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The Clean Air Act, passed in the mid-1960s, focused national attention on cleaning up outdoor air but directed little interest toward improving the quality of indoor air—even though people spend only 10–20% of their time outdoors and the rest of their time indoors at home or at work. Studies conducted during the past three decades confirm that indoor air quality (IAQ) problems can cause or contribute to a variety of symptoms and sometimes illnesses in building occupants, as well as reductions in productivity. Concentrations of some pollutants inside buildings may exceed standards established for outdoor concentrations.

The term building-associated illness is reserved for health problems that develop in nonindustrial settings customarily considered nonhazardous, such as homes, schools, and offices. Indoor air contamination is linked to a wide variety of building materials and consumer products.


It is possible to divide building-associated illnesses into two categories: (1) acute short-latency illnesses and (2) potentially chronic long-latency illnesses. The nature of the exposures that may give rise to each type differs substantially. Table 47–1 presents a classification scheme for building-associated illness. The principal focus of this chapter is on the acute short-latency illnesses.

Table 47–1.Types of building-associated illness.

The short-latency illnesses include sick-building syndrome, mass psychogenic illness, specific illnesses resulting from identifiable sources of noxious materials, certain infectious diseases, building-associated hypersensitivity pneumonitis, and dampness-associated asthma exacerbations. These conditions are characterized by a relatively acute onset, closely related in time to the individual's presence within the building and often relieved by removal from further exposure. Some of the building-related illnesses do not resolve promptly on leaving the building. In 1987, a committee on indoor air quality for the National Research Council defined building-related illness as those specific clinical syndromes resulting from exposure to indoor air contaminants, for example, hypersensitivity pneumonitis or Legionnaires disease. In contrast, sick-building syndrome refers to the occurrence, in more than 20% of the work population, of a variety of nonspecific symptoms and minimal or no objective findings, wherein it is not possible to make a specific diagnosis.

In contrast, the long-latency illnesses include cancer and chronic pulmonary diseases perhaps resulting from long-term low-level exposure to contaminants in indoor air. Because of the long induction-latency periods for these conditions and their multifactorial origin, it is much more difficult to establish a causal link to the building exposure. Agents in indoor air that may be responsible for such illnesses include cigarette smoke, asbestos, radon gas, oxides of nitrogen, polycyclic aromatic hydrocarbons, ...

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