Dr. Stephanie Taylor

July 18th, 2025

How Indoor Air Particles Are Impacting Our Health

Recent research has linked exposure to airborne particulate matter with the development of serious health issues, including respiratory diseases, cardiovascular conditions, immune system disruption, and even cancer. Now, the focus has narrowed on the role of fine and ultrafine particles, particularly those we breathe indoors, with both acute and chronic illness.

Connecting Fine Indoor Air Particles With Disease

Of all air pollutants, fine particulate matter (PM2.5 and smaller) poses the most widespread risk to our health. The World Health Organization (WHO) estimates that air pollution caused over 7 million deaths worldwide in 2012, with fine particulate matter playing a leading role.

Fine particulate matter is able to:

• Penetrate deep into the lungs, leading to asthma, chronic obstructive pulmonary disease (COPD), and lung cancer
• Trigger heart attacks and arrhythmias by entering the bloodstream
• Contribute to inflammatory bowel disease and digestive complications

Fine particulate matter is also classified as a Group 1 carcinogen by the World Health Organization. Its ability to penetrate deep into the lungs and enter the bloodstream make it especially dangerous. It’s become clear that people must protect themselves from these airborne particles, but with people spending most of their time in shared spaces, building professionals now assume a vital public health role.

Building Professionals Now Play a Public Health Role

With people spending approximately 90% of their time indoors, much of it in offices, schools, and commercial buildings, conversations about health risks linked to air quality are no longer limited to medical professionals. Today, questions once posed to pulmonologists are surfacing in boardrooms and facilities meetings, reflecting a growing awareness that indoor environments now play a critical role in public health.

Yet, despite this shift, many building ventilation and filtration strategies are still based on an outdated methodology: outdoor air pollution data. While helpful as a starting point, this approach often overlooks the unique and often more concentrated exposure risks that exist inside buildings, especially those with high occupancy, limited ventilation, or aging infrastructure. Indoor particulate matter levels can spike in a variety of ways, ranging from everyday activities such as cooking, cleaning, and operating office equipment, or from other sources like outdoor pollution seeping in from traffic or wildfires, or poorly maintained HVAC systems.

To effectively safeguard indoor air quality (IAQ), facility managers must recognize the wide range of indoor pollutant sources and implement data-driven strategies tailored to their specific environments. This begins with rethinking the very foundation of building ventilation, because updated HVAC parameters are now essential for protecting occupant health.

Updated HVAC Parameters are Needed

Research in air toxicology has demonstrated that indoor and outdoor air pollutant levels can differ significantly, often depending on the specific pollutant, building type, occupancy levels, and variations in temperature and humidity between indoor and outdoor environments. This means that a one-size-fits-all approach to HVAC design, based solely on outdoor air quality data, is insufficient.

To accurately assess and manage indoor air quality, HVAC systems must be informed by real-time, location-specific data that captures both indoor and outdoor particulate matter levels. However, current HVAC design standards for filtration efficiency and ventilation rates still rely heavily on historical outdoor air monitoring, which overlooks the more immediate and prolonged exposures that occur inside buildings.

Given that people spend the majority of their lives indoors, the indoor environment represents the most critical area of exposure. This calls for an urgent update to HVAC design parameters, ones that integrate continuous indoor air quality monitoring and account for indoor pollutant sources, occupant behavior, and building performance over time.

Tools like the ThinkLite Air Health Index can help bridge this gap by providing a simplified, real-time score that reflects the true impact of air quality on human health. By incorporating such health-focused metrics into building operations, facility managers and HVAC professionals can expand beyond basic compliance to more informed decision-making that actively supports occupant health.