A fossil-fuel steam power plant operates at about 50% of Carnot thermal efficiency. It has been suggested that the air pollution from a plant that operates at 1000 F would contribute 1/2 the pollution (per ton of coal burned) that the present system that operates at about 1500 F. The heat rejection temperature is 70 F. For the same electrical output what is the percent difference in the pollution resulting from the combustion? Then, Calculate the optimum heater pressures.