This single reel of magnetic tape contains 2 files relevant to VERSION 2 changes to the UNAMAP air quality models. The first file contains all of the source code affected by the VERSION 2 changes, in a partitioned or element-file format. Batch versions of all models were included and the HIWAY Model was entirely replaced. File 2 is sample test data for the batch versions. Manuals are available for APRAC and CDM. Accession Numbers for the publications are PB-213-091 and PB-227-346-AS, respectively. Manuals for HIWAY and the three point source models are available in draft form and should be published early 1975. The FORTRAN Source code is largely self-documenting and should be machine independent in most cases. Tape recording mode is 9-track, 800 frames per inch. EBCDIC code, odd parity. Physical records each contain 10 logical records (i.e., 10-card images per block). Tape can be copied to 7-track without loss of data.