There are chimneys, like the one at our local nuclear power plant. They are big and when you fly over in a plane you still see the smoke piercing though the clouds. Smoke? No of course not just harmless water vapour of course. Just leave the Geiger counter at home, it might begin to tick. That is a professional chimney.
And then there are the medium sized chimneys, the ones that smoke all day and all night as well as all year: the permanent chimneys. Apparently also harmless, just burning the waste at the garbage plant.
And there are the local chimneys. Nothing so bad, just smoking away if someone lights a fire.
And there are even people that tend to turn into a human chimney now and again.