Causes of haze weather

As a natural phenomenon, smog has three factors. First, the phenomenon of static wind in the horizontal direction has increased. With the rapid development of urban construction, buildings are built higher and higher, which increases the friction coefficient of the ground and obviously 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 number of motor vehicles has soared, and the emissions of pollutants and suspended particles in cities have greatly increased, which directly leads to the decrease of visibility and makes the whole city look gray.

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