Causes of haze weather

As a natural phenomenon, haze is caused by three factors. One is the increase in horizontal static wind phenomena. With the rapid development of urban construction, buildings are being built higher and higher, which increases the ground friction coefficient and significantly weakens the wind flow through the urban area. The increase in quiet wind phenomena is not conducive to the expansion and dilution of air pollutants to the periphery of urban areas, and it is easy to accumulate high-concentration pollution in urban areas. The second is the temperature inversion phenomenon in the vertical direction. The temperature inversion layer is like a pot lid covering the sky above the city, causing a temperature inversion phenomenon in which the upper air temperature is higher than the lower air temperature. Under normal climate conditions, pollutants diffuse from low altitudes with high temperatures to high altitudes with low temperatures, and are gradually discharged into the atmosphere in cycles. However, under the phenomenon of temperature inversion, the temperature at low altitude is actually lower, causing pollutants to stay and cannot be discharged in time. The third is the increase in suspended particulate matter. In recent years, with the development of industry, the number of motor vehicles has increased sharply, pollutant emissions and urban suspended particulate matter have increased significantly, which has directly led to reduced visibility, making the entire city look gray.

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