Since the 1880s, there have been repeated reports worldwide of toxic effects to wildlife from air pollution. Incidents in North America were recorded as early as the 1920s and as recently as last year. The effects have ranged from death and injury to increased incidence of infectious diseases, and they are the result of exposure to both gaseous and particulate emissions. Compared with other threats to wildlife, for instance, pesticides, the toxicological relationship between air pollution and effects in wildlife is not well understood. Our limited understanding is based primarily on reports of symptoms observed in the field and on information extrapolated from studies in livestock and laboratory animals. Few controlled wildlife studies, such as those that have evaluated pesticide effects, have been conducted. Current air quality standards cannot be assumed to protect wildlife from the effects of air pollution. This article reviews the current state of knowledge of air pollution and wildlife toxicology and the continuing threat air pollution presents to wildlife. The available information on reported effects of gaseous and particulate pollutants (i.e., sulfur dioxide, hydrogen sulfide, oxidants, arsenic, cadmium, fluoride, lead and selenium) on terrestrial wildlife, along with similar toxicological data for domestic animals, is summarized. Information on the toxic effects, tolerance levels, pathways of contamination, and risks to wildlife from air pollution is given, and gaps in knowledge are pointed out. Areas where research is needed are identified. Copyright © 1988 SETAC