This report is a summary of the results of Tasks 3 and 4 which conclude the Phase 1 portion of this program. Tasks 1 and 2 were summarized in AiResearch Report 78-15161. Task 3, entitled Materials Evaluation, is a laboratory evaluation of candidate materials and coatings exposed to various H/sub 2/SO/sub 4/ environments; the evaluation includes the determination of a corrosion rate from the field test modules. Task 4, entitled Fouling Evaluation, is an evaluation of the fouling rates of different heat exchanger surface configurations exposed to different diesel exhaust conditions.