Megan tells Don, "The radio said there's a smog emergency. The air's toxic. I don't want that in here." In the world Matthew Weiner's created, this is less about the historical reference point and much more about symbolism, however, the smog did cause real problems for real New Yorkers of the time.The smoggiest day the city experienced that year was on November 24th (in Mad Men it's mentioned as Megan is preparing Thanksgiving dinner), and there are varying reports that the smog killed anywhere from 169 to 400 people in the city that year.