What is the difference between fog and haze?

Every time you wake up early and see the gray outside, do you have a feeling that you can’t tell whether it is fog or haze? I believe many people are stupid and can’t tell the difference, although the two are visually Look, they are very similar, but the impact of the two on the body is very different. If you encounter haze weather, it is better to reduce outdoor exercise as much as possible, which is more beneficial to health. So how to distinguish the two?

Fog and haze weather

1. Distinguish between fog and haze

1. Fog is a natural phenomenon, which is a large number of fine particles suspended in the atmosphere close to the ground. A visible collection of water droplets (or ice crystals). Fog mostly appears in autumn and winter and is the product of water vapor condensation (or sublimation) in the air near the ground. The presence of fog will reduce air transparency and reduce visibility.

2. Haze, also known as haze, is mainly caused by human factors. It is caused by dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles in the air that make the atmosphere turbid, blur the vision and cause Visibility deteriorates. If the horizontal visibility is less than 10,000 meters, the visual range obstruction caused by this non-aqueous aerosol system is called haze or haze.

Fog and haze weather

2. What is the difference between fog and haze?

1. The components are different. Fog is composed of water droplets; haze is composed of dust particles, smoke particles or salt particles.

2. The relative humidity is different. Fog is a phenomenon of water vapor condensation, which requires a high relative humidity, generally above 90%. Haze is a collection of dust particles, smoke particles or salt particles. When it forms, the relative humidity of the air is usually below 80%.

3. The maintenance time is different. Fog has the characteristics of locality and short time. When it forms, the concentration changes rapidly, and the visibility is not uniform in all directions. Fog mostly appears from night to the next morning, and usually weakens and dissipates after noon, with obvious formation and dissipation. Daily changes. Haze has a gradual formation process and can last for several days after formation. It has the characteristics of relatively uniform visibility in a wide range and in all directions.

Hazy weather

4. Different vertical heights. Fog appears near the ground, and its vertical thickness is only a few hundred meters, while the height of haze can reach a height of 1km or even 3km, and the height of the stretch is relatively high.

5. The health effects are different. Fog is tiny water droplets suspended in the air and has little impact on human health; however, most of the dust in the haze can be inhaled by the human respiratory tract, affecting health.

6. Particle sizes are different. The particle size of mist droplets is 100-102μm, which is visible to the naked eye. The particle size of haze is 10-3-10μm, which is invisible to the naked eye.

7. Different colors. Fog is mostly milky white, while haze usually looks yellow or gray because it scatters more visible light with longer wavelengths.