A papermill in New Hampshire; doesn't smell like wood like you think it might, really strange smell, almost like a dead animal of some kind. ugh.
Pittsburg, TX. That's where the Pilgrim Pride chicken factory is.
Pig farm and an outhouse. I also agree with the papermill.
My ex-brother-in-law's family egg farm in upstate New York.
My grade school was located near the American Cyanamid plant. On damp days you could smell the chemicals.
Papermills and coke plants (converting coal to coke for steel mills)
I live 35 miles from the paper mill in Ashdown, Arkansas and when the wind comes from the east, you can smell it. They shut the mill down a few months ago.
I visited my cousin's turkey farm but don't remember if I'd classify it as the worst smell. I do remember going to a brewery that would definitely make the list.
When my daughter was small, we had to abort a tour of an Anheuser Busch brewery because she got sick from the smell. She remained very sensitive to that smell for a long time. We know because I was often guilty of making it at home. My wife still just barely tolerates it.