trying not to be a smart@$$... but did you turn it on like the inspector did? or did you close the window that was inbreathing?

Seriously though, if the fan is making a lot of noise, then it may be trying to pull more air through it than it can lift from the rest of the house, in effect, cavitating the fan blades. Another issue would be the motor or fan belt (these are typically belt driven with the motor mounted to the side rather than connected directly to the fan blade) may need aligned or replaced. Also, fan belts tend to stretch and wear over time, similar to the serpentine belt in the cars today.