S2S-Tool: U.S. EPA's SPECIATE-to-SMOKE Tool generates GSPRO and GSCNV files that are used by SMOKE to generate gridded emissions for photochemical modeling. All profiles are in the U.S. EPA's SPECIATE database, and the type of GSPRO/GSCNV files generated by the S2S-Tool are dependent on the speciation methods employed for the desired modeling platform. SPECIATE is a database of organic gas, particle, and mercury speciation profiles. These profiles provide greater specificity than what is needed for a chemical mechanism within a photochemical model. The S2S-Tool bridges this gap and translates SPECIATE data into a format that is chemical mechanism specific.