Why is there smog? Continuous pollution is the primary cause

Everyone is very afraid when talking about smog. Now the smog in society has become more and more serious, especially in winter. If we want to reduce the smog, we must know the reasons for its formation. In fact, the most important thing is that the environment we live in is constantly polluted.

1. Pollution is still the root cause

Sun Jun, chief forecaster of the Central Meteorological Observatory, believes that due to the low winds and humid air in most parts of the country recently, many places are shrouded in smog. From the beginning of the month to now, the conditions for "calm and stable weather" have been met in most parts of the east and south. The wind is relatively weak and the humidity near the ground is relatively high, which is not conducive to the horizontal and vertical diffusion of pollutants in the air. In addition, due to the high humidity near the ground, fog is more likely to form at night and in the morning. If there is no obvious cold air activity, it is easy to cause large-scale fog and haze weather.

However, some experts believe that weather factors are the direct factors that trigger and aggravate the impact of smog, but the fundamental factor is the continuous emission of pollutants. The total amount of major air pollution emissions far exceeds the environmental capacity. Experts analyzed that in addition to the calm weather and relatively saturated air humidity, strong atmospheric particulate pollution transmission in the high altitude and more secondary pollution anthropogenic emissions are also the "culprits" of the severe smog weather in the south.

2. Calm weather is a driving force

Meteorological experts said that calm and stable weather is the "culprit" causing this round of smog weather. As the recent cold air activity in my country has been significantly weaker, the wind speed is low and the atmosphere is relatively stable, the weather conditions are not only not conducive to the diffusion of pollutants, but also easily cause pollutants to accumulate near the ground, leading to frequent smog weather. In addition, due to various factors in autumn and winter, the concentration of aerosols (liquid or solid particles suspended in the air) increases, which can easily lead to haze.

Since the emission of aerosols (pollutants) over a large area will not change much over a period of time, the formation and changes of haze weather are controlled by meteorological conditions. In January this year, meteorological conditions favorable for the formation of haze appeared, which were rare in recent years. The biggest difference from the previous period was that the meridional direction of the circulation in the mid-latitudes was small, which made the intensity of the cold air in the north weaker during this period, and the warm and humid air flow in the south relatively strong, and the atmosphere was calm and the relative humidity was high.

3. The nature of smog in East China and Beijing-Tianjin-Hebei is different

Experts pointed out that compared with usual times, the severe haze in East China regions such as Jiangsu and Shanghai, with a large area, long duration and local PM2.5 concentration exceeding 300 micrograms per cubic meter, is indeed rare.

The smog in East China and the Yangtze River Delta this time is different from the smog in the Beijing-Tianjin-Hebei region. From the perspective of causes, the smog in Beijing-Tianjin-Hebei is closely related to the terrain, while the East China region is basically plains and is less affected by the terrain. The smog mainly occurs because the air pressure conditions have stabilized and a large amount of water vapor comes from the sea. From the perspective of the nature of the smog, the air humidity of the smog in East China this time is higher and the visibility is lower.