So there I was this afternoon, sitting in my car waiting on my wife's flight to get in to Dulles Airport (IAD), in the cell phone parking lot. I was listening to some music on the radio when the rescue vehicle (ambulance) got a call to go somewhere. I know this, because it absolutely deafened me. Turns out (one of) the firehouse is right next to the lot. I've been in front of firehouses before when trucks have gotten calls and they weren't THAT loud.
This started me wondering if airport emergency vehicles have extra-loud sirens, due to the greater than normal ambient noise on an airport?