Double counting to the Nth power. We've been burdened down with single harm pollutants, eking out benefits one hypothetical harm at a time. Everything causes everything. I'm afraid to ask for an example. We're show casing NOx as the all purpose pollutant.
All combustion produces NOx, because air is basically nothing but nitrogen and oxygen.
So kill NOx and you've killed combustion, the Great Gore's greatest goal. We let one of our chief air Heads, Doug Grano, do a test launch at a recent coal-burner NOx control festival. They were too stunned to mutter. It was beautiful. And don't you see, every other pollutant causes a similar, if not identical, set of harms.