... they are something else. I have factory (city blocks) and on each side, in between the tracks, I have a pair of air filters in each chunk[1]. They hold the pollution in the city block, nothing escapes. Pollution? What is that?? Biters are just out there minding their own business.

Now, I do crank through the plastic making the filters (up above 5K and still climbing and using near 100/min) and recycling the air filters uses part of my polluted water city block and burns through charcoal, but the byproducts of that is well worth it, too.

[1] My city blocks are chunk-aligned at 5x5 chunks, which makes for 10 air filtration units per side, shared between the adjacent block.