There is a difference between smog and fog, do you really know?

There are many chances of haze and fog appearing in the cold winter. They both look white, but in fact there are huge differences between the two, such as different shapes, colors, water contents, distribution uniformity, visibility, boundary clarity, vertical thickness, duration, etc.

1. Different shapes

Haze: Haze is small solid particles suspended in the air, including various compounds such as dust, sulfuric acid and nitric acid.

Fog: Fog is small particles of water droplets suspended in the air.

2. Different colors

Haze: Haze is composed of various compounds. Due to its physical properties, it scatters more light with longer wavelengths, and is yellow, orange and gray.

Fog: Fog is composed of small water droplets. Due to its physical properties, the scattered light has little to do with the wavelength, so the fog appears milky white or bluish white.

3. Different water content

Haze: Haze is air suspended matter with a relative humidity (water content) of less than 80%.

Fog: Fog refers to air suspended matter with a relative humidity (water content) greater than 90%.

4. Distribution uniformity is different

Haze: The haze particles contained in haze are small, light in mass and 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. Fog is unevenly distributed in the air, and the density increases as it gets closer to the ground.

5. Different visibility

Haze: Haze is evenly distributed in the air, with smaller particles and lower density. It has a certain impact on light, but the impact is not as great as fog. The visibility is low, generally within ten kilometers.

Fog: Since the density of the fog is greater the closer it is to the ground, the impact on light is also greater, and visibility is very low, generally within 1 km.

6. Different boundary clarity

Haze: Haze has a wide range, low density, and small particles. It has a certain transition effect with clear sky areas and the boundaries are not obvious.

Fog: The range of fog is small, the density is high, and the impact on light is great, so the boundary of fog is obvious.

7. Different vertical thickness

Haze: The particles in haze are light in mass, evenly distributed, and the thickness can generally reach 1-3 kilometers.

Fog: The small water droplets in fog are relatively large in mass. Under the influence of gravity, the clouds will be close to the ground, and the thickness is generally from tens to two hundred meters.

8. Duration is different

Haze: Haze is small solid particles that are not easy to settle, dissipate slowly and last for a long time.

Fog: Fog lasts for a short time. Generally, small water droplets sink to the ground under the action of gravity, and the increase in atmospheric temperature will also cause the water droplets to evaporate.

9. Different social impacts

Haze: Haze is small particles of various chemical compounds that are harmful to human health and plants.

Fog: Fog is tiny water droplets suspended in the air, which will fall to the ground after a period of time and have little impact on people's lives and health.

10. 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 when going out.

Fog: Fog does not require special treatment. Generally, fog tends to appear in the morning and disappears on its own after the sun comes out.