What symbol is used for "fog" in weather forecast?
When the water vapor contained in the air reaches the maximum, it reaches saturation. The higher the air temperature, the more water vapor it contains. 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.
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Effects of foggy days:
In the foggy days of urban agglomerations, the combination of pollutants and water vapor in the air will make it difficult to spread, which makes most pollutants gather at the height where people often move, causing certain damage to human health. Try not to engage in outdoor activities and open-air gatherings in foggy days; Try to wear a mask when you go out; Don't open the window when there is morning fog.
Fog will reduce visibility and have a great impact on roads, shipping and maritime traffic. Zero-degree weather often leads to highway closures and airport flight delays in many places.
Try not to drive out in foggy weather. Be sure to turn on the front and rear fog lights when driving, control the speed, and remove the fog on the windshield in time. When parking in foggy weather, be sure to turn on the fog lights and don't sit in the car.