Are fog and haze two different concepts?

Fog and haze are two different weather phenomena with some differences.

Haze: it is mainly composed of a large number of tiny dust particles, smoke particles or salt particles suspended in the atmosphere and accumulated in the lower part of the lower atmospheric stability layer. If the weather is clear, the air is dry and stable, and the wind is weak, a large number of tiny dry dust particles invisible to the naked eye float evenly in the air, making the air turbid, and bright objects in the distance appear yellow or red, and black objects appear slightly blue. This is haze. At this time, the horizontal visibility in the air is usually below 10 km.

The weather condition of haze formation is to control the stability of local air mass, so haze may appear at any time of the day, and it is generally easier to appear in the morning and evening. The appearance of smog shows that the atmosphere has been polluted.

Fog: it is a weather phenomenon that a large number of small water droplets or ice crystals float in the air layer near the ground, which reduces visibility to a certain extent. The phenomenon that the horizontal visibility is less than 1 km in heavy fog; The horizontal visibility of light fog is 1~ 10 km, which is very similar to haze. Fog radiates fog, advection fog, steam fog and uphill fog. Advection fog is formed because when warm and humid air flows to the cold sea surface or land surface, the lower layer of the air contacts with the cold surface and cools, reaching saturation condensation. This kind of fog can appear at any time of the day and usually lasts for a long time.

Similarity between fog and haze: both of them are visual distance obstacles, that is, a weather phenomenon that affects visibility, but they are different in nature.