Why is there fog in the sky, why is it foggy, and how does it disappear?

When the air close to the ground cools to a certain level, the water vapor in the air will condense into fine water droplets and float in the air, reducing the visibility at ground level, a weather phenomenon called fog.

Saturation is reached when the water vapor contained by the air reaches its maximum capacity. And the higher the temperature of the air, the more moisture can be contained in the air. 1 cubic meter of air, when the air temperature is 4, the maximum amount of water vapor that can be contained is grams; When the air temperature is 20, 1 cubic meter of air can contain a maximum of grams.

If the air contains more water vapor than the amount of saturated water vapor at a certain temperature, the excess water vapor will condense and when enough water molecules combine with the tiny dust particles in the air, and the water molecules themselves will bond to each other, becoming small water droplets or ice crystals. The amount of water vapor in the air exceeds the saturation amount and condenses into water droplets, which is mainly caused by the drop in air temperature. This is also the reason why autumn and winter mornings are foggy.

It is formed after the vapor of water evaporates when it is cold, and generally there is no harm to people.

The other kind of fog looks like a hazy fog, and it is called haze, which is harmful to the human body. When encountering weather with a lot of haze, it is best not to exercise so as not to inhale too much of the harmful substances in the haze.

The water vapor in the air liquefies into small droplets when cold.

Fog is the liquid parameter of water vapor in the air that meets a low temperature at an interface such as glass, re-condensing the city. To disappear is to evaporate again into a gaseous state.

Depending on the type of fog, the causes of its formation are also significantly different. For example, radiation fog is mostly formed in rainy and cloudy nights, and the main cause is that the humidity of the lower layer increases and reaches saturation due to radiative cooling.

Advection radiation fog is mostly formed on the eve of sunny to cloudy weather, and the main causes are radiative cooling and advection humidification. Advection fog is formed in the rainy weather with high temperature and high humidity or in the early stage of rainy weather, and the main cause is that the humidity of the advection is very high.

Yes. In the past, everyone thought that fog was caused by water vapor, but it may not matter, but in fact, there are particles in fog water, so fog means that there must be pollutants in it. In fact, even in cities where there is no pollution, foggy days are not a good activity day because of the large amount of particulate matter.

If combined with the current increase in air pollution, the pollution content in the fog increases, so it is necessary to minimize going out on foggy days and shorten the time spent outdoors.

The water vapor cools rapidly and turns into small water droplets (water mist), and when the temperature stabilizes, the water droplets evaporate back into gas.

Water vapor rises on the ground, and when cold air descends, the two meet, and the combined dust particles in the air condense into fog.

If the ground heat is lost, the temperature drops, and the air is quite humid, then when it cools to a certain extent, a part of the water vapor in the air will condense and become many small water droplets, suspended in the air layer near the ground, which is fog.

This has to talk about the formation conditions of the fog: first, the cold and hot air under the ground is repentant, the second is humidification, and the third is the condensation nucleus (dust particles). Generally, when fog is formed, the air near the ground is colder and the upper part is hotter, and the air is not easy to convective movement, which is not conducive to the diffusion of air, and often forms a relatively stable temperature inversion.

When strong cold air arrives, the stable inversion layer is washed away, and the water vapor will condense into more water droplets, sometimes raining, and at the same time, it will also carry away dust particles, causing the conditions for fog formation to disintegrate. At this time, with the forward invasion of strong cold air, the foggy air moves upward along the front of the cold front, forming a convective movement of the air, which intensifies the spread of the buried fog, and the fog will dissipate soon after.

This explanation can be understood!

The commonly known particulate matter is expressed as PM10 and refers to airborne particulate matter with a diameter of 10 microns or less and a diameter of 10 microns or less, respectively. In a windless environment, particulate matter can be stably suspended for several weeks.

This fine particulate matter, itself is also an air pollutant, they are suspended in the air, in addition to blocking the line of sight and reducing visibility, but also play a role in adsorbing other pollutants in the air, such as aerosols with water mist, combined organic pollutants such as industrial emission compounds, soot and automobile exhaust, under the irradiation of sunlight to further chemical reactions, forming a carrier of more harmful pollution mixtures.

It is generally believed that smog is industrial emission pollution, urban construction and decoration, road dust, domestic heating smoke exhaust and automobile exhaust. Smog contains fine dust, volatile acid mist such as nitric acid sulfuric acid mist, organic hydrocarbons, heavy metals, etc., which happen to be the main components of heavy industrial air pollutants, dust, and automobile exhaust. In particular, coal-fired thermal power generation, metallurgy, chemical industry and dust-concentrated wood processing and building materials industry are one of the main enterprises of airborne microparticles and sulfides.

Most of the automobile exhaust is nitrogen oxides and carbon oxides, especially the emission of diesel vehicles has a greater content of particulate particles.

Industrial emissions and vehicle exhaust fumes constitute the most important hazards in smog pollution. With the saturation of the industrialization development of the major developed industrialized countries, the gradual withdrawal of polluting industries from the local area and the enhancement of environmental awareness, the process of atmospheric environment treatment has accelerated, and such serious pollution incidents have gradually decreased and disappeared. China is currently in a critical period of industrialization process, the development of basic industry and processing industry, fine industry are prosperous simultaneously, especially since the reform and opening up for more than 30 years, the urbanization process has accelerated, the popularization of automobiles, China has entered the ranks of quasi-developed countries, and the people's demand for industrial products and services, energy consumption has been increasing.

The coexistence and development of a large number of needed basic industries and untreated small factories and backward overcapacity have put tremendous pressure on the atmospheric environment. Due to the late start of China's industrialization process in the world's major industrial countries, but the speed of development is fast, so in just a few years, China's industrial production capacity has increased several times, and the accompanying industrial pollution and the rapid popularization of automobiles caused by the exhaust gas treatment problems are also more rapid than the problems experienced by the industrialized countries, and the degree is more than that.