I like the red scene, because that palette seems more natural. If it's dark out and there's a giant ominous looming smoke-billowing factory as the center piece of whatever you're getting yourself into, I'd expect the air around it to be reddish from a combination of the smog and the amber-colored lights that are usually placed on and around factory exteriors.
(Tangentally related, I actually encountered something similar to this when I made a wrong turn in Pennsylvania and wound up in an old looking town that had a huge smoky factory looming in the back. It was a winter night and snowing at the time too, so it was a lot more white colored, plus I think the lights on the building were white. With the navigational error aside, it was a pretty badass scene to look at. After a bunch of research based on the silly road names we passed (Dumb Hundred Rd, Dick Schoolhouse Rd (pitch black and lead straight into the woods, noooope), Purdy Rd), it turns out that the town was Roaring Spring PA, and the factory is the paper mill that's there.
The green doesn't seem like a bad idea either, and the first thing it reminds me of is the Oddworld series with its hyper-industrialized settings, usually with a green haze as the backdrop (Contrast with the more natural environments you encounter later, where the green tones are plant life rather than the strange toxic neon green in the factories).
I'm torn too, but your idea of the palette changing from red to green seems really cool, like if the gate slowly opened and the haze faded from red to green as it happened, you could even throw in a music sting for the transition.