Winter is upon us. The days are shorter and the nights are longer. As the temperatures drop and the snow falls, we seek the warmth of indoors. 

However, as we retreat indoors this winter, it’s important to remember that our homes may not be the sanctuaries we imagine. Indoor air can be two – five times more polluted than outdoor air. This is especially true during the winter months when we seal up our homes to conserve heat, trapping pollutants like mold, dust, particulate matter, and volatile organic compounds (VOCs) inside. 

Before heading indoors for the long winter, let’s look at some of the key sources of indoor air pollution and what you can do to improve the air you breathe at home this winter. 

Space Heaters

Whether your power goes out or you are just in need of some extra heat, natural gas and kerosene space heaters may seem like an obvious solution, but they can cause sickness and even death. 

  • The Problem: Anytime we burn anything – including natural gas or kerosene – it creates combustion by-products, including carbon monoxide and nitrogen dioxide. These toxic gases can cause headaches, nausea, confusion and lung irritation, and can be fatal at high levels. Fuel-burning heaters that are vented to the outside are much safer to use than unvented ones. These heaters also pose a fire risk.  
  • The Solution: Opt for electric space heaters. If you lose power, run a generator outdoors to power your home. If you must use a portable kerosene or unvented gas heater, have the units inspected and serviced annually, do not use for extended periods of time and install a carbon monoxide detector and fire alarm. For kerosene heaters, only use grade K-1 kerosene. 

Wood-burning Stoves and Fireplaces

Nothing evokes the essence of winter more than cozying up in front of a warm, crackling fire, but for most households, they are merely an aesthetic indoor air polluter.  

  • The Problem: Emissions from wood smoke can contain harmful pollutants, including particulate matter, carbon monoxide, nitrogen oxides and volatile organic compounds. Wood smoke can cause coughing, wheezing, asthma attacks, heart attacks and premature death. A proper fire is one that burns hot and puts off minimal smoke, but improper installation, maintenance and usage can cause problems.  
  • The Solution: Unless it is your primary heat source, it is best not to use wood-burning stoves and fireplaces. Do not use the fireplace or stove if it is not properly vented to the outside.  If you must use them, be sure to service your units annually to ensure they are in proper working order. Only use seasoned firewood – that is, wood that has been cut and dried for 6+ months – and newspaper or dry kindling. If you have an older wood-burning stove, consider replacing it with an EPA-certified wood stove which are verified to emit minimal particulate matter. Run a portable air cleaner when burning to reduce levels of pollutants in the air.  

Volatile Organic Compounds (VOCs)

VOCs are chemicals that vaporize at room temperature and can cause a variety of health problems including cancer.  

  • The Problem: VOC concentrations during winter months can be elevated because we are spending more time indoors and we are not opening doors and windows as much. We may also be making VOC levels worse by the things we do in the winter, like using scented candles, wood-burning fireplaces, and various cleaning products. Breathing VOCs can irritate the eyes, nose and throat, can cause difficulty breathing and nausea, and can damage the central nervous system and other organs. Some VOCs can cause cancer.  
  • The Solution: Reduce the amount of VOCs you introduce into your home – opting for safer, less toxic cleaning and personal care products. Increase ventilation if you can by opening your windows if you are using high-VOC products. Opening your windows for five minutes every day can help to reduce the overall VOC levels in your home, but should be avoided on days in when outdoor pollution levels are high. Hold off on home renovations like installing carpets until the spring when you can keep your windows open for extended periods of time. Refrain from the use of essential oils and diffusers.

Moisture and Mold

Balancing the correct amount of indoor air moisture can be a delicate dance – too little moisture, the air is dry and we start to experience airway irritation, dry eyes and dry skin, but too much moisture can support the growth of biological pollutants like dust mites and mold

  • The Problem: Excess moisture in the home comes from many sources including water leaks and condensation on windows or pipes, as well as from activities like bathing and cooking. All living things also breathe out moisture. When moisture is permitted to accumulate in the home, it creates a perfect habitat for mold to grow. When airborne mold is breathed in, it can irritate the eyes, skin, nose, throat and lungs. It can also trigger allergic reactions and asthma symptoms in people who are allergic to mold.
  • The Solution: Maintain your home’s humidity level between 30-50% to prevent the growth of mold and mildew but is comfortable for occupants. Prevent moisture from accumulating by addressing water leaks immediately. Wipe down condensation on windows and other areas where water collects. Run the bathroom exhaust fan during and 30 minutes after bathing. When cooking, cover pots when cooking and use the exhaust fan above the stove. If your home’s humidity is above 50%, work to increase air circulation by placing fans around the home. Move furniture 1-2 inches away from walls. Use a dehumidifier to draw moisture from the air. 

By taking steps to address these indoor air pollutants, we can transform our homes into havens of clean, healthy air, allowing us to fully embrace the cozy comforts of winter without compromising our well-being.

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