As soon as winter comes, haze will easily appear in the north. Do you know how haze is formed? How to distinguish fog and haze? Fog is water vapor, which is a natural phenomenon, while haze is a mixture of water vapor, dust and smoke, mainly caused by human factors.
Ten differences between fog and haze
1. Difference of existence form
Fog: fog is a small particle of water suspended in the air.
Haze: haze is a small solid particle suspended in the air, composed of dust, sulfuric acid, nitric acid and other compounds.
2. Color difference
Fog: the fog is composed of small water droplets. Due to its physical characteristics, the scattered light has little to do with the wavelength, so the fog is milky white, cyan white or pure white.
Haze: haze is composed of various compounds. Due to its physical properties, there are more light with longer scattering wavelength, so haze is yellow and orange gray.
3. Difference in thickness
Fog: the thickness is generally tens of meters to 200 meters. This is because the mass of small water droplets is large, and the cloud will be close to the ground due to the effect of gravity.
Haze: the thickness is generally 1km-3km. Because haze particles are light in weight and distributed evenly.
4. Difference of humidity
Fog: air suspension with relative humidity (moisture content) of more than 90%. When fog occurs, the air is moist.
Haze: when the relative humidity (moisture content) is lower than 80%, the air is relatively dry when haze occurs.
The mixture of haze and fog is 80% - 90% relative humidity, but the main component is haze.
5. Difference of distribution uniformity
Fog: the fog is not evenly distributed in the air, and the closer it is to the ground, the greater the density.
Haze: the particles of haze are small, light and evenly distributed in the air.
6. Differences in daily changes
Fog: fog is most likely to appear from midnight to early morning. It will dissipate in the morning.
Haze: the daily variation characteristics of haze are not obvious, which may appear at any time of the day and may not dissipate in one day.
7. Difference of boundary clarity
Fog: the boundary is very clear and obvious. After passing the 'fog area', it may be thousands of miles in the clear sky. Because of the small scope, high density and great influence on the light, the boundary is obvious.
Haze: the boundary between haze and surrounding environment is not obvious, because haze has a wide range, small density and small particles, which has a certain transition effect with the clear sky area, and there is no obvious boundary.
8. Difference of visibility range
Fog: the horizontal visibility of the fog is within 1km, because the closer the fog is to the ground, the higher the density and the greater the impact on the light, so the visibility is very low.
Haze: the horizontal visibility of haze is less than 10km, because 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 fog, with low visibility.
9. Difference in duration
Fog: short duration. Because the small water droplets in the fog will sink to the ground, and the rising temperature of the atmosphere will make the water droplets evaporate, the fog will be less and less.
Haze: long duration. Because the small solid particles in haze are difficult to decompose, do not settle, and the digestion speed is slow.
10. Difference of impact on human body
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.
Haze: haze is a small particle of dust particles, smoke particles, salt particles and other compounds suspended in the air, which is very harmful to human health. After long-term inhalation into the respiratory tract, the human body will cause respiratory system diseases and cardiovascular diseases.