[Bored chemist]

Remember that outdoor atmospheric gases are mixed by turbulence and convection

Indoor ones are too.
Which is why this is obviously wrong...

H2S being denser than air, it will vent though the lowest holes.

[alancalverd]

If only the manufacturers and users of industrial gases possessed your wisdom and insight. And politicians too! No need to worry about rogue states installing gas centrifuges - they don't work!

[Bored chemist]

No need to worry about rogue states installing gas centrifuges - they don't work!

In the real world, nobody actually said that, did they?

[Bored chemist]

If only the manufacturers and users of industrial gases possessed your wisdom and insight.

Most of them do.
That'/s why you don't see them trying to separate gases by leaving them to settle out.