The report gives results of an extension of work done in Part 1 of the study, reported in September 1974. Of the five major sources of sulfur oxide emissions studied in Part 1, new or enlarged data bases are presented for three: utility plants, industrial boilers, and sulfuric acid plants. Cost models developed for the wet limestone process and the Wellman/Allied process are applied to these source groups, and the results summarized. Application of the Wellman/Allied system to Claus plants is also discussed. Economics are shown for a 'packaged' limestone scrubbing system for small industrial boilers. Cost models, derived from the model for substitute natural gas plants developed in Part 1, are included for low-Btu and intermediate-Btu gas plants. Production costs of substitute natural gas, low-Btu gas, and solvent refined coal are presented, based on actual coal prices in the U.S.