What is the reason for the weather like this in Wuhan today?

As a natural phenomenon, smog has three factors. First, the phenomenon of static wind in the horizontal direction has increased. In recent years, with the rapid development of urban construction, buildings are built higher and higher, which increases the friction coefficient of the ground and weakens the airflow when passing through the urban area. The increase of static wind phenomenon is not conducive to the diffusion and dilution of atmospheric pollutants to the periphery of urban areas, and it is easy to accumulate high-concentration pollution in urban areas. The second is the phenomenon of vertical inversion. The inversion layer is like a pot cover over a city, which causes the inversion phenomenon that the temperature at high altitude is higher than that at low altitude. Under normal climatic conditions, pollutants diffuse from low altitude with high temperature to high altitude with low temperature and are gradually discharged into the atmosphere. Under the inversion phenomenon, the low-altitude temperature is lower, which leads to the retention of pollutants and cannot be discharged in time. The third is the increase of suspended particulate matter. In recent years, with the development of industry, the increase of motor vehicles, the discharge of pollutants and the increase of suspended solids in the city have directly led to the decrease of visibility and made the whole city look gray.

One of the hazards is affecting health. The composition of smog is very complex, including hundreds of atmospheric particles. Among them, aerosol particles with a diameter less than 10 micron are harmful to human health, such as mineral particles, sea salt, sulfate, nitrate and organic aerosol particles. Can directly enter and adhere to the upper and lower respiratory tract and lung lobe of human body. Because most atmospheric aerosols in smog can be inhaled by human respiratory tract, especially submicron particles will be deposited in upper respiratory tract, lower respiratory tract and alveoli respectively, causing diseases such as rhinitis and bronchitis, and long-term exposure to this environment will also induce lung cancer. In addition, because ultraviolet rays in sunlight are the only way for human body to synthesize vitamin D, the weakening of ultraviolet radiation directly leads to the high incidence of rickets in children. In addition, ultraviolet light is the main weapon to kill atmospheric microorganisms such as bacteria and viruses in nature. Hazy weather leads to the weakening of ultraviolet rays in the surface layer, which is easy to enhance the activity of infectious bacteria in the air and increase infectious diseases.

Second, it affects mental health. Whether the gray weather is easy to make people feel pessimistic, if it is not adjusted in time, it will easily get out of control.

The third is to affect traffic safety. When there is haze weather, outdoor visibility is low, pollution continues, traffic jams and accidents occur frequently.

The fourth is to affect the regional climate. Regional extreme weather events occur frequently and meteorological disasters occur one after another. What is even more worrying is that smog has also accelerated the early arrival of photochemical smog pollution in cities. Photochemical smog is a kind of light blue smog. Automobile exhaust and factory exhaust contain a lot of nitrogen oxides and hydrocarbons. These gases will undergo photochemical reactions under the action of sunlight and ultraviolet rays, resulting in photochemical smog. Its main components are a series of oxidants, such as ozone, aldehydes and ketones. It is very toxic and has a strong stimulating effect on the human body. In severe cases, people will have difficulty breathing, decreased vision, hand and foot convulsions and other phenomena.