"Encyclopedia Knowledge" What is the color of smog?

Haze is usually yellow or orange-gray, and fog is usually milky white or bluish white.

Haze (wù‘mái) is a combination of fog and haze.

Due to the deterioration of air quality, haze weather phenomena have increased and the harm has worsened. Many areas in China incorporate the haze weather phenomenon into fog as a disastrous weather warning and forecast. Collectively referred to as "haze weather". In case of haze weather, try to take anti-virus measures. So how is smog formed? What color is smog?

How is smog formed?

The same thing between fog and haze is that they are visual range obstacles. However, the causes and conditions for the formation of fog and haze are very different. Fog is a large number of tiny water droplets or ice crystals floating in the air. The formation conditions require a high water vapor saturation factor. When fog occurs, the relative humidity of the air often reaches 100% or close to 100%. Fog may become more common or thicker in the morning and evening as the air humidity changes day by day, and become relatively lighter or even disappear during the day. When fog occurs, the effective horizontal visibility is less than 1KM. When the effective horizontal visibility is 1-10KM, it is called light fog. There is actually a difference between 'fog' and 'haze'. Sun Leng, a senior engineer at the Climate System Monitoring Office of the National Climate Center, pointed out that fog refers to the weather phenomenon when the visibility is lower than 1 km due to the condensation of suspended water vapor in the atmosphere; while the formation of haze is mainly caused by a large number of particles suspended in the air and meteorological conditions. ***The result of the same effect, there are three causes:

——The phenomenon of quiet wind in the horizontal direction increases. Buildings are getting taller and taller in cities, and the blocking and friction effects significantly weaken wind flow through urban areas. The increase in quiet wind phenomena is not conducive to the diffusion and dilution of suspended particles in the atmosphere, and is easy to accumulate around urban areas and suburban areas;

——Temperature inversion occurs in the vertical direction. The inversion layer is like a pot lid covering the city. This inversion phenomenon in which the temperature at high altitudes is higher than that at low altitudes restricts the vertical movement of air at low altitudes in the atmosphere. Suspended particles in the air are difficult to float to high altitudes and are blocked in the atmosphere. Low altitude and near the ground.

——An increase in suspended particulate matter in the air. With the growth of urban population, industrial development, and the surge of motor vehicles, pollutant emissions and suspended solids have increased significantly, directly leading to reduced visibility.

In fact, dust "haze" will also be produced during home decoration. The dust in the room is not only harmful to the health of workers and users, but also increases the burden of cleaning. When the dust is serious, it will also bring more trouble to the decoration project. Hidden danger!

The color of haze

Fog is a natural phenomenon composed of a large number of tiny water droplets or ice crystals suspended in the air near the ground, and the visibility is reduced to less than 1,000 meters. Haze refers to the phenomenon that dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles in the air make the atmosphere turbid. Its core substance is dust particles suspended in the air.

Look at the moisture content: anything above 90% is called fog, anything below 80% is called haze, and 80% to 90% is a mixture of fog and haze.

Second, look at the visibility: when the horizontal visibility of the target object is reduced to 1,000 meters, it is fog, and when the horizontal visibility is less than 10,000 meters and it is caused by dust particles, it is haze.

Third, look at the thickness and color: the thickness of fog is only a few dozen meters to 200 meters, while the thickness of haze is 1,000 meters to 3,000 meters; the color of fog is milky white, bluish white, and haze is yellow or orange-gray; fog is The boundary is very clear. After passing the "fog area", the sky may be clear, but the boundary between haze and the surrounding environment is not obvious.