unfortunately i'm not terribly happy with how this mod works because even making the pollution absorption values insanely high (like 1.0x10^8 per minute) the current chunk will only ever have so much in it and the machine is mostly inactive. placing them right adjacent to furnaces will help prevent runaway pollution, but I have started working with pollution cleaning modules for furnaces instead - the base game has them included as a ModuleType, but hardly anyone makes use of it.