Progress made over the last few years in the area of aerosol sampling was reviewed with specific information given pertaining to direct reading aerosol instruments and their applications. The Respirable Dust Monitor was the first direct reading dust monitor to be developed by NIOSH. The largest single dust monitoring program was the coal mine dust monitoring program enforced by the Mine Safety and Health Administration. The Real Time Aerosol Monitor was designed later and has been used as supplemental equipment to respirable dust filter sampling. In 1980, NIOSH supported the development of a personal, end of shift readout monitor based on the Tapered Element Oscillating Microbalance. A portable x-ray fluorescence analyzer was developed to help resolve the problem of aerosol monitoring instruments which are not specific for the toxic component of an aerosol. The Fibrous Aerosol Monitor was developed for a specific contaminant, asbestos (1332214) fibers, in real time concentrations. The Aerodynamic Particle Sizer was developed to analyze direct aerodynamic sizing of aerosol particles in the respirable dust size range. A recent development was a miniaturized condensation nucleus counter, used as a field quantitative fit tester for respirators. Laboratory and field studies using some of these samplers were reviewed.