4hw.org: have you done a good job of protection during the high incidence period of haze in winter? We usually put haze together, because they do mix together, but fog and haze are really different concepts. Do you know the difference between fog and haze? Let's look at it together!
What's the difference between fog and haze?
With the deterioration of air quality, haze weather phenomenon appears more and more serious. In many areas of China, haze weather phenomenon is combined with fog as a disaster weather early warning forecast. Collectively referred to as haze weather. In fact, fog and haze are quite different from each other in some way.
Fog and haze are the same as visual obstacles. However, the causes and conditions of fog and haze are quite different. Fog is a large number of tiny water droplets or ice crystals floating in the air. The formation conditions should have higher water vapor saturation factors. When fog occurs, the air is humid, and the relative humidity of the air often reaches 100% or nearly 100%. In case of fog, the effective horizontal visibility is less than 1km. When the effective horizontal visibility is 1-10km, it is called light fog. With the daily change of air humidity, fog is more common or more concentrated in the morning and evening, and relatively lightens or even disappears in the daytime. When there is haze, the air is relatively dry, and the relative humidity of the air is usually below 80%. The reason is that a large number of extremely fine dust particles, smoke particles and salt particles float in the air evenly, which makes the effective horizontal visibility less than 10km. The daily variation of haze is not obvious. When there is no big change in the air mass and the air mass is relatively stable, it lasts for a long time, sometimes for more than 10 days.
The difference between haze and fog
Different forms
Haze: haze is a small solid particle suspended in the air, including dust, sulfuric acid, nitric acid and other compounds.
Fog: fog is a small particle of water suspended in the air.
Different colors
Haze: haze is composed of various compounds. Due to its physical characteristics, there are more light with longer scattering wavelength, yellow and orange gray.
Fog: the fog is composed of small water droplets. Due to its physical characteristics, the scattered light has little relationship with the wavelength, so the fog is milky white and cyan white.
Different moisture content
Haze: haze is the air suspension with relative humidity (moisture content) less than 80%.
Fog: fog refers to the air suspension with relative humidity (moisture content) greater than 90%.
Different distribution uniformity
Haze: the haze particles contained in the haze are small and light, which are generally evenly distributed in the air.
Fog: fog is an aerosol system composed of a large number of tiny water droplets or ice crystals suspended in the air near the ground. It is the product of condensation of water vapor in the air near the ground. The distribution of fog in the air is uneven, and the closer it is to the ground, the greater the density.
Visibility is different
Haze: the haze is evenly distributed in the air, with small particles and low density, which has a certain impact on the light, but the impact is not as big as the fog, with low visibility, generally within 10 kilometers.
Fog: as the fog is closer to the ground, the greater the density, the greater the impact on the light, and the visibility is very low, generally within 1 km.
Boundary clarity is different
Haze: the haze has a wide range, small density and small particles. It has a certain transition effect with the clear sky area, and the boundary is not obvious.
Fog: the fog has a small range, high density and great influence on light, so the fog boundary is obvious.
Different vertical thickness
Haze: the particles in the haze are light in weight, evenly distributed, and generally 1-3km thick.
Fog: small droplets of fog have a large mass. Under the action of gravity, the cloud will be close to the ground, and the thickness is generally tens to 200 meters.
Different durations
Haze: haze is a small solid particle, not easy to settle, slow digestion speed and long duration.
Fog: the fog lasts for a short time. Generally, small water droplets sink to the ground under the action of gravity, and the increase of atmospheric temperature will also make the water droplets evaporate.
Social impact is different
Haze: haze is a small particle of various compounds, harmful to human health and plants.
Fog: fog is a tiny water drop suspended in the air, which will fall to the ground in a period of time, with little impact on people's life and health.
Different treatment methods
Haze: the most fundamental way to deal with haze is to reduce the emission of pollutants. In order to reduce the harm to the body, you can wear a haze mask to go out.
Fog: the fog does not need special treatment. Generally, the fog is easy to appear in the morning and disappear after the sun comes out.