Air pollution technical information processing—the microthesaurus approach

The purpose of this report is to describe the microthesaurus approach to indexing technical literature, as used within the Air Pollution Technical Information Center (APTIC) of the National Center for Air Pollution Control (NSAPC). Using the Thesaurus of Air Pollution Terms as a base, a microthesaurus was constructed by dividing the field of air pollution and its effects into major categories such as Humans and Animals, Plants and Foods, Pollutants, Measurements, and others. These major categories were further divided to sub‐categories such as Respiratory Diseases, Suspended Particulates, and Materials Deterioration. Finally, the subcategories were reduced to very specific terms such as asthma, bronchitis, emphysema—all subordinate to Respiratory Diseases. Approximately 1,300 terms were arranged hierarchically on three display sheets with each term coded according to the number‐color scheme of a Jonkers Termatrex system. These sheets were subsequently used to deep‐index several thousand air pollution documents. It was concluded that the micro‐thesaurus approach provided the following: (1) consistency of indexing; (2) elimination of coding and spelling errors; (3) retrieval of both broad and highly specific information; and (4) adaptability to manual and mechanized systems.