If the morons would just reduce the red tape to build new more efficent, cleaner burning plants the old plants would get shut down due to attrition. Can't do that, none of the lawyers in government would get rich that way.
The dirty little secret of enviro regs is the best available current technology ploy. We could do better than now, if the regs didn't push you to the edge of the technology. Parts per thousand is cheaper than parts per million which is cheaper than part per billion. Require new plants to improve things, not to set the state of the art. Then conditions will improve. You wouldn't learn to run marathons by starting at 26 miles. You work your way up to it.