How can a building become sick?
Buildings that apparently make people sick are of considerable concern both to inhabitants and also local authorities. Often the causes of symptoms remain obscure and in addition many basic pieces of information on these phenomena are missing. Groups of people selected by random sampling may provide information on population exposures, but this is not applicable to situations where the exposures are very high because of a structural problem in the building or because of human activities.
The term sick building usually denotes a building where people have exceptionally high rates of different allergy-like, respiratory, or neurological symptoms, or sick leaves, but no logical common denominator can be found to explain why they occur. Thus also any attempts to correct the situation and repair the building are very difficult, and the outcome of the repair is uncertain to say the least.
Sick building syndrome (SBS)
Indoor air problems causing irritation to the mucous membranes and fatigue-like general symptoms may be traced to chemical exposure via indoor air. They are often called the sick building syndrome. There can be several causes e.g. disintegration of plastic floor covering caused by moisture damage, evaporation of components of paints, glues or lacquers from furniture and other surfaces. Sometimes the concentrations of individual chemicals may exceed the maximal permitted concentrations even in factories. In such cases, the link between symptoms and cause can be relatively easy to prove.
More often there are low concentrations of many compounds, whose relative importance in evoking symptoms, malaise, or even just the feeling of bad indoor air is not known. Since moisture in the building may cause both chemical and microbiological adverse effects, these two types can exert mutual effects. For example, moisture may release ammonia from the filling beneath the carpeting. The importance of synergistic effects of chemicals and microbes in causing irritation symptoms is not well known. The symptoms associated with indoor air may be also related to insufficient ventilation or unpleasant temperature in addition to contaminants. In a large intervention study conducted in Helsinki, the only logical explanatory factor for many symptoms proved to be too high temperature (in excess of 23°C). In many cases no explanation at all can be found for the complaints attributed to poor indoor air quality.
In a large German study concerning so called multiple-chemical sensitivity, psychological factors and other stressors of life unrelated to the actual indoor air quality were found to be very important. Therefore also these factors have to be remembered when trying to resolve the indoor problems.
Whenever air quality is felt to be poor, working capacity tends to decrease and the amount of sick leaves tend to increase. Moreover one is dealing here with a life quality factor that may be very important with many indirect consequences. Often large and expensive repairs are conducted, but the present state of knowledge is often not good enough to ensure that even a major renovation will achieve a satisfactory solution.
Buildings associated with exceptional symptomatology are quite frequently causing concern, and many cases remain unresolved because of our deficient knowledge of the phenomenon.
Notes and references
- Synergistic effects are combination effects of two different causative agents; sometimes the effects are greater than the sum effect expected on the basis of the concentrations of both agents.
One level up: The air that we breathe
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