Okay, first, let’s think how many actual cities there are in Ohio. Columbus, Cincinnati, Cleveland, Dayton, Toledo, and then you can argue about Akron and Canton and Youngstown. Woo-frickin-hoo. Dayton is the fourth or fifth largest city in Ohio, depending how you count; so saying it’s the fourth smoggiest city isn’t saying much.
As for mid-sized cities in the US, I can’t tell you. But smog isn’t one of our problems. Ozone, sinus pressure, allergens, yes, thanks to the valleys and the weather patterns. Smog particulates, no.
Now, I remember back in the Seventies when we had multiple large smoke-emitting factories and all kinds of gas guzzler cars. Even then, even on the most foggy days, the air just wasn’t high in smog particles. I never really knew what smog was, until I visited LA in the Nineties. (And was instantly aware that the place really wasn’t fit to live in, as far as air is concerned. The burning of the eyes and nose….) The air is cleaner now than it was in the Seventies or the Nineties, by far.
The only exception to this is that, last year, there was a big junkyard fire for several days, where there was all this burning tire gunk in the air. This was an exceptional event, the kind that had people remembering the big barrel factory fire back in the Sixties. They really were warning people not to be spending a lot of time outside when the wind from that was blowing in their direction; but that’s not exactly counting as smog. Sheesh.
So either this environmental group is comparing incredibly minuscule amounts of smog, or they’re counting ozone days as smog days, even though they’re not necessarily the same. Either way, “total BS” is the obvious conclusion.