How is the fog formed?

1. How did the fog form? Fog and cloud are water vapor condensate composed of small water droplets or ice crystals floating in the air, but fog is generated in the near layer of the atmosphere, while cloud is generated in the upper layer of the atmosphere. Since fog is water vapor condensation, we should look for its reason from the conditions that cause water vapor condensation. There are only two reasons why the water vapor in the atmosphere is saturated: first, evaporation increases the water vapor in the atmosphere; On the other hand, the air itself will get cold. Cooling is more important for fog. When there are condensation nuclei in the air, condensation will occur if the water vapor in saturated air continues to increase or melt away. If the condensed water drops reduce the horizontal visibility below 1 km, fog will form.

2. The influence of fog travel on health:

In foggy days, the combination of pollutants and water vapor in the air will make it difficult for pollutants to spread and settle, which makes most pollutants gather at the height where people often move. Moreover, some harmful substances will become more toxic when combined with water vapor, such as sulfur dioxide becoming sulfuric acid or sulfite, chlorine hydrolyzing into hydrogen chloride or hypochlorous acid, and fluoride hydrolyzing into hydrogen fluoride.

So the air pollution in foggy days is much more serious than usual. Another reason that needs to be emphasized is that the particles that make up the fog core are easy to be inhaled and stay in the human body, while the amount of air inhaled during exercise is much more than usual, and there will be a lot of particles inhaled during exercise in foggy days, further aggravating the harm of harmful substances to the human body.