The main reason for the formation of haze

Many people have found that every winter, the amount of haze in the air becomes higher and higher. Especially in the northern region, due to the dry climate and strong winds and sand, haze weather has become a problem that troubles many people's daily lives. When there is smog, the air quality is low, which can easily cause respiratory infections among people. The visibility is also very low, affecting our daily activities. So what is the main cause of smog?

Do you know what causes smog?

1. Suspended particles

Suspended particulate matter is the main cause of haze formation. According to the different sources of suspended particulate matter, it can be divided into motor vehicle exhaust, industrial production waste gas, road traffic and construction site dust, heating waste gas and others. The content of nitrogen oxides in motor vehicle exhaust accounts for about 50% of the total suspended particulate matter and is the main source of particulate matter. The emission height of motor vehicle exhaust is just within the breathing range of the human body, about 0.3 meters to 2 meters, which poses a certain threat to the respiratory health and physical health of the human body. Oil quality and car ownership are important factors that directly affect motor vehicle exhaust.

2. Inversion occurs in the vertical direction of the atmosphere

The temperature inversion phenomenon refers to the situation where the temperature of the upper air in the urban atmosphere is higher than that of the lower air. When inversion occurs vertically in the urban atmosphere, an inversion layer will be formed and cover the city. Inversion will greatly limit the vertical air movement in the low altitude atmosphere, reducing the capacity of pollutants in the atmosphere. Pollutants will find it difficult to drift to high altitudes and will be blocked near the ground and in the low altitude, causing pollutants to accumulate and form haze.

3. Calm winds are generated in the horizontal direction of the atmosphere

The radial degree of circulation in my country's mid-latitude regions is relatively small. In northern regions such as Henan, North China and Shandong, the intensity of cold air has significantly weakened, the relative humidity of the atmosphere is too high, and the atmosphere is in a stable state. Under the influence of the uniform pressure field and low pressure load, the regional wind speed is too small, causing serious obstruction to the horizontal air circulation. There are many buildings in the city, and the wind flow is gradually weakened due to friction and obstruction, which increases a large number of calm wind phenomena. The dilution and diffusion of suspended particulate matter are affected, and they will accumulate in the suburbs, suburbs, suburbs and urban areas to form haze.