Is for example, the atmosphere seeming different a real physical phenomenon that could be detected by ML?
Everything that can be measured can be used as an input for ML algorithms. The things that "feel" different are the result of the "post-processing" your brain applies to the inputs it receives (olfactory, temperature, light intensity and -spectral composition, etc.).
The sensation is based on physical phenomena, though it might be interesting how much of it remains if we were to take the knowledge about the change of location away, e.g. would you feel the same way if you didn't know you were 3000 miles away? In other words, does knowing about the change in location sharpen your senses such that you subconsciously look for changes in the environment?