What is the fog like in Zhengzhou, Xuchang and Xinyang these days?

It's not fog, it's foggy. Haze refers to a large number of tiny dry dust particles uniformly suspended in the air, which makes the air with horizontal visibility less than 10 km generally turbid, making bright objects slightly yellow and red in the distance, and dark objects slightly blue. According to the visibility, smog can be divided into mild, mild, moderate and severe.

The smog warning signal is divided into yellow and orange levels. Haze with visibility less than 3000m may appear within 6 hours, or haze with visibility less than 3000m may be yellow warning, haze with visibility less than 2000m may appear within 6 hours, or haze with visibility less than 2000m may be orange warning.

Fog is an aerosol system, which consists of a large number of tiny water droplets or ice crystals suspended in the air near the ground, and the visibility is reduced to below 1000 meters. Smog is also called atmospheric brown cloud. There are four areas with serious smog in China: Huanghuaihai area, Yangtze River basin, Sichuan basin and Pearl River Delta.

The difference between fog and haze lies in the water content: when the water content reaches 90%, it is called fog, and when the water content is lower than 80%, it is called haze. Between 80% and 90%, it is a mixture of fog and haze, and the main component is haze.

Zhengzhou, Xuchang and Xinyang are all smog orange warnings these days.

As a natural phenomenon, smog has three main factors.

First, the phenomenon of static wind in the horizontal direction has increased. In recent years, with the rapid development of the city, buildings are built higher and higher, and the obstruction and friction make the airflow weaken obviously when passing through the urban area. The phenomenon of still wind is increasing, which is not conducive to the diffusion and dilution of atmospheric pollutants.

Second, the vertical direction is reversed. This inversion phenomenon that the air temperature at high altitude is higher than that at low altitude limits the vertical movement of air at low altitude in the atmosphere, making it difficult for pollutants to drift to high altitude and be blocked at low altitude and near the ground.

The third is the increase of suspended particulate matter in the air. In recent years, with the rapid increase of urban motor vehicles, the emissions of urban pollutants and suspended solids have greatly increased. In the case of severe smog weather, try to take public transport and drive less private cars.

In moderate and severe haze weather, the elderly and children should pay attention to the accumulation of a large number of aerosol particles harmful to health in the air near the ground, which can directly enter and adhere to the upper and lower respiratory tract and lungs of the human body, causing diseases such as rhinitis and bronchitis, and can also induce lung cancer in this environment for a long time. Therefore, elderly children with weak resistance and people susceptible to respiratory diseases should go out as little as possible, or reduce outdoor activities and wear masks when going out.