Sick building syndrome (SBS) is a condition where people develop symptoms like headaches, fatigue, and eye or throat irritation that are directly tied to time spent in a particular building. The hallmark feature is timing: symptoms appear while you’re inside the building and resolve within minutes to hours after you leave. It’s not caused by a single identifiable illness, which is what makes it distinct from other building-related health problems.
Common Symptoms
The most frequent pattern involves irritation of the mucous membranes in the eyes, nose, and throat. People report stinging or watery eyes, a stuffy or runny nose, and a scratchy throat that clears up once they go home. Headaches and unusual tiredness or fatigue are also core complaints. Less commonly, people experience dry or itchy skin.
What ties these symptoms together isn’t their severity but their consistency. They follow a predictable schedule, worsening during the workday and improving on evenings and weekends. In a building with SBS, multiple occupants typically report the same complaints at the same time, which distinguishes the problem from individual allergies or personal health issues. The symptoms are subjective and reversible, meaning they don’t show up on lab tests or imaging, and they don’t cause lasting damage.
What Causes It
There’s rarely a single culprit. SBS typically results from a combination of factors acting together inside the building. The most commonly implicated issues fall into a few broad categories.
Poor ventilation is the most frequent contributor. Buildings designed to be energy-efficient sometimes restrict fresh air intake to the point where indoor pollutants accumulate faster than they’re removed. When heating, ventilation, and air conditioning (HVAC) systems are poorly maintained or undersized for the number of occupants, indoor air quality drops.
Chemical contaminants come from sources you might not expect. Carpeting, adhesives, upholstery, manufactured wood products, and cleaning supplies all release volatile organic compounds (VOCs) into indoor air. Copy machines and printers contribute their own emissions. These chemicals individually may be present at low levels, but together they can create a combined exposure that triggers symptoms.
Biological contaminants like mold, bacteria, and pollen thrive in areas with excess moisture. Stagnant water in HVAC drain pans, water-damaged ceiling tiles, and damp carpet all become breeding grounds. Even dust buildup in ductwork can harbor biological material that gets circulated throughout a building every time the system runs.
Environmental comfort factors round out the picture. Inadequate temperature control, poor humidity levels, flickering or harsh lighting, and persistent noise all contribute to SBS complaints. These aren’t air quality problems in the traditional sense, but they compound the discomfort and make occupants more sensitive to other irritants.
SBS vs. Building-Related Illness
The distinction matters because the two problems look similar on the surface but differ in seriousness. Sick building syndrome is characterized by its subjective, reversible nature. You feel lousy in the building, you feel fine when you leave, and a doctor can’t pin your symptoms on a specific diagnosis.
Building-related illness (BRI) is a more medically serious category. It includes conditions like asthma, hypersensitivity pneumonitis (a type of lung inflammation from inhaling certain particles), sinus infections, and inhalation fevers. These illnesses are less common than SBS, but they produce measurable clinical findings, may require prolonged recovery, and can cause substantial health problems even after you leave the building. BRI cases typically point to a specific contaminant or pathogen that can be identified and tested for.
SBS is far more prevalent. Studies across North America and Europe have found it widespread in nonindustrial buildings, particularly offices. BRI, while rarer, demands more urgent investigation because the health consequences are harder to reverse.
How Buildings Get Fixed
Remediation ranges from simple housekeeping changes to full HVAC renovation, depending on the source of the problem. Many solutions are less extensive than people expect.
- HVAC maintenance: Replacing dirty filters, cleaning ductwork, and ensuring the system delivers adequate fresh air are first-line fixes. These steps alone resolve a significant share of complaints.
- Moisture control: Water-damaged areas need to be dried within 48 hours to prevent mold growth. Portable dehumidifiers, cleaning window air conditioning units, and fixing leaks promptly all reduce biological contaminants.
- Source removal: Replacing carpet with tile, swapping out old furniture that off-gases chemicals, and switching to low-VOC cleaning products eliminate pollutants at their origin rather than trying to filter them out of the air.
- Housekeeping: Regular cleaning of surfaces, removal of visible contaminants, and keeping personal workspaces tidy reduce the reservoir of dust and biological material that HVAC systems recirculate.
Prevention is more effective than remediation. Timely maintenance of HVAC systems, rapid response to any water intrusion, and consistent housekeeping prevent most indoor air quality problems before symptoms ever develop.
Who Is Most Affected
SBS disproportionately affects office workers in large, sealed buildings where windows don’t open and ventilation is entirely mechanical. The problem became widely recognized in the 1970s and 1980s as energy conservation measures led to tighter building envelopes with reduced outdoor air circulation. Modern green building standards have improved ventilation requirements, but older commercial buildings remain vulnerable, especially those that haven’t had HVAC upgrades.
Individual susceptibility varies. People with pre-existing allergies, asthma, or skin sensitivities often notice symptoms sooner and more intensely than their coworkers. But when a building genuinely has SBS issues, the complaint rate across all occupants tends to be high, which is one of the clearest signals that the building itself is the problem rather than individual health conditions.
If your symptoms consistently improve on days you’re away from a particular building and worsen when you return, that temporal pattern is the most reliable clue that the building environment is involved. Tracking when symptoms start, peak, and resolve can help identify the connection and make the case for an indoor air quality investigation.