It doesnt make that much sense on how air pollution affects all machines though.
It should affect only things that burn (reduces air oxygen quality), like boilers.
Rain would corrode blocks away if the pollution is too high (slowly, all the way down to bedrock) , requiring a special acid-proof block to protect yourself.
Ah yes, good old realism.
This is an area where balance takes precedence. The point here isn't to model a fun and interesting pollution simulation. Its to make higher tier machinery less useless, period. I employ a bit of handwavium and say "all machines are subject to particulate matter in the air. So smog can clog anything with moving parts, which is everything."
I might pick a very few machines and render them completely immune, but it really breaks the target objective. And it would require updating every wiki entry to indicate whether a machine is immune or subject to pollution. Its easier to just say "pollution screws with your machines."