Sick Building Syndrome
The presence of microorganisms in indoor environments may cause infective and/or allergic building-related illnesses. Some microorganisms under certain conditions may produce volatile chemicals that are smelly or irritating, thus contributing to the development of what is called sick building syndrome. Other factors relating to this subject are discussed in the segments on Indoor Air Quality and Ventilation.
Exposure to airborne fungal spores or other microorganisms can cause a variety of respiratory diseases. These range from allergic diseases, including asthma, to infectious diseases. In addition, acute toxic reactions and cancer have been ascribed to respiratory exposure to toxins. A large body of literature supports an association between moisture indicators in a building and symptoms of coughing and wheezing.
Microorganisms may cause building-related illness in indoor environments by affecting the immune system. Thus, allergic respiratory illness may develop due to inhalation of particulates containing microorganisms or their components, such as spores, enzymes, and cell wall fragments. Numerous cases of allergic respiratory illness reportedly affected people who manifested acute symptoms such as malaise, fever, chills, shortness of breath, and coughing. In buildings, these illnesses may occur as a response to microbiological contaminants originating from HVAC system components such as humidifiers and water spray systems, or other mechanical components that have been damaged by chronic water exposure. Affected individuals usually experience relief only after having left the building for an extended period in contrast to occupants with sick building syndrome, where relief is relatively rapid.
Sometimes indoor air quality scientists cannot successfully resolve complaints about the air in offices, schools, and other nonindustrial environments. Customarily, complaints are attributed to elevated pollutant concentrations; frequently, however, such high concentrations are not found indoors, yet complaints persist. The inability to determine cause and effect relationships between complaints and indoor pollutant concentrations has led investigators to define the cause of these complaints as sick building syndrome.
Exposure Standards and Criteria - The Occupational Safety and Health Administration (OSHA) has established Permissible Exposure Limits (PELs), which are published in the Code of Federal Regulations (CFR 1989a,b) under the authority of the Department of Labor. The ASHRAE Fundamentals Handbook Chapter on Indoor Environmental Health lists PELs for several particulates commonly encountered in the workplace.
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