I say BS to this, it's the ambient light from cities........
The most vivid night time skies I had ever witnessed in my life was when on my regular pheasant hunting trips to N.W. Kansas and we stayed in the landowner's farmhouse out in the middle of nowhere.
Being an early riser, I'd get up at about 4:30 a.m., make coffee and go sit out in the yard smoking cigarettes and staring at the night sky..........
The owls and the distant coyotes just added to the experience........
Shame on me, I thought light pollution was exactly that, light atmospheric stuff such as smoke and smog.......Duh!