I'm not sure about Cleveland specifically. But a similar industrial city, Pittsburgh, had a huge air pollution problem up thru the 1970s. See: http://www.the

I'm not sure about Cleveland specifically. But a similar industrial city, Pittsburgh, had a huge air pollution problem up thru the 1970s. See: http://www.theatlanticcities.com/arts-and-lifestyle/2012/06/what-pittsburgh-looked-when-it-decided-it-had-pollution-problem/2185/ http://www.theatlanticcities.com/arts-and-lifestyle/2012/06/... (The Atlantic again!) This qualifies as "the real thing". It's well-known local lore that local stonework was turned black by the soot. ("Black" is not an exaggeration.)