I leafed through that page, and it still seems like the answer is: "To make sure the pollutants are dispersed and/or carried away enough to reduce exposure of people around the base."
Strangely, your comment shows up in light grey, indicating that you’ve been downvoted – for asking a genuine question! Upvoting your question (and its answers) to mitigate that.
Comments
I leafed through that page, and it still seems like the answer is: "To make sure the pollutants are dispersed and/or carried away enough to reduce exposure of people around the base."
Am I wrong?
You're right, but the less intuitive part is that the stack makes the air rise much more quickly; the exit velocity is higher the taller the stack.
That’s secondary. Smoke stacks were tall long before people cared about pollution (1800s).
Strangely, your comment shows up in light grey, indicating that you’ve been downvoted – for asking a genuine question! Upvoting your question (and its answers) to mitigate that.