Sick Building Syndrome
SICK BUILDING SYNDROME
The term "sick building syndrome" (SBS) more specifically termed "nonspecific building-related illness," describes a set of common and nonspecific symptoms that are experienced by individuals in office and other nonindustrial workplace settings but remit when the individuals are away from that environment. Symptoms typically include fatigue; cognitive complaints; headache; shortness of breath; irritation of the nose, oropharynx, and eyes; rashes; and complaints of unpleasant odor in the workplace. It is critical to distinguish SBS from building-related illness, which refers to conditions more readily diagnosable by practitioners and characterized by abnormal signs. These include carbon monoxide poisoning, asthma, hypersensitivity pneumonitis, and upper respiratory infections. The symptoms and paucity of signs that characterize SBS overlap substantially with the symptoms of various other medically unexplained syndromes such as chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivities, and even psychiatric conditions characterized by somatic symptoms. The key is that with SBS the symptoms wax and wane with exposure to a particular building environment. Sorting out their diverse causal influences is the key to prevention, and involves integration across many fields.
A number of factors have been identified in experimental and field studies which contribute to SBS, although there remains much uncertainty about specifics of exposure, dose, susceptibility, and in particular the development of chronic symptoms once an afflicted individual is removed from a building exposure. Strong observational epidemiologic data has shown relatively high rates of symptoms in office workers in a variety of countries and climates. At least 20 to 35 percent of workers report such symptoms, even in nonproblem buildings. One important clue to SBS is that rates of symptoms are strongly correlated with mechanical ventilation systems as opposed to natural ventilation. Elevated carbon dioxide levels are a marker for inadequate ventilation, but are not toxic, per se. Relative humidity below 20 percent and above 60 percent are correlated with mucous membrane discomfort or general symptoms.
It is clear from controlled exposure studies, as well as observational studies, that even relatively low levels of volatile organic compounds (VOCs) can acutely produce many of the symptoms of SBS, and that these symptoms remit once exposure is terminated. Attempts to document objective correlates of these symptoms with neuropsychological or respiratory tests have not been very successful. VOCs are emitted from many construction materials as well as office products, and while most noticeable with new buildings, many emission sources are chronic. VOCs can also be reintroduced during building maintenance and renovation, as well as normal business activities.
A number of studies document an increased rate of symptoms, independent of allergy, in buildings with moisture problems and/or documented
Workplace stress can contribute to symptoms, according to numerous studies. The mechanism and degree of interaction of SBS with physical factors needs further study. Individual psychological characteristics can certainly influence who reports symptoms and the degree of distress associated with a given level of symptoms. Nevertheless, the strong ability of environmental factors to trigger symptoms means that preventive or ameliorative strategies aimed solely at workplace stress or personal characteristics will not be satisfactory over the long run.
HOWARD M. KIPEN
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