Does Cold Weather Affect Indoor Air Quality?

During the wintertime, air quality and pollution levels can be affected. But how is air pollution affected by weather? Some types of pollution are worse in the summer heat, while others are worse in cold winter weather. The same atmospheric conditions that create weather also affect air quality. Air leaks, cold drafts and condensation are never good signs when it comes to saving money and staying warm this season. However, having a tightly sealed, energy efficient home can lead to a decrease in air circulation and a reduction of fresh air.

So, does cold weather affect indoor air quality? The short answer is yes.

What is Indoor Air Quality?

According to the EPA, Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Understanding and controlling common pollutants indoors can help reduce your risk of indoor health concerns.

Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.


  • Immediate Effects

Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person’s exposure to the source of the pollution, if it can be identified. Soon after exposure to some indoor air pollutants, symptoms of some diseases such as asthma may show up, be aggravated or worsened.

The likelihood of immediate reactions to indoor air pollutants depends on several factors including age and preexisting medical conditions. In some cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological or chemical pollutants after repeated or high level exposures.

Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from the area, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air coming indoors or from the heating, cooling or humidity conditions prevalent indoors.

  • Long-Term Effects

Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.

While pollutants commonly found in indoor air can cause many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time.


Ways Weather Can Affect Indoor Air Quality (IAQ):

Several elements influence air quality. The wind determines the dispersion of air pollutants and rain helps to significantly reduce the concentrations of pollutants in the air we breathe. Conversely, a high-pressure situation with stagnant air masses leads to an increase in the concentration of pollutants. This is the phenomenon that occurs during the cold and dry weather of winter. It then produces air pollution peaks.

  • Cold Weather

When the weather is cold, we will notice that the exhaust from vehicles, chimneys, and smokestacks is more visible. This is caused by more pollutants in the air as well as the warm vapor exhaust becoming more visible. Typically, warm rising air near the ground lifts pollution away. However, during the winter, the layer of warm air acts like a lid, keeping cold air at the surface. This creates a thermal inversion, which forms when a layer of warm air above traps cool air and pollution close to the ground.

  • Wind and Air Pressure

Because air is almost always on the move, air pollution is easily transported from one area to another. Low-pressure systems bring wet and windy conditions. A passing storm front can wash pollutants out of the atmosphere or transport them to a new area, producing clear skies. It is important to note that the pollutants are not really gone — rather, they have been moved to a new location.

The opposite is true of high-pressure systems, which can create stagnant air. When the air stops moving, pollutants such as vehicle and factory exhaust concentrate over an area.


  • Too Much Insulation

Can you over-insulate your home? There is certainly a point where insulation does more harm than good. Too much insulation means moisture is trapped inside and there is not enough fresh air moving through the space.

Modern construction is geared toward sealing homes as much as possible in an effort to stay warm throughout the cold weather, reduce heating costs and better serve the environment. While this is great for energy-efficiency purposes, these efforts can make it difficult for allergens, molds and fungi to exit the home. Instead, they grow quickly inside the house, which can be damaging to those living there.


  • Increase in Pollutants

As temperatures drop, we spend more time indoors, meaning that we are breathing in surrounding pollutants more often. Also, with less open doors and windows to ventilate the space, there are simply more pollutants present. In the winter, pets are also inside more which means increased allergens and pet dander.

Candles and certain fireplaces are other sources of worsened indoor air pollution. When they burn, many emit VOCs, which are dangerous to breathe in. Overall, there are quite a few winter activities and daily practices that hurt air quality.

Poor indoor air quality can cause headaches and fatigue, and allergy symptoms such as itchy eyes and throat. Respiratory problems such as asthma can also be exacerbated by exposure to indoor pollution even after a short time.

Due to a lack of fresh air and an increase of time spent in the home, many homes will become saturated with indoor allergens and pollutants in the wintertime, such as:

  • Mold
  • Pet dander
  • Dead skin
  • Dust mites
  • Pollen


  • Heating

The winter season is also a time when the house is heated and it is a major source of pollutant emissions, especially in the case of residential wood heating. It is therefore important to ensure that your heating system complies with environmental standards. If it does not, it is crucial that you modernize your heating system.

  • Temperature, Sunlight and Humidity

Air temperature affects the movement of air, and thus the movement of air pollution. Because energy from the Sun is absorbed by the Earth’s surface, air near the ground is warmer than air that is farther up in the troposphere. The warmer, lighter air at the surface rises, and the cooler, heavier air in the upper troposphere sinks. This is known as convection and it moves pollutants from the ground to higher altitudes.

Cold air cannot hold much water vapor, and the colder the air, the drier it is. Heating the indoor air only makes the air drier, and the result is low indoor humidity levels. This can cause:

  • Dry skin
  • Static electricity
  • Nose bleeds
  • Brittle furniture or belongings
  • Squeaky hardwood floors

It is important to maintain the humidity at a level that is not so low as to cause damage and discomfort, but is not so high as to create moisture problems inside the home. If outdoor temperatures are between 10 to 20 degrees, humidity indoors should not exceed 35 percent. The higher the outdoor temperature, the higher the indoor humidity should be.

A humidifier can be used to increase indoor humidity levels. These devices come in all different shapes, sizes and prices, and work by emitting water vapor thus increasing moisture in the room.

Improving Air Quality

  • Monitor and Track Indoor Air Quality

An air quality monitor provides valuable data to help you better understand the quality of your air and how it changes over time. These devices provide real-time information, allowing homeowners to determine exactly what worsens and benefits their air quality.

  • Clear Air Paths for Grilles, Registers and Diffusers

Make sure the air vents in the space are clean, rust-free and able to open and close. This includes grilles, registers and diffusers throughout your home. Make sure carpets and furniture are moved away to help air properly circulate and filter in each room. Winter is not the time to be unprepared. This is especially true when it comes to the HVAC system you and your family will rely on. Choose to make upgrades early on in the season.


  • Upgraded Air Filtration for Homes

Filtration is the number one way to improve air quality as it is the easiest and cheapest method. You can learn more about how air filters actually work and try to remember the last time your space upgraded filters. Changing air filters is often an afterthought for homeowners. Instead, set a schedule to change filters on a regular basis. That way, occupants are breathing only the cleanest air possible this winter.


  • Air Purification Systems

Upgrading to an active air purification system not only makes filtration and ventilation more efficient, they actively clean the air and surfaces in your home. Purifiers release “scrubbers” to create cleaner air to every corner of the room. A whole-home air purification system greatly reduces (or even eliminates) mold, pet dander, dust mites, VOCs and more indoor pollutants.


  • Easy Habits for Better Air Quality

Developing healthy habits that ensure cleaner air quality are simple. When cooking, turn on the fan above your stovetop. During and after a shower, flip on the fan in the bathroom. Even ceiling fans help circulate air a bit more. Also, stay on top of potential mold in your home. If you start to see any issues, such as a musty smell or black spots in the corners, call a professional to assess and treat the situation before your family is inhaling toxic air.

Also consider switching from bleach and other harsh cleaning chemicals to white vinegar and essential oils. These are not as bad for air quality. Just be sure that if you have pets, you select essential oils that are safe to use around them!


Final Thoughts

The more you know about the sources of indoor air pollution the better your chances are of managing and limiting the amount of harmful toxins and pollutants in your everyday living and working spaces. Increasing airflow in the kitchen, sealing gaps in doorways, windows and entryways, regularly cleaning, controlling humidity levels and installing purifiers that automatically purifies and humidifier for a healthier environment can all be valuable steps towards improving your indoor air quality.

If your system needs repair or inspection before winter, call us at 951-926-1002. You can also visit our Contact page and complete the contact form.