In autumn and winter, it is the peak period of haze weather. How does haze weather occur?
I think everyone should be very familiar with haze weather this time, especially in winter, which is the peak period of haze weather. The environmental pollution caused by haze weather is very serious, especially in the big cities in the north. Then I will give you an analysis of the current haze weather.
How smog occurs
The causes of smog are various, such as tail gas emissions, industrial production emissions, waste incineration for power generation, dust from construction sites, volcanic eruptions, etc. , Smog pollution is generally caused by the mixing of various pollutants. Smog pollution has existed since ancient times. Human activities or natural activities such as slash-and-burn farming and volcanic eruptions are likely to cause smog pollution. Especially after we enter the modern era, the rapid consumption of electricity, high population concentration, and destruction of ecological environment have all created suspense for the occurrence of haze pollution.
There are three factors that cause haze weather: First, the physical source of granular construction site dust. Among them, the soil type in the Loess Plateau area of my country is most likely to generate granular construction site dust particles. Second, poor exercise causes dust on the construction site. For example, when the mortar in the road dries up and is turned around by the wheels of a vehicle, it will cause dust in many construction sites. Third, the dust sources and movement differences at the construction site accumulate within a certain spatial range, and the particles eventually aggregate with water to form haze.
Why there is no haze weather in summer
Summer air currents (temperate cyclones & tropical cyclones) are frequently active and water vapor is transported well, which is conducive to causing rainfall, more frequent rainfall and high wind temperatures. , which is beneficial to the diffusion and elimination of PM2.5, so the PM2.5 concentration value is the lowest in summer of the year. The temperature is high in summer and water evaporates quickly, which is not conducive to solidification. Therefore, there is basically no haze weather in summer.
Large-scale haze weather mainly occurs under large-scale atmospheric circulation conditions with weak cold air and good water vapor conditions, with calm or light winds at low altitudes near the ground. Due to the high humidity and large water vapor in haze weather, fog droplets provide adsorption and reaction sites to accelerate the conversion of reactive gaseous pollutants into liquid particulate matter components. At the same time, particulate matter can also easily act as condensation nuclei to accelerate the generation of haze. The two interact with each other. function and quickly form pollution.