The Invisible Dilemma: Why Indoor Air Quality is Oftentimes Worse Than Outdoor Air Quality

In an increasingly urbanized world, people are spending more time indoors than ever before. From homes to offices and commercial spaces, we find ourselves sheltered from the elements. While it might seem like a protective cocoon, the reality is that the air we breathe indoors is often more polluted than the air outside. Indoor air quality (IAQ) is a pressing concern that demands our attention.


What Are Reasons for Poor Indoor Air Quality?

Limited Ventilation: One of the primary reasons for poor indoor air quality is inadequate ventilation. In an effort to improve energy efficiency, modern buildings are designed to be airtight, limiting natural airflow. As a result, pollutants generated indoors, such as cooking fumes, cleaning chemicals, and volatile organic compounds (VOCs) from furniture and paints, get trapped, leading to a buildup of harmful substances.[1]

High Pollutant Concentration: Indoor environments harbor a wide range of pollutants, including allergens, dust mites, pet dander, and mold spores. Additionally, volatile organic compounds (VOCs), emitted from household products like paints, cleaning agents, and furniture, or as component of building materials like plywood, carpets and insulation can accumulate over time and significantly degrade indoor air quality.[2]

Inadequate Filtration: While outdoor air is exposed to natural filtering processes like wind, precipitation and plants, indoor spaces often rely on ventilation systems that may not effectively filter out pollutants. Inefficient or neglected HVAC systems can circulate contaminants throughout the building, exacerbating the problem. Extreme weather conditions, such as high heat or cold, can lead people to seal their indoor spaces even more tightly. This intensifies the problem of inadequate ventilation, as indoor air is continually recirculated without being refreshed.[3]

Human Activities: The mere presence of humans indoors can negatively impact air quality. Activities like cooking, cleaning and even breathing release moisture and pollutants into the air. Overcrowded spaces can further amplify these effects, leading to increased carbon dioxide levels and a decrease in oxygen.[4]

Discover the main concerns in the workplace in this infographic.



What Can I Do to Improve Indoor Air Quality?

It is essential to address indoor air quality proactively to help safeguard our health and well-being. Here are some strategies listed below that can help lead to a better indoor air quality:

Source Control: This is the most effective way to improve air quality in buildings. Start by addressing the root causes of indoor air pollutants. Identify and mitigate potential sources of contamination, such as using eco-friendly cleaning products or reducing tobacco smoke indoors.[5]

IAQ monitors such as the AirAssure™ Indoor Air Quality Monitor equips you to track levels of particulate matter (PM), traditional IAQ parameters and up to six gases. This helps to continually verify the health of your air and keep you well ahead of indoor environmental contaminants.

With the TSI VelociCalc® 9600 Series Multi-Function Ventilation Meter, professionals can use a versatile and portable solution for measuring air velocity and determine a building’s ventilation effectiveness.

Improved Ventilation: Proper ventilation is essential for bringing fresh outdoor air into indoor spaces and helps reducing indoor airborne pollutants coming from indoor sources. The Environmental Protection Agency (EPA) suggests a dual approach: Opening windows when weather conditions permit and strategically utilizing exhaust fans. By ensuring proper air circulation, occupants can effectively reduce the concentration of indoor pollutants and create a more healthful living environment.[6]

Air Cleaning: The EPA also recommends the use of air purifiers equipped with HEPA filters to effectively remove particles, allergens, and contaminants from the air. This is particularly beneficial for individuals with respiratory conditions or those living in areas with poor outdoor air quality.[7]


In conclusion, the disparity between indoor and outdoor air quality is a significant environmental and public health concern. Understanding the causes of indoor air pollution and implementing measures to address them can help us create healthier living and working environments for a healthier future.

Lean more about TSI IAQ solutions