Percent Efficiency = [1 + (a - b)/(c - d)] * 100
where:
a = concentration obtained in step (8).
b = concentration obtained in step (9).
c = concentration obtained in step (6).
d = concentration obtained in step (7).
If converter efficiency is not greater than 90 percent corrective action will be required.
40 C.F.R. §86.523-78