How is the smog formed?

Hazy weather is usually formed by the mixed action of many pollution sources. However, in the smog weather in different regions, the role of different pollution sources is different. Now let's look at the causes of smog formation.

1. Atmospheric pressure is low, and air stagnation is the main factor. 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 is a factor of smog.

4. Secondary pollution produced by factories.

5.？ CO2 and other pollutants emitted by heating in winter.