exactly what do you mean??I am a bit confused here.are you mixing ammonia and bleach per chance??I cetainly hope not as this could be a very fatal and toxic occurance,really.how long it takes for anything including any sort of chemical to actually dissapate depends on alot of factors,whether it is in an enclosed space,like inside a room or if it is outside,wind,temp,you know.in what context are you asking this question?? FB