It would be nice getting away from the smog and traffic for a while.
Smog was cited as a major factor that contributes to global warming.
He waved a hand at the smog and all that caused it.
The Atlanta night was muggy and dark; a thin layer of smog trapped the city's light and made the sky glow an eerie yellow-orange.
Noxious gases, as they're released into the air, cause chemical changes in the atmosphere which result in the formation of smog and acid rain.