I Remember Skies of Blue..Do You?

I went out this morning early to try to get a better picture of my previously posted “Burble” find, with the hopes of getting a good sun-shot thru it, as this gives it an awesome glow. I clicked off half a dozen shots, disgruntled with all the outcomes, (and not missing the 35mm dinosaur days of puckers on the film reel in the darkroom), well, I was left staring at awe of the colors, and lack thereof, as the grey cover of particulates blew in the upper winds. These are non existent in any of my parents massive photo collection from the 70’s and 80’s. Just the occasional short jet exhaust trails like small darts in the sky occasionally. What have we let them do?