My twenty year old house has cheapo ceiling exhaust fans that clang and make all sorts of weird noises but they still work! If I were an Engineer calculating the fastest way to exhaust "foul smelling bathroom gases"...what kind of exhaust fan would I buy?
I would think running the fan for thirty seconds after the occurance of foul smelling gases should be quite a sufficient amount of time for a well planned exhaust fan to rid the bathroom of noxious odors!
Bill