature HEPA filters, which help capture microscopic particles, including bacteria, viruses, VOCs, dust mites, pet dander, mold spores, and other pollutants.
Limit the Use of Chemical Pollutants
In winter, your home is likely to be more sealed off than in other seasons to prevent cold air from entering and to retain warmth inside. While this may improve the comfort levels in your home, it drastically restricts ventilation. It’s a good idea to reduce your use of chemical pollutant, such as aerosols, paints, and certain cleaning products, to avoid trapping toxins inside and instead opt for low-VOC or VOC-free paints, finishes, and cleaners. Also avoid overuse of air fresheners and scented candless. Store chemicals outside living spaces when possible.
Keep a Regular Cleaning Regimen
It’s also importantto clean often to reduce dust, dander, allergens, and dust mites. Ensure that your cleaning regimen includes the following:
- Change filters once a month.
- Dust with damp cloths to avoid sitirring particles in the air.
- Vacuum regularly using a HEPA filter vacuum.
- Clean fireplaces regularly after use.
- Wash bedding weekly in hot water to reduce dust mites

