"Dec 1989." "EPA/600-S9-89-047." Caption title. At head of title: Project Summary.

The Flexible Regional Emissions Data System (FREDS) is a modular software system that takes the NAPAP annual point and area source emissions inventories and derives a resolved emissions data base suitable for input to atmospheric pollution simulation models, such as the Regional Acid Deposition Model (RADM). The primary functions of FREDS are to resolve annual emissions to hourly values, to apportion county-level area source emissions to grid cells, and to perform speciation of selected pollutants into user-defined species classes. FREDS consists of seven primary modules written in SAS and Fortran which perform the tasks of extraction of desired data from the annual inventories, temporal and spatial allocation, speciation, conversion to modeling format and quality control of the flow of data through the system. The order in which the allocation and speciation modules are to be executed is flexible, and not all of these modules must be executed, allowing for different applications and desired formats. The user can specify the parameters of execution and define the allocation and speciation both geographically and by source type by means of control options files and allocation factor files. FREDS was first designed and used to process the 1980 NAPAP emissions inventories, and has been significantly enhanced for processing the 1985 NAPAP emissions inventories. The flexible design of FREDS ensures that it will be a useful system for processing other emissions inventories for modeling applications.