Recently, heavy fog or foggy weather has occurred from time to time in Guangdong, which has caused serious traffic accidents on some expressways and caused casualties.
Fog is a common phenomenon of atmospheric condensation, especially in autumn and winter. When fog occurs, a large number of tiny water droplets or ice crystals are suspended in the air near the ground, which makes the air turbid and reduces visibility. People can only see people or things nearby. Generally, when the horizontal visibility of air is less than 1000m, it is called fog, while the visibility of fog that has caused major traffic accidents in recent times is less than1000 m.
There are two basic conditions for the formation of fog: first, there is enough water vapor in the air near the ground, which can reach saturation when it is cold; Second, the wind is very small at night, the atmospheric structure is relatively stable, and there are enough condensation nuclei-suspended matter. When fog forms, it is often accompanied by the corresponding inversion layer, that is to say, the closer to the ground, the lower the temperature and the higher the temperature. This is just the opposite of normal weather. Fog gradually forms at night and reaches its highest concentration in the morning. After the sun comes out, the ground temperature will rise, and the dense fog will gradually become thinner until it dissipates. Therefore, there is a saying that "ten fogs and nine sunny days". If it doesn't dissipate for a long time, it will rain, which is mostly related to the transit of autumn and winter fronts.
Fog does not fall from the sky, it and clouds are caused by the drop of temperature and the condensation of water vapor in the atmosphere. Fog can actually be said to be clouds near the ground. The so-called "walking under clouds and fog" means that clouds and fog are similar things, but in different spaces.
Fog is a kind of disastrous weather and is listed as one of the top ten disastrous weather in the world. Its direct harm is due to low visibility, which threatens the traffic safety of land, sea and air, and such accidents are numerous. It will also cause changes in insulators of transmission lines and open-air electrical equipment, and even lead to accidents.
Now scientists believe that fog is caused by the existence of "inversion layer", the atmosphere is very stable, convection is weakened, and pollutants such as water vapor and dust in the air are not easy to spread to the sky and can only stay near the ground. When the fog drops dissipate, all pollutants will enter the air, causing serious pollution and directly endangering human health. According to scientists' determination, the proportion of various harmful substances such as acid, alkali, salt, amine, phenol, dust and pathogenic microorganisms in fog drops is several times higher than that in ordinary atmospheric water drops. The harm of this pollutant to human body is most obvious in the respiratory tract. Therefore, people should not walk in the fog, let alone exercise in it.
If you run away,
1. Choose a good air environment. Avoid running in places with air pollution, because bad air will make people inhale a lot of harmful gases and hinder their health; It is best to choose a place with fresh air and beautiful environment. Running in places with many trees is not easy to precocious, especially in foggy days.
On foggy mornings, many people like to run long distances or do other sports on foggy roads, mistakenly thinking that the air in foggy places is fresh. Actually, this view is unscientific.
Fog is tiny water droplets floating at low altitude. The waste gas accumulated at low altitude in foggy days is not easy to dissipate, but more and more, and the harmful substances contained in fog are also increasing. Pathogenic microorganisms such as dust and smoke. Therefore, foggy sports will increase the inhalation of harmful substances, which will lead to bronchitis, pharyngitis, conjunctivitis and allergic diseases. In addition, inhaling too much dense fog air with high humidity will affect alveolar gas exchange.
2. Be timely and appropriate. Avoid running for too long and exercising too much, because morning running is on an empty stomach. If the running time is too long, the running speed is too fast, and the human body consumes too much, it may be harmful to health or have an accident.
3. Gradually relax after running. Avoid taking a cold bath immediately after running, because after running, the capillaries on the surface of human skin dilate and the pores of sweat glands open. If you take a cold bath immediately, your skin will suddenly be stimulated by cold, and the residual heat in your body will not be distributed, so it is easy to catch a cold.