Passion

Now you're thinking with portals. Not sure how air pressure would work if it was looped back onto itself, though - it'd probably have some sort of wind-tunnel effect as the air constantly fell through the loop under its own weight. What's the terminal velocity of air? 

Hang on, Mobius loop would not have a defined center of gravity, would it? How do you even determine which direction should air "fall"? What force would be there to apply pressure?

Would the particles simply be in chaotic disarray, colliding against each other? But it indicates that, after particles were placed in loop, something set them in motion.

Also, now that I think of it, wouldn't perceived temperature while falling be extremely low? You'd probably freeze to death rather than starve first.

If you're somehow falling down a bottomless/looped hole the air also has to be falling down the hole by the same gravitational token. Without the air to slow you down you could achieve speeds only limited by how much the friction of the walls of the hole slows the air flow near the edges radiating in towards the centre. If there's no friction at all you'd end up falling at a speed asymptotically approaching the speed of light.

There's a lot that depends on the properties of the hole walls too - the whole scenario could be a closed universe without any outside gravitational effect or heat diffusion through the exterior, in which case nothing would fall anywhere and the only energy in the hole would come from whatever event created it and the instantaneous influx of energy that took place in the moment you somehow fell into the thing (which could itself have caused the chaotic motion of formerly stationary particles). If the hole universe had enough energy invested in it when it formed it could be comfortably warm - energy can't be destroyed in a closed universe and heat is the lowest form of energy so it'd be in a stable thermodynamic equilibrium excepting your presence (although that would be remedied once you starved to death).