What is the cause of smog formation?

There are several reasons for the smog weather.

1.

The main factor when the atmospheric pressure is low and the air does not flow. Because the air does not flow, the tiny particles in the air gather together and float in the air.

2.

The ground is dusty and the air humidity is low. People and vehicles on the ground stir up dust.

3.

Automobile exhaust is the main pollutant emission. In recent years, there are more and more cars in cities, and automobile exhaust emissions are a factor of smog.

4.

Secondary pollution produced by factories.

5.

CO2 and other pollutants emitted by heating in winter.