Stack effect? I'm not totally sure about this...
Explanation:
Large amount of tiny particles of water droplets, dust and smoke are present on a misty day. These tiny particles in the air scatter blue colour of white light passing through it. When this scattered light reaches our eyes, the smoke appears blue.
155,500
I did this to the best of my ability. I have a hard time comprehending things sometimes so I’m so so so sorry if it’s wrong