How Sick Building Syndrome Is Linked to Poor IAQ

A clinical and environmental exploration of how invisible air pollutants affect human health in modern buildings

Abstract

Sick Building Syndrome (SBS) refers to a condition in which occupants of a building experience acute health effects that seem linked to time spent in the building, yet no specific illness or cause can be identified. Over the past three decades, increasing evidence has pointed to indoor air quality (IAQ) as a central factor contributing to SBS. This article investigates the physiological, psychological, and architectural dimensions of the syndrome, identifies key pollutant contributors, and reviews peer-reviewed literature to understand how SBS manifests and why it continues to be underdiagnosed in both residential and commercial spaces.

1.Introduction

Why do some people feel fatigued, dizzy, congested, or cognitively impaired after spending hours inside certain buildings,  even though no pathogen or clear disease is present? This question was first systematically explored in the late 1970s and led to the identification of Sick Building Syndrome by the World Health Organization (WHO) in 1983. SBS describes a range of nonspecific symptoms, including headache, eye irritation, dry throat, mental fatigue, nausea, and skin sensitivity that improve or disappear when the affected person leaves the building. While initially considered psychosomatic or occupational stress-related, scientific research over the last two decades has shown that inadequate ventilation, accumulation of indoor pollutants, and microbial contamination play measurable roles in triggering these responses.

2. Physiological Basis and Symptomatology of Sick Building Syndrome

Sick Building Syndrome is often difficult to diagnose due to its overlapping symptoms with other conditions such as seasonal allergies, chronic fatigue syndrome, or anxiety. However, key characteristics distinguish SBS from other illnesses: symptoms are generally acute rather than chronic, tend to appear or worsen during working hours, and diminish during weekends or holidays. The physiological basis involves low-level, continuous exposure to a mixture of airborne pollutants that affect multiple systems. For example, elevated carbon dioxide levels (above 1000 ppm) are associated with reduced cerebral blood flow and impaired cognitive performance, as confirmed by Allen et al. (2016) in controlled environmental chamber studies. VOCs such as formaldehyde, commonly emitted from furniture, paints, and adhesives, can irritate mucous membranes and cause neurological symptoms even at sub-threshold levels. Particulate matter, especially PM2.5 and ultrafine particles, can penetrate deep into the lungs and enter the bloodstream, contributing to inflammation, oxidative stress, and disruption of autonomic nervous system function.

3. Building Dynamics and Air Dynamics

A critical factor in the emergence of SBS is modern building design. In an effort to reduce energy consumption, buildings have become more sealed, reducing the rate of fresh air exchange. This leads to the entrapment of pollutants, including carbon dioxide from respiration, ozone from office electronics, and chemical byproducts from cleaning agents and building materials. A 2006 study by Seppänen and Fisk found that SBS symptoms were significantly higher in buildings with ventilation rates below ASHRAE-recommended thresholds (typically 8-10 liters/second per person). Poor air circulation not only increases pollutant concentration but also creates zones of microbial growth,  especially in HVAC systems, carpets, and ceiling tiles, which serve as reservoirs for bacteria, fungi, and their metabolic byproducts, such as mycotoxins and microbial VOCs. These microbial agents have been implicated in respiratory symptoms and neurological dysfunction and are now considered likely contributors to SBS, according to recent work published in the journal Environmental Health Perspectives.

4.  Psychological and Cognitive Dimensions

SBS is not solely physiological; it also affects psychological well-being and productivity. Poor indoor air quality has been correlated with reduced memory performance, slower response times, and increased perceived stress. In one multi-location study by Satish et al. (2012), occupants exposed to increased indoor CO2 concentrations showed significant declines in decision-making performance, even when levels remained within the so-called “safe” range under most regulatory standards. These findings suggest that current IAQ guidelines may underestimate the impact of air composition on cognitive function. Furthermore, studies in school settings (Bakó-Biró et al., 2012) have demonstrated that improved ventilation directly correlates with better student performance, highlighting the cognitive toll of SBS in educational environments.

5. Underdiagnosis and Institutional Inattention

Despite its measurable impacts, SBS remains underdiagnosed in medical practice and under-addressed in architectural standards. Part of the issue lies in the diffuse nature of its symptoms and the lack of a single biomarker. Additionally, conventional indoor air quality assessments often focus on gross pollutants like PM10 or CO but overlook cumulative exposure to low-dose VOCs, microbial metabolites, and dynamic CO2 spikes due to occupancy patterns. Compounding this, building management systems rarely track real-time IAQ parameters, relying instead on static, annual inspections that miss transient air quality events. As a result, affected individuals are often left without validation or remedy, perpetuating discomfort and lost productivity in poorly ventilated or biologically unbalanced buildings.

6. Toward Ecological and Adaptive Solutions

Addressing SBS requires moving beyond symptom treatment toward environmental redesign. This includes increasing outdoor air exchange, deploying sensors to monitor IAQ in real time, and eliminating pollution sources at their origin. Yet, mechanical ventilation alone may not resolve the biological aspect of SBS. Bioaerosols,  particles of microbial or organic origin,  require more nuanced strategies such as humidity control, antimicrobial surfaces, and, increasingly, biologically active systems that restore ecological equilibrium indoors. Emerging plant-based and microbe-assisted systems offer promising approaches, not just by metabolizing airborne pollutants but by regulating humidity and outcompeting pathogenic microbes. These living systems reframe air quality not as a mechanical issue alone, but as an ecological condition requiring balance and responsiveness.

7. Conclusion

Sick Building Syndrome is a symptom of a deeper systemic failure: our buildings are no longer designed to support the biological needs of their occupants. As airtight construction, synthetic materials, and insufficient monitoring converge, air becomes stagnant, chemically complex, and biologically unstable. The resulting health effects are not imagined; they are real, measurable, and preventable. Scientific evidence now points clearly to the role of indoor air quality as a determinant of both physiological and cognitive health. Addressing SBS is not merely a matter of comfort,  it is a matter of public health, workplace performance, and long-term societal wellbeing. Restoring air quality through ecological intelligence, dynamic sensing, and biologically informed design represents a path forward toward healthier, more breathable spaces.

To explore how nature-based systems are being developed to prevent such conditions, visit: www.justbreathe.in