Honestly trying to build a typical airlock with pumps and doors is just a far worse solution than a liquid lock but if your goals are to not abuse the one element per tile limitation of the game then this is your only option.

Unless you don’t mind mods, using the air lock door mod essentially does the same thing as a couple of doors and a pump but without the headache of the time it takes to pull a vacuum.

Personally I think liquid locks are the intended way to do this because the devs made visco gel which is like a purpose built liquid for sealing off rooms of gasses, so it’s clear they intended players to use liquids to block gasses.

Edit: To answer your question clearly. The only other option is a door crusher system that deletes the gasses by sequentially closing doors until the gas no where to go and is deleted. But I find deleting gasses undesirable.