9.39 Design Case Study. A process engineer proposes a new solvent that will reduce the quan- tities required by the process and significantly reduce the quantities of solvent vapors released into the air inside the plant. The new solvent is perchloroethylene, and it is expected to reduce the solvent vapors absorbed into the plant air by 20% by volume as TABLE 9.3 Exposure Levels Morning exposures Afternoon exposures (4 hour) (4 hour) Acetic anhydride Sodium hydroxide 0.5 ppm 0.2 mg/m³ 1 ppm 0.3 mg/m³ Ammonium sulfide 3 ppm 4 ppm Calcium bisulfide 5 ppm 8 ppm Carbon disulfide 4 ppm 6 ppm Sodium sulfide 0.7 mg/m³ 0.8 mg/m³ Sodium sulfite 0.5 mg/m³ 0.5 mg/m³ compared to the old solvent (Stoddard solvent). You are called in as a Certified Safety Professional to evaluate the proposed change to the process. Do you support the proposed process change? Explain your position.