Use mild solutions. You can also leave a pail of weak acid in the room for an extended time to clear the ammonia, which outgasses. There are also NH3 electrodes for pH meters, but they are costly and complex to use. It can also be removed with acid cleaners. Or protein scum, which again is susceptible to acid cleaners.
Ammonium salts are safe.
Except for undesirable odor or corrosive vapors and high pH when present in great excess, ammonia is not a hazard. The issue is more one of offensive odor or color, or presence of vapors to irritate worker's lungs. Robert A. LaBudde, PhD, PAS, Dpl.