Sick building syndrome is a descriptive term rather than a diagnosis. It refers to a situation in which a number of people report symptoms that appear related to the time they spend in a particular building, where no single cause has been identified, and where the symptoms typically ease after they leave. It is not a disease with a defined mechanism, and it is not a finding that any measurement produces. This page sets out what the term describes, how it differs from building-related illness with an identified cause, how investigations of this kind are structured, and what the published evidence does and does not support. It is general information about buildings and is not medical advice. Anyone experiencing symptoms they associate with a building should be assessed by a doctor or an occupational health service.
The term came into use as a convenient label for a recurring situation: a proportion of the people using one building report similar symptoms, the symptoms are non-specific, no clinical signs or specific diagnosis are found, and no single agent can be identified as the cause. It describes the shape of a problem rather than its mechanism.
Because it is defined partly by the absence of an identified cause, it functions as a residual category. If an investigation identifies a specific agent and a specific condition, the label no longer applies and the situation is handled as building-related illness instead. That is worth stating plainly, because the term is sometimes used as though it named a disease with a known biology, and it does not.
It also cannot be applied to an individual. The pattern is a property of a group within a building, identified through structured enquiry across occupants, and no clinician diagnoses a person with it. An individual's symptoms are assessed clinically, on their own merits, whatever is happening in the building around them.
The symptoms usually reported are irritation of the eyes, nose or throat, dry or itchy skin, headache, tiredness and difficulty concentrating. Each of these is common in the general population and each has many ordinary explanations, which is precisely why no individual report points at a building on its own.
The feature that draws attention to a building is temporal. Symptoms begin or worsen during time spent in the building and ease after leaving it, often over an evening, a weekend or a period of leave. Where several people describe that same relationship, and where the reports cluster in a particular area, floor or zone served by one system, the pattern becomes something a building investigation can work with.
Careful enquiry establishes that pattern before anything is measured. Who reports symptoms, where they sit, at what times, on what days, and whether the symptoms follow them home are the questions that determine whether there is a building question at all, and if there is, where in the building to look first.
Building-related illness is a different category. It denotes a specific condition, arising from an identified agent in the building, with a recognised mechanism and, usually, objective clinical findings that allow a doctor to make a diagnosis. Occupational asthma or allergic responses caused by an identified sensitiser, hypersensitivity pneumonitis, and carbon monoxide exposure from a faulty combustion source are established examples. Illnesses arising from building water systems form a separate field with its own control regime.
Three things separate the two categories. Building-related illness has a named agent; the symptom pattern described above does not. It has a defined biological mechanism; the pattern does not. And it is diagnosed clinically in individuals, rather than inferred from the distribution of self-reported symptoms across a group.
The distinction changes how an investigation proceeds. Where a specific building-related condition is suspected by a clinician, the enquiry becomes targeted at a known agent, uses methods appropriate to that agent, and runs alongside clinical assessment rather than in place of it. Where no specific condition has been identified, the enquiry is broad and starts with the building services.
The consistent finding across the published literature is an association between reported symptoms and certain building characteristics. Symptom reporting tends to be higher where outdoor air supply is low, where dampness or visible mould is present, where cleaning is poor, and where thermal conditions are uncomfortable or humidity is very low. Associations have also been reported with mechanically ventilated and air-conditioned buildings compared with naturally ventilated ones.
Associations with factors that have nothing to do with air are equally consistent. Job demands, limited control over the immediate environment, dissatisfaction with lighting, noise and workspace, and the way in which building problems are communicated all correlate with symptom reporting. Any honest account of the subject has to hold both sets of findings at once.
There are real limitations in that evidence. Much of it is cross-sectional, most of it relies on self-reported symptoms collected by questionnaire, and reporting is influenced by whether occupants know an investigation is under way. Association does not establish causation, and repeated attempts to identify a single causative agent have not succeeded. The better-supported reading is that the pattern is multifactorial, with contributions that differ from building to building.
What the evidence does not provide is a threshold. No measured concentration of any parameter has been shown to mark the point at which this symptom pattern appears, and no result can therefore be used to attribute an individual's symptoms to a building or to rule the building out. What the evidence does support is that improving ventilation, correcting dampness and raising cleaning standards are the interventions most consistently associated with a reduction in reported symptoms.
Dampness and mould growth in buildings are associated with increased respiratory symptoms and with exacerbation of existing asthma. That association is the central conclusion of the World Health Organization's Guidelines for Indoor Air Quality: Dampness and Mould (2009) and is the part of the picture that is not seriously disputed.
Allergic responses are established. A proportion of people become sensitised to fungal allergens and may then experience rhinitis or asthma symptoms on exposure. Irritant effects from spores, fragments and the compounds associated with growth are also recognised. Hypersensitivity pneumonitis is a recognised though uncommon response, generally associated with heavy or repeated exposure in particular settings and diagnosed clinically.
Infection is a different matter and a narrow one. Invasive fungal infection is essentially confined to people who are significantly immunosuppressed, and it is managed by clinical services rather than through building assessment. It is not a consideration in the ordinary run of damp buildings occupied by people in normal health.
Beyond those, attribution becomes unsupported. There is no established dose-response relationship linking a spore or colony count to an individual's health outcome, so no measurement supports either reassurance or concern about a particular person. That uncertainty does not affect what should be done about a damp building: the recognised approach is to find and correct the moisture source and remove the growth, irrespective of species and irrespective of counts.
The first stage is the pattern. Structured enquiry across occupants establishes who is reporting symptoms, where they work, when symptoms occur, whether they resolve away from the building, and whether reports cluster in one area or one ventilation zone. Without that map, later measurement has nowhere sensible to point.
The second is a walkthrough. Signs of dampness, staining, condensation, odour, standing water, cleaning standards, obstructed diffusers, stored chemicals, printing and cooking areas, and reported thermal complaints are all recorded. A great many investigations find their answer at this stage.
The third is the building services, and it is the stage that most often produces the finding. Outdoor air rates, damper positions, filter grade and condition, control schedules and setpoints, humidity and temperature performance, pressure regime and commissioning records are examined. In a sealed, continuously cooled building, ventilation shortfalls are common, invisible to occupants and correctable.
Measurement comes fourth, chosen to test hypotheses formed in the earlier stages rather than as a general survey. Carbon dioxide and thermal parameters are usually first, because they are inexpensive and directly informative about ventilation. Targeted analysis follows only where a specific agent is suspected.
Two further elements matter as much as the technical work. Non-air factors, including lighting, glare, noise, workstation arrangement and workload, are recorded honestly rather than dismissed, because they influence the reports being investigated. And occupants are told what is being examined, what has been found and what will change, since an investigation conducted in silence tends to raise concern rather than settle it. After changes are made, repeating the original enquiry is the practical test of whether they helped.
A building investigation characterises a building. It does not assess people, and it produces nothing that constitutes advice to an individual about their health. No air measurement diagnoses anyone, and a favourable set of readings does not mean that a person's symptoms are imagined or unimportant.
Anyone with symptoms they associate with a building should be assessed by a doctor. Where the building is a workplace, an occupational health service can assess the individual, advise on adjustments and decide whether further clinical investigation is warranted. That route also allows a clinician to consider explanations that have nothing to do with the building, which is frequently where the answer lies.
Prompt medical advice is appropriate where symptoms persist away from the building, where breathing difficulties are involved, or where a person is known to be immunosuppressed or has a significant existing respiratory condition. In those circumstances the clinical assessment leads, and the building investigation supports it by establishing what conditions exist.
The two enquiries work best in parallel. A clinician can say what a person has; a building assessment can say what a building is doing. Neither substitutes for the other, and conclusions that cross from one to the other without evidence tend to be wrong in both directions.
Building-related illness is attributed to a named agent present in the building. The symptom pattern described by the term sick building syndrome has, by definition, no identified agent.
Building-related illness has a recognised biological mechanism. The broader symptom pattern does not, and repeated attempts to establish a single mechanism have not succeeded.
Building-related illness is diagnosed clinically in an individual. The symptom pattern is identified across a group by structured enquiry and cannot be applied to a person.
Building-related illness usually produces objective clinical findings. The reported symptoms in the broader pattern are non-specific and common in the general population.
The broader pattern is characterised by symptoms that begin or worsen in the building and ease after leaving. Building-related illness may persist regardless of location.
A suspected building-related illness is investigated for a known agent alongside clinical assessment. The broader pattern is investigated by working through the building and its services.
There is no enforceable UAE exposure limit for mould, and no published Abu Dhabi reference value for it either. Abu Dhabi's Occupational Standards and Guideline Values document (Version 3.0, 2016) carries the statement on the Abu Dhabi Public Health Centre's own page that the document is currently suspended and that entities are to comply with relevant local or federal standards in force, and it contains no fungal or bioaerosol value at all. Dubai Municipality publishes reference values for indoor air quality parameters within its Technical Guidelines for Indoor Air Quality for Healthy Life (Doc Ref DM-HSD-GU119-IAQ, Version 4, 11 December 2024). The absence of an exposure limit does not change the recognised response to a damp building, which is to identify and correct the moisture source and remove the growth.
These are the values Dubai Municipality's indoor air quality guideline sets for buildings that opt into its indoor air quality certificate. The guideline describes itself as guidance rather than as a binding standard, and the certificate route is expressly optional. They are a published reference point within a voluntary Dubai Municipality scheme, not an enforceable UAE limit.
No. It is a descriptive term for a pattern of non-specific symptoms linked to time spent in a building where no single cause has been identified. It is not diagnosed in individuals, and an individual's symptoms are assessed clinically on their own merits.
Building-related illness has an identified agent, a recognised mechanism and a clinical diagnosis, such as occupational asthma from an identified sensitiser or exposure to carbon monoxide from a faulty appliance. The broader symptom pattern has none of those.
No. There is no measurement that establishes the pattern and none that excludes it, because no threshold has been established for any parameter. Measurement is used to test specific hypotheses about the building, not to settle the question of why people feel unwell.
Dampness and mould in buildings are associated with increased respiratory symptoms and exacerbation of asthma. Allergic responses and irritation are established, and hypersensitivity pneumonitis is recognised though uncommon. Invasive infection is essentially confined to people who are significantly immunosuppressed.
Investigations most often find shortfalls in outdoor air supply, dampness, poor cleaning or uncomfortable thermal conditions, frequently in combination and alongside non-air factors such as lighting, noise and workload. A single agent is rarely identified.
A doctor. Where the building is a workplace, an occupational health service can assess the individual, advise on adjustments and decide whether further clinical investigation is needed. A building assessment characterises the building and cannot assess a person.