A stationary source simulator facility has been developed and is in use by EPA personnel at the Environmental Science Research Laboratories, located in the Research Triangle Park, N. C. The facility, which is essentially a wind tunnel, is so designed as to allow the selection of a wide variety of stationary source emission characteristics. The tunnel is used in various research projects related to the development of measurement instrumentation for gases and particulate pollutants. The characteristics required for many research projects can be provided automatically with an accompanying computer.