Ugh! You're impenetrable. Why am I even trying?
Smoke of all kinds is bad. Got it? No one goes around burning coal at a park. In your ideal world, people would go around smoking weed at parks. People at the park would get extra smoke in their air. In my ideal world, people would smoke weed and cigarettes at home, and the park goers would only get a tiny bit of the smoke, instead of a relatively large amount. You seem to think that if something is bad, we should make it worse. That makes no sense.
This has nothing to do with coal. I'm not saying my idea is any better for the environment, because, no one is going to smoke enough to affect the environment. They can affect people within 25 feet of them, though.