The fog is so heavy at this time! Ten or twenty meters away, you can't see people clearly. The smoke in the air makes me breathless, cough and have a sore throat. How is this smog formed?

The formation of smog generally has the following reasons:

First, the dust on the construction site.

Second, automobile exhaust emissions.

Third, heating in winter and emissions from coal-fired power plants.

Fourth, the humidity near the ground is relatively high, and the particles in the air gather and condense.

Fifth, industrial spraying emissions.

Sixth, the emissions in the production process of some factories. It is best to wear a mask when going out in foggy weather, and try not to go outdoors.