The research literature provides strong evidence that characteristics of buildings and their indoor environments influence the prevalence of several adverse health effects. These include communicable respiratory disease (e.g., common colds and influenza), allergy and asthma symptoms, and acute sick building syndrome (SBS) symptoms such as headaches, and irritation of the eyes, nose, throat, and skin. For example, in six studies, the number of respiratory illnesses in building occupants varied by a factor of 1.2 to 2.0 as a function of building characteristics such as rate of ventilation with outside air, type of ventilation system, and occupant density (see table). Allergy and asthma symptoms are often a consequence of indoor exposure to allergens that may originate indoors or outdoors. Several methods can be employed to reduce allergen exposures. Changeable building factors such as ventilation rates, indoor pollutant concentrations, and quality of building cleaning can influence the frequency and severity of SBS symptoms. In addition to influencing health, research suggests that the indoor environment, especially temperature and lighting, can affect worker performance directly by a fraction of a percent to a few percent.

We estimated the costs of the building-influenced adverse health effects from statistical data and published papers. The annual (1993) health-care costs for acute respiratory infections are about $30 billion. These respiratory infections result in about $35 billion in annual sick leave plus restricted activity at work. The health-care costs and productivity decreases from allergies and asthma are about $13 billion per year. Productivity losses from SBS symptoms are quite uncertain but were estimated to be around 2 percent among office workers, costing an estimated $50 billion annually.

• IAQ: Health