The question you then have to ask yourself is this: Would a pro smog advocacy group emerge to keep it going? Unlikely you say?
Think about it. Cold practicality and profits could come together to work a partnership of pushing face masks, eye protectors, and the undeniable fact that a higher death rate might be more cost effective than getting off coal any time soon. Especially when one considers that the old would be the most vulnerable to lung related diseases. You couple that with a treatment policy of just giving them, say, morphine to keep them comfortable, as well as quiet, and you could have a real consensus builder among the elites; who of course could live elsewhere.
And lest you start getting too smug about something like this not happening hear just remember: the money being spent to keep coal, and fracking, and barely safe operations in a wide range of industries where poison can happen either directly, or indirectly, because of cutting corners.