Smog is a mix of natural fog – tiny droplets of water in the air and carbon dioxide smoke from pollution. IT forms a thick, dirty, smelly atmosphere.
When I put the lighted paper in the jar, I made some of the water moisture inside the jar evaporate into water vapor.
The ice made a small amount of water vapor condense. It turned into droplets of water in the jar. This appears as a mist in the jar.
Warm damp air meets cold air. The cold air makes the moisture in the warm air condense into tiny droplets that are held in the air. If there is no wind, fog forms.