During this workshop the participants discussed several topics related to aerosol measurement. A partial listing of some aerosol particle parameters which might be useful for specific measurement applications, such as health effect determinations was developed and included the following: number, surface and mass concentration; aerodynamic diameter; shape including length, width, diameter, and fractal dimension; chemistry; refractive index; vapor pressure; charge; solubility; and density. The complex nature of aerosols prevents many potential users from making optimum use of available instrumentation. Several recommendations were developed to assist in the establishment of standards for aerosol instrument performance. It was recommended that the appropriate committees of various organizations consider developing voluntary consensus standards for two types of instruments; aerosol mass measuring instruments and optical particle counters. Government organizations should pool their resources to develop an accurate direct reading portable aerosol mass monitor. The workshop participants recommended that committees consider developing promotional, educational, and guidance materials for use of direct reading instrumentation. A standardized approach should be developed to present specifications of instrument capabilities. And lastly, the committee urged that manufacturers of direct reading aerosol instruments consider conforming to the international guidelines on quality assurance.