In some cases, the pollutant available in the inventory is not the same as the pollutant for which speciation profiles have been developed. At this time, the only known case of this situation is when the inventory is collected for VOC (or for reactive organic gases [ROG]) but the speciation profiles are available for TOG. For this situation, VOC-to-TOG factors have been developed that Spcmat assigns to the inventory sources based on the sources’ SCCs. The factors are input using the GSCNV file, which can support multiple pollutant-to-pollutant conversions in the same file.