What is fog, haze and haze?

In daily life, people usually use words such as fog, haze and haze to describe the weather conditions with high air humidity and low station temperature. However, fog, haze and haze have different meanings.

The fog and sea fog formed by the great change of airflow is formed by the condensation of water vapor in the air close to the ground when the temperature is lower than the dew point. If the fog rises off the ground, it becomes a cloud. It is a milky white suspension system composed of a large number of water droplets or ice crystal particles, and the relative humidity of the air is close to 100%. When the concentration of suspended particles is high near factories and other places, it will appear yellow-gray Fog will reduce the horizontal visibility of the air, which can be divided into light fog, fog, fog and dense fog. Light fog usually appears in the morning and evening, and the horizontal visibility is1km ~10 km; Fog visibility is 0.5 km ~1km; The visibility of fog is100 ~ 500m; Visibility in dense fog is less than 100 meter.

In Chinese dictionaries, haze is interpreted as cloud gas and light fog, while in meteorology, it refers to the phenomenon that tiny water droplets are suspended in gas. The horizontal visibility is generally higher when haze appears than when fog appears, which is generally above 10 km. At present, there are many suspended particles in urban air, which provide a large number of condensation nuclei of water vapor, so there are more smog. It is reported that Shenzhen has 100 days a year. But haze is not a strict concept, so it is rarely used in meteorology.

In history books, the word "haze" indicates the weather with sandstorm, and there is a saying that "wind and rain are haze". Haze is a weather phenomenon in meteorology, which refers to the phenomenon that a large number of extremely fine dry dust particles float evenly in the air, making the air with horizontal visibility less than 10 km generally turbid. Haze will make bright objects slightly yellow and red in the distance, and dark objects slightly blue. When water vapor condensation intensifies and air humidity increases, haze will turn into fog. The formation of smog is closely related to the discharge of pollutants. In cities, motor vehicle exhaust and other smoke and dust emission sources emit micron-sized particles, which stay in the atmosphere. When adverse weather such as inversion and still wind appears, smog is formed.

Generally speaking, when the above three weather phenomena occur, the air is turbid, the particulate matter pollution is serious, and the narrow air quality is poor, especially in haze and dense fog. So try to avoid outdoor activities during this time.