Why does it suddenly fog at night sometimes?

The duration of fog at night is 8- 10 hour.

I. Formation

1, which is formed by radiation cooling, mostly appears at night and early morning when there is plenty of sunshine, breeze, rich and stable water vapor near the ground or inversion, and is called radiation fog in meteorology.

2. Warm and humid air moves horizontally. After passing through the cold ground or water surface, the water vapor in the air is gradually liquefied by cold, which is called advection fog in meteorology.

The smog in the city is caused by another reason, that is, human activities.

Second, dissipation.

1. As the underlying surface gets warmer, the fog drops evaporate.

2. With the increase of wind speed, the fog will dissipate or dissipate into clouds; Then turbulent mixing, water vapor upload, heat transfer, and evaporation of droplets near the ground.

Extended data:

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 the closure of expressway in many places and delays in airport flights.

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.