The periodical is published to inform air pollution personnel of the Environmental Protection Agency (EPA), and others, of technical literature recently accessioned by the Air Pollution Technical Information Center (APTIC). For each accession, its abstract number, APTIC accession number, bibliographic citation, and abstract are given. Translations are cited with their sources whenever possible. The subject fields are as follow: Emission sources; control methods; measurement methods; air quality measurements; atmospheric interactions; basic science technology; effects-human health; effects-plants and livestock; effects-materials; economic aspects; standards and criteria; legal and administrative; social aspects; and general and miscellaneous. All abstracts are listed under one of the above subject fields. This issue contains abstracts 20049-20974.