Why Indoor Air Quality Is Worse in Winter: 3 Key Factors

Indoor air quality is often overlooked, yet it plays a significant role in maintaining good health and well-being. During winter, the situation gets even more challenging due to the unique combination of factors affecting the air we breathe indoors.

In this article, we will examine why indoor air quality worsens during the cold season and uncover the three key factors contributing to this issue.

Why indoor air quality is worse in winter

During the winter season, indoor air quality tends to deteriorate, posing potential health risks for occupants. This decline in air quality can be attributed to several factors, such as reduced ventilation, increased use of heating systems, and limited fresh air intake.

Understanding why indoor air quality is worse in winter is crucial for individuals to take the necessary measures to maintain a healthy environment inside their homes or workplaces.

3 key factors that worsen indoor air quality in winter

1. Reduced ventilation

During the winter, people tend to keep their windows and doors tightly closed to conserve heat and energy. This lack of ventilation prevents fresh air from entering the indoor space and allows pollutants, such as dust, pet dander, and volatile organic compounds (VOCs), to accumulate. To improve ventilation, it is recommended to open windows periodically, use exhaust fans in kitchens and bathrooms, or invest in mechanical ventilation systems like heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs).

2. Increased use of heating systems

To combat the cold temperatures, heating systems are commonly used in the winter. However, these systems can contribute to poor indoor air quality if they are not properly maintained. Furnaces, boilers, and space heaters can release harmful combustion byproducts like carbon monoxide and nitrogen dioxide if they are not regularly serviced and cleaned. It is important to schedule routine maintenance for heating systems and confirm proper ventilation to prevent the buildup of these pollutants.

3. Limited fresh air intake

In winter, there is a limited supply of fresh outdoor air available for indoor spaces. As a result, indoor air can become stale and stagnant. This lack of fresh air intake can lead to an accumulation of indoor air pollutants, including allergens, dust mites, and mold spores. To address this issue, consider using air purifiers with HEPA filters to remove airborne particles or investing in indoor plants that can help improve air quality by naturally filtering pollutants.

How does cold air affect indoor air quality?

Cold air can have a significant impact on indoor air quality by trapping pollution and contributing to its deterioration. When outdoor temperatures drop during the winter season, people tend to seal their homes tightly to conserve heat. While this helps keep the indoor space warm, it also restricts the circulation of fresh air and traps pollutants inside.

Common indoor pollutants, such as dust, pet dander, pollen, and volatile organic compounds (VOCs), can accumulate and linger in stagnant air. Cold air is often drier than warm air, leading to lower humidity levels indoors. This dry environment can exacerbate respiratory issues, cause dry skin, and increase the concentration of airborne particles, making individuals more susceptible to allergies and respiratory conditions.

To mitigate the impact of cold air on indoor air quality, it is essential to strike a balance between sealing the space for warmth and allowing for proper ventilation to prevent the buildup of pollutants. Regularly opening windows or using mechanical ventilation systems can help bring in fresh air and improve overall air quality inside the home or workplace.

What role does a lack of fresh air play in indoor air pollution?

When windows and doors are kept closed to conserve heat, there is limited exchange of outdoor and indoor air. This results in the accumulation of various indoor pollutants, including dust, pet dander, mold spores, and volatile organic compounds (VOCs). Without fresh air entering the space, these pollutants become trapped and can reach higher concentrations, negatively impacting the air quality.

Inadequate ventilation hinders the removal of odors, moisture, and airborne particles, leading to a stale and stuffy environment. Lack of fresh air circulation can also contribute to increased levels of carbon dioxide (CO2) indoors, which can cause drowsiness, poor concentration, and reduced cognitive function.

To combat this issue, introduce fresh air into indoor spaces through proper ventilation methods like opening windows periodically or utilizing mechanical ventilation systems. This allows for the exchange of stale indoor air with fresh outdoor air, improving the overall indoor air quality.

In what way do heating systems influence indoor air quality?

The operation of heating systems, such as furnaces and other heating elements, can have a significant impact on indoor air quality and potentially increase indoor pollution. If these systems are not properly maintained or if there are any malfunctions, they can release harmful combustion byproducts into the air.

For instance, furnaces that burn fossil fuels like natural gas or oil may produce carbon monoxide (CO) and nitrogen dioxide (NO2) when not operating efficiently or if there is incomplete combustion. These gases are known to be toxic and can pose serious health risks, especially in poorly ventilated spaces.

In addition to combustion byproducts, heating systems can also contribute to the spread of allergens and dust particles if they are not regularly cleaned. Dust and debris can accumulate in the ducts or filters of the heating system and then be circulated throughout the indoor space.

Why is humidity important for indoor air quality?

During the winter season, cold air holds less moisture compared to warm air. As a result, indoor environments tend to become drier when outdoor temperatures drop. This lack of humidity can have several negative effects on indoor air quality.

First of all, dry air can lead to discomfort, causing dry skin, irritated eyes, and respiratory issues such as a dry throat or nasal congestion. Moreover, low humidity levels can promote the spread of airborne viruses and bacteria, potentially increasing the risk of respiratory infections. Dry air can exacerbate existing respiratory conditions like asthma or allergies. It can also contribute to the formation of static electricity and damage wooden furniture or musical instruments.

How do dust mites impact indoor air quality?

Dust mites are microscopic organisms that thrive in warm and humid environments, making our homes an ideal habitat for them. As individuals spend more time indoors, the increased shedding of dead skin cells and the presence of moisture from activities like cooking, bathing, or using humidifiers can create favorable conditions for dust mite population growth.

These tiny creatures feed on skin flakes and produce waste particles that become airborne and can trigger allergic reactions or asthma symptoms in sensitive individuals. The presence of dust mite allergens in indoor air can contribute to poor air quality, leading to respiratory discomfort, allergic reactions, and overall reduced indoor air quality.

Regular cleaning, vacuuming, washing bedding in hot water, and maintaining proper humidity levels can help reduce dust mite populations and minimize their impact on indoor air quality.

What can one do to improve indoor air quality in the winter?

• Open windows for ventilation: Despite the cold weather, periodically opening windows to let in fresh air can help improve indoor air quality.
• Use exhaust fans: Utilize exhaust fans in kitchens and bathrooms to remove pollutants and moisture from the air.
• Invest in mechanical ventilation systems: Consider installing heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs) to guarantee proper ventilation while minimizing heat loss.
• Schedule regular maintenance for heating systems. Arrange routine maintenance for furnaces and other heating systems to prevent the release of harmful combustion byproducts.
• Clean or replace filters: Regularly clean or replace filters in heating systems to prevent the circulation of dust and allergens.
• Use air purifiers: Consider using air purifiers with high-efficiency particulate air (HEPA) filters to remove airborne particles and improve indoor air quality.
• Control indoor humidity: Use humidifiers to maintain optimal humidity levels and prevent dryness, but be mindful of not creating excess moisture that could lead to mold growth.
• Keep a clean living environment: Regularly clean and vacuum your living space to minimize the accumulation of dust, pet dander, and other allergens.
• Avoid smoking indoors. Smoking indoors can introduce a significant amount of pollutants into the air. It is best to smoke outside or in designated areas away from the living space.
• Add indoor plants: Indoor plants can help naturally filter pollutants and improve air quality. Choose plants known for their air-purifying abilities, such as spider plants, peace lilies, or snake plants.

Why should I consider cracking open a window in the winter?

Cracking open a window in winter may seem counterintuitive when trying to keep the indoor space warm, but it can play a big role in improving indoor air quality. Opening a window allows for the exchange of stale indoor air with fresh outdoor air.

This influx of fresh air helps remove accumulated pollutants, such as dust, pet dander, and volatile organic compounds (VOCs), that can contribute to poor air quality. It also helps dilute and reduce the concentration of carbon dioxide (CO2) that builds up indoors. Fresh air can have a revitalizing effect, providing a sense of freshness and reducing stuffiness in the space.

While it may temporarily let in cooler air, cracking open a window for a few minutes each day can significantly enhance the overall indoor air quality and create a healthier and more comfortable living environment.

How can indoor houseplants help improve air quality?

Through a process called photosynthesis, plants absorb carbon dioxide and release oxygen, which helps increase oxygen levels in the indoor environment. Some indoor plants have the capacity to remove harmful volatile organic compounds (VOCs) from the air, such as formaldehyde, benzene, and xylene, which can come from common household items.

Plants also release moisture through a process called transpiration, which can help humidify dry indoor air. This can be particularly beneficial during the winter season, when low humidity levels are common. Not only do houseplants contribute to better air quality, but they also add a touch of greenery and aesthetics to indoor spaces, creating a calming and pleasant atmosphere.

What benefits does an air purifier bring in the winter?

Air purifiers can bring several benefits during the winter season, enhancing indoor air quality and promoting a healthier living environment. Air purifiers can effectively remove airborne particles, such as dust, pet dander, pollen, and mold spores, that tend to accumulate indoors when windows are kept closed.

This can reduce the overall allergen load and help alleviate symptoms for individuals with allergies or respiratory conditions. Air purifiers equipped with high-efficiency particulate air (HEPA) filters can capture fine particles, including bacteria and viruses, reducing the risk of respiratory infections. Air purifiers with activated carbon filters can help eliminate unpleasant odors, such as cooking smells or pet odors, that can linger during the winter when ventilation is limited.

Air purifiers can help maintain a cleaner indoor environment by trapping airborne dust and preventing it from settling on surfaces.

Why are energy-recovery ventilators significant for good air quality?

Energy-recovery ventilators (ERVs) play a significant role in maintaining good indoor air quality, particularly during the winter season. These ventilation systems are designed to bring in fresh outdoor air while simultaneously recovering heat or coolness from the exhaust air, resulting in energy efficiency.

ERVs help address the challenge of limited fresh air intake during the winter by providing a controlled and balanced exchange of stale indoor air with fresh outdoor air. This exchange helps remove accumulated pollutants, moisture, and odors from indoor spaces, reducing the risk of indoor air pollution. ERVs help regulate humidity levels by transferring moisture between the incoming and outgoing air streams, preventing excessively dry or humid conditions.

How does changing filters regularly contribute to better air quality?

Filters are designed to trap and remove airborne particles such as dust, pollen, pet dander, and other pollutants. Over time, these filters can become clogged and less effective at capturing these particles, allowing them to circulate back into the air.

By regularly changing filters as recommended by the manufacturer, you ensure that your HVAC or purifier system can continue operating at its optimal efficiency. This helps to remove a significant amount of pollutants from the air, reducing the overall allergen load and improving the quality of the air you breathe. Clean filters also help to maintain proper airflow, preventing strain on the system and promoting better ventilation throughout your home or office.