Why is Linyi always foggy?

When the water vapor contained in the air reaches the maximum, it reaches saturation. The higher the temperature, the more water vapor is contained in the air. 1 m3 air, the maximum water vapor capacity is 6.36g at 4℃; When the temperature is 20℃, the maximum water vapor content in 1 m3 air is17.30g. If the air contains more water vapor than saturated water vapor at a certain temperature, the excess water vapor will condense out. When enough water molecules combine with tiny dust particles in the air, the water molecules themselves will combine with each other and become small water droplets or ice crystals. The water vapor in the air exceeds saturation and condenses into water droplets, which is mainly caused by the temperature drop. This is why it is foggy in autumn and winter morning.

If the ground heat is lost, the temperature drops and the air is quite humid, then when it is cooled to a certain extent, some water vapor in the air will condense out and become many small water droplets suspended in the air layer near the ground to form fog. Both it and clouds are caused by temperature drop, and fog can actually be said to be a cloud near the ground.