Sick Building Syndrome Explained

When Buildings Make Occupants Sick

The term “sick building syndrome” is a misnomer. After all, it’s not the building that is sick, but rather its occupants who feel sick because of the building.

With respect to SBS, there are more questions than answers. It’s very hard to test SBS in experiments. First, the physical effects of SBS vary widely from person to person and are subjective. Second, it’s hard to pin down a cause of SBS—dampness, chemical exposure, and inadequate ventilation have all been implicated. Third, there’s no agreed-upon way to “diagnose” a building. Fourth, buildings themselves are, by nature, uncontrolled environments that are difficult and costly to test in large numbers.

Woman holding her head at her desk
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Various mucosal, skin, and respiratory symptoms have been reported with SBS, including the following:

  • Itchy and watery eyes
  • Runny nose
  • Dry and itchy skin
  • Stuffy nose
  • Sinus infection
  • Dizziness
  • Headache (dull, non-throbbing, non-migrainous, “pressure” in the head)
  • Nausea
  • Fatigue
  • Problems with concentration
  • Cough

These symptoms are experienced while a person is in the offending building, and upon leaving, most of these symptoms should remit, only to begin again once a person returns to the building. Buildings that elicit SBS include workplaces, schools, hospitals, care homes, and homes.

Although two people exposed to the same building can experience different symptoms, surveys have demonstrated symptom patterns among respondents representing several different countries.

Notably, homes as a general cause of SBS have been studied in Sweden. Specifically, Swedish researchers have focused on water damage and ventilation as precipitators. Furthermore, Swedish studies have also pointed to home insulation as a possible contributor to sick building syndrome.

Here are factors associated with SBS:

  • Cigarette smoke
  • Paper dust
  • Office dust
  • Exposure to computer screens
  • Air-conditioning
  • Low fresh-air ventilation in air-conditioned buildings
  • Little control of lighting and temperature
  • Warm environments (greater than 73 degrees Fahrenheit)
  • Poor service maintenance of the building
  • Water damage
  • Insulation
  • Unclean environments

Research shows that women, smokers, and those with allergies (i.e., atopy) are more likely to experience SBS. People with more menial positions in the occupational hierarchy of the office are also more likely to experience SBS. Of note, people with more menial positions in the office often spend more time sitting in front of computers.

People who complain of SBS often work in offices that meet current standards for design, temperature, ventilation, and lighting. For the most part, naturally ventilated buildings with limited temperature control have been shown to have fewer occupants who complain of SBS.

The Occupational Health and Safety Organizations (OSHA) recognizes sick building syndrome as attributable to poor indoor air quality.

The Environmental Protection Agency (EPA) defines SBS as the following:

"The term "sick building syndrome" (SBS) is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The complaints may be localized in a particular room or zone, or may be widespread throughout the building."

In 1984, the WHO estimated that globally up to 30% of buildings of new and remodeled buildings may have poor indoor air quality contributing to SBS. Problems with indoor air quality may be either temporary or long-term. Poor indoor air quality can be secondary to poor building design or the activities of occupants. Additionally, when a building is used in a manner counter to the original design—for instance, a retail unit used for manufacturing—then issues with indoor air quality may arise.


Humidity has been hypothesized as a chief contributor to SBS. In warmer climates, too much indoor humidity has been linked to SBS. Furthermore, the use of humidifiers in warm, damp environments has also been linked to SBS. In Scandinavia, where the humidity can dip below 10% in the winter months, there is some evidence that using a humidifier may be linked to a lower prevalence of SBS. Thus, it seems that in environments with moderate levels of humidity, occupants tend to complain less of SBS.

Some experts hypothesize that air conditioning units which contain humidifiers can serve as reservoirs for microbial growth. Conversely, the reservoirs located in dehumidifiers, which pull water from the air, have also been implicated in microbial growth. Moreover, ceiling air-conditioning units are often located in the ceiling above office space where maintenance is difficult—further contributing to the risk for SBS secondary to microbial growth.

However, the idea that bacteria or fungi could somehow contribute to SBS is contentious. Some experts believe that mold can cause systemic infection only in people with compromised immune systems. In people who are otherwise healthy, mold wouldn’t cause illness.

In a 2017 article titled “Mold and Human Health: a Reality Check,” Borchers and co-authors write that “there is no scientific evidence that exposure to visible black mold in apartments and buildings can lead to the vague and subjective symptoms of memory loss, inability to focus, fatigue, and headaches.”

In another 2017 study, Swedish researchers found that 40% of single-family homes had water damage to the foundation, which was linked to SBS. Furthermore, 23% of survey respondents reported recent SBS symptoms.

Interestingly, the Swedish researchers found that buildings with a low thermal transmittance value—or buildings that were energy-efficient—had fewer occupants who complained of SBS symptoms. More commonly, it's been suggested that energy-efficient constructions would result in poorer indoor air quality.


Many experts blame SBS on poor indoor air quality and inadequate ventilation.

Between 1900 and 1950, ventilation standards for buildings called for about 15 cubic feet of outside air per minute delivered to each building occupant. This higher ventilation rate was needed to remove body odors and unpleasant smells.

In the wake of the 1973 oil embargo, energy conservation measures were taken, and to save on energy, only 5 cubic feet of outside air per minute for each building occupant was recommended. It’s hypothesized that these decreased levels of ventilation were unhealthy and made occupants uncomfortable. This problem was compounded by air-conditioning and heating systems, which failed to distribute fresh air to people inside more energy-efficient buildings.

In recent years, experts have once again recommended that higher levels of air ventilation be provided to building occupants. For instance, office occupants should receive a minimum of 20 cubic feet of outside air per minute per occupant. Furthermore, 15 cubic feet per minute of ventilation is considered a minimum for all buildings, with certain environments, such as indoor smoking areas, requiring up to 60 cubic feet per minute.

It’s hypothesized that higher levels of air ventilation could decrease the risk for SBS symptoms. Results from research testing this hypothesis, however, have been mixed. Some studies have shown that increased ventilation rates decrease SBS symptoms among office workers, and other studies have demonstrated no change.

One problem with many earlier experiments examining the effect of increased ventilation on SBS prevalence is that these studies used air-conditioning units already present in buildings to increase ventilation. The air-conditioning units could be polluted thus confounding results.

More recent research suggests that about half the air in a building should be exchanged per hour to minimize symptoms of SBS. Furthermore, ventilation units should be maintained regularly and minimize pressure differences in enveloping structures to deter harmful pollutants from entering the building.


Sick building syndrome is not formally recognized as an evidence-based diagnosis; hence, there’s no evidence-based treatment. Nevertheless, it’s recognized as a condition by OSHA, the EPA, and other organizations. Furthermore, the NHS, or national healthcare system in the United Kingdom, does make certain recommendations on how to deal with sick building syndrome.

Here are some recommendations made by various organizations regarding SBS:

  • Regulate the temperature and humidity levels.
  • Check the cleanliness of the building.
  • Check that cleaning materials are safe and stored properly.
  • Check all air humidifiers, air filters, and cooling towers.
  • Open windows to ensure ventilation.
  • Take regular screen breaks.
  • Go outside and walk around during breaks.
  • Maintain good posture at work.

One obvious cure for sick building syndrome is to avoid the offending building altogether. However, because most people need their jobs—and their beds—this solution is often times unfeasible.

A Word From Verywell

Although the existence of sick building syndrome is often called into question, enough people have complained of building-related discomfort and symptoms that it’s hard to ignore the reality that something is going on.

Right now, because we don’t exactly know what causes sick building syndrome, it’s hard to fix the problem. Many experts point to air ventilation as a cause; thus, it’s a good idea to ensure that all buildings are adequately ventilated. Furthermore, humidity likely plays a role, and environments shouldn’t be too damp or too dry. Additionally, if you live in an already humid environment, it's best to avoid using a humidifier.

Many physicians dismiss sick building syndrome as a trivial complaint. Sick building syndrome is often regarded as a pseudo diagnosis, with nonspecific symptoms and no objective signs or biological markers.

If more than 20% of a building’s occupants experience SBS symptoms, the building is labeled a “sick building.” If you suspect that you work in a sick building, it’s a good idea to speak with other occupants to see whether they are experiencing symptoms, too. Furthermore, document your concerns (i.e., take pictures of water damage and unclean environments) and approach management. Because sick buildings are often up to code, management may dismiss these concerns. In these cases, it may be a good idea to contact OSHA or the EPA for an air-quality investigation.

In addition to calling attention to the problem, it’s a good idea to protect yourself while working in a sick building. To minimize symptoms, you should try to get plenty of fresh air and do your best to maintain a clean environment and minimize screen time, which is linked to SBS. Because there’s a big overlap between allergies and sick building syndrome, it’s probably a good idea to make an appointment to see an allergist for further evaluation.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Borchers, AT, Chang, C, Gershwin, EM. Mold and Human Health: a Reality Check. Clinic Rev Allerg Immunol. 2017; 52:305–322.
  • Burge, PS. Sick Building Syndrome. Occupational and Environmental Medicine. 2004; 61:185–190.
  • EPA. Indoor Air Facts No. 4 (revised) Sick Building Syndrome. www.
  • NHS Choices. Sick Building Syndrome.
  • Smedje, G, et al. SBS symptoms in relation to dampness and ventilation in inspected single‑family houses in Sweden. International Archives of Occupational and Environmental Health. June 17, 2017.

By Naveed Saleh, MD, MS
Naveed Saleh, MD, MS, is a medical writer and editor covering new treatments and trending health news.