or just don't keep the pollution data in the block data but in the chunk dataHow would you code the pollution spread?
You would need to force update of every air block every x seconds, and id imagine keeping track of whats "indoors" and "outdoors" becomes quite difficult in large halls in mountains or lengthy unclosed caves.
That said, love the idea. And on the point of humans influencing pollution, imagine boiling water on a coal-powered oven indoors without a way to letting the smoke out. The pollution gets real quite fast