The biggest reason for the serious haze is the air pollution! Winter is the season of frequent haze, many people are confused, why is the serious haze in winter? Today's editor will give you a detailed introduction of why the haze in winter is the most serious.
Why the haze is serious in winter
For haze weather, pollutant emission is the "culprit", and adverse weather diffusion conditions are the "accomplice". The fundamental way to solve air pollution is to reduce pollution emission and green environment. Therefore, the Municipal Office of pollution control and haze reduction also calls on citizens to drive less one day a week for green travel.
Why fog and haze occur frequently in autumn and winter
① The poor air mobility in the near surface layer is an important reason for the formation of fog and haze. In summer, strong convective activities and strong air mobility are not conducive to the formation of fog and haze. In autumn and winter, the air mobility is weak, which is conducive to the formation of fog and haze. On the one hand, gale weather is not conducive to the stability of air stratification near the ground, on the other hand, gale weather is conducive to dispelling fog and haze. Since 1961, the average wind speed in the Middle East of China has decreased significantly, especially in spring and winter, followed by autumn. This is an important background for the increase of fog and haze in autumn and winter in China in recent years.
② Autumn and winter are the seasons with frequent cold air activities, which are not conducive to the occurrence of fog and haze. In recent years, the decrease of cold air process in autumn and winter is also an important reason for the frequent occurrence of fog and haze in China. Since 1961, the cold air process has been decreasing in winter and autumn.
③ Rainfall and snowfall can clear and wash the fog and haze in the atmosphere. More precipitation in summer is not conducive to the occurrence of fog and haze, while less precipitation days in autumn and winter are conducive to the occurrence of fog and haze. Statistics show that the number of precipitation days in autumn and winter has decreased since 1961.
④ When haze occurs, the weather conditions are characterized by stable and dry air mass, and there are many days when such weather conditions are met in autumn and winter. It is found that the humidity in autumn and winter is small, and in the past 50 years, the autumn shows a significant downward trend, and the autumn and winter show more and more dry signs, which is conducive to the increase of haze days and the decrease of fog days.
Why is it easy to have haze in winter
1. Poor air mobility:
The reason why haze is easy to occur in winter is that the air mobility in the near ground layer is weak in autumn and winter, and pollutants are easy to accumulate, which is not conducive to diffusion. Generally speaking, there are four ways of pollutant diffusion: atmospheric turbulence (irregular movement of air micro cluster), convective diffusion, advection diffusion and strong weather activity (precipitation, gale, etc.). However, due to the fall and winter seasons, the above-mentioned four diffusion ways have been reduced. In addition, the inversion layer often occurs in autumn and winter seasons, which further makes the atmosphere in a static and stable state, so that pollutants cannot be diffused.
2. Frequent cold air activity:
Autumn and winter are the seasons with frequent cold air activities, which are not conducive to the occurrence of fog and haze. In recent years, the decrease of cold air process in autumn and winter is also an important reason for the frequent occurrence of fog and haze in China. Since 1961, the cold air process has been decreasing in winter and autumn.
3. Less precipitation:
Rainfall and snowfall can clear and wash the fog and haze in the atmosphere. More precipitation in summer is not conducive to the occurrence of fog and haze, while less precipitation days in autumn and winter are conducive to the occurrence of fog and haze. Statistics show that the number of precipitation days in autumn and winter has decreased since 1961.
4. Low air humidity
When haze occurs, the weather conditions are characterized by stable and dry air mass, and there are many days when such weather conditions are met in autumn and winter. It is found that the humidity in autumn and winter is small, and in the past 50 years, the autumn shows a significant downward trend, and the autumn and winter show more and more dry signs, which is conducive to the increase of haze days and the decrease of fog days.