"Normalized stoichiometric ratio (NSR)" means the actual mole ratio of urea to NOx divided by the theoretical stoichiometric ratio, which is 0.5 for the reaction between urea and NOx.
N.H. Code Admin. R. Env-A 1302.35
(See Revision Note at chapter heading for Env-A 1300) #9803, eff 10-31-10