Fog is caused by water droplets in the air. But, Smog - Smog is Smoke + Fog.

It is a sign of severe air pollution.

Look at the image below of a city in China, notice the effect of smog in the atmosphere.

Effect of Smog.png

 

Let's discuss the differences between Fog and Smog

Fog Smog
Fog is caused by water droplets in the air Smog is made up of Smoke and Fog
It reduces visibility, but breathing in fog causes no harm.  Breathing in Smog can cause Eye Irritation, Asthma and decreases Lung's Breathing Capacity
Color of fog is white Color of Smog is usually blackish, but may change depending on other pollutants in the atmosphere 

fog-vs-smog---teachoo.jpg

  1. Class 8
  2. Chapter 18 Class 8 - Pollution of Air and Water

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo