To be clear, "small quantities" are in units of parts per million. 5ppm (0.0005%) and the room smells of ammonia, 25ppm means you should be wearing a respirator, 500 ppm (0.05%) can be lethal.

Warning that 15% air-ammonia mixtures can burn is like warning that 100 kg of TNT could give you a concussion if it fell on your head. It's just not the concern at all.