The last task for the chemical speciation processing is creating the speciation intermediate files. The Spcmat program creates a mole-based speciation matrix (ASMAT_L, MSMAT_L, or PSMAT_L) and a mass-based speciation matrix (ASMAT_S, MSMAT_S, or PSMAT_S), as previously mentioned. These matrices can have any number of pollutant-to-species conversions; the Spcmat program will open multiple speciation matrix output files if the number of pollutant-to-species conversions is greater than 120 (the limit for the number of variables in an I/O API file). Spcmat opens and writes as many files with 120 variables (using the FileSetAPI wrapper) as are needed to store the data. In addition, the Spcmat program writes a supplementary speciation file (ASSUP, MSSUP, or PSSUP) that contains the speciation profile assignments for each source. The structures of the SMOKE intermediate files output by Spcmat are provided in Section 7.14, “Spcmat”.