I used to live next to Martin State Airport in MD, just across the water, in the neighborhood where the stealth fighter crashed in 1997. The National Guard uses this airport, so A-10s and C-130s are constantly flying in and out of the airport. Depending on the winds, they would often fly directly over where we lived.
Air shows back then would last the entire weekend, so 2 days.
Loud and disturbing:
No louder than normal operations at the airport. A-10s and C-130s aren’t quiet. You don’t realize how large and loud an A-10 is until you see a tiny little Cessna take off on the same runway a couple of minutes later. There were two airshow events that I do remember being much louder than normal.
A pair of F-15s flew over the runway, pointed their noses up, and hit the afterburners. They went up so quickly that they ended up in commercial airspace and got in big trouble for it.
The aforementioned stealth fighter crash. That was loud. Took out an entire house, literally nothing left. Surprisingly, not much louder than the F-15s hitting their afterburners.
So, overall, not loud or disturbing. Although it is very weird to see a Soviet Mig flying over your neighborhood.
No more than normal operations on the airport. Looking on Google Maps, it looks like I lived about 3,000 feet from the end of the runway. I don’t remember any haze in the air or a smell of jet fuel or anything like that. There was probably more pollution on Eastern Avenue from all of the cars than there was pollution from the airport.
I personally don’t think there is much truth to the claims.
There is one thing that isn’t mentioned in the OP, and that is crowds and traffic. Driving anywhere near the airport while there’s a show becomes a bit of a pain in the backside.
People do that anyway. Any time there was an airshow, you’d have a crowd of boats in the waterways all around the airport (Middle River and all of the little creeks and inlets that feed into it). When the stealth fighter crashed, the pilot said that after the wing came off he tried to aim for the shore, so that he wouldn’t hit the neighborhood and wouldn’t come down on all of the boats. The plane didn’t handle very well with one wing, so he missed the shore and hit a house that was right on the shore.
There aren’t any decent fields near the airport, and the shoreline is mostly privately owned, so your best bet to view the airshows was to go out on the water.