Multiple Exposure Holography of Moving Fibrous Particulate Matter in the Respiratory Range

The application of Fraunhofer (far- field) holography to the study of particulates in environmental situations is described. The use of the technique is illustrated with single and multiple exposure holograms of particles of ground talc containing both tremolite and asbestos. Size, velocity and behavior of the particles as they fall through air is obtained. Future uses of this technology are outlined.