There was a heavy fog in Jinan yesterday, and the air was filled with pungent smell. Many citizens can't stand it They travel with their noses covered. What happened?

1. The atmospheric pressure is low and the air does not flow, which makes the tiny particles in the air gather and float in the air. These particles may include ground dust, automobile exhaust and secondary pollutants emitted by factories.

2. The ground is dusty and the air humidity is low, which makes people and traffic on the ground stir up the dust and further aggravate the air pollution.

3. Automobile exhaust is one of the main pollutants. With the increase of the number of cars in cities, automobile exhaust emissions also increase accordingly, which may be a factor of smog.

4. Secondary pollution produced by factories, such as industrial residual tail gas from chemical plants, may also have an impact on smog.

5. Pollutants such as CO2 emitted by heating in winter may also have an impact on smog.

This pungent smell may be produced by mixing these pollutants. Citizens cover their noses out of the instinct to protect their health when they travel, because this air quality may cause harm to the human body. It is recommended to go out as little as possible in this weather. If you have to go out, you must wear a qualified mask to protect your health.