What are the weather characteristics of smog?

Fog is a common disastrous weather phenomenon, and its occurrence is closely related not only to the weather system, but also to the underlying surface and topography. The formation of fog has a strong locality, and the conditions such as rich water vapor content in the atmosphere, relatively stable stratification in the near-surface air, warm air flowing through cold surface areas, or severe radiation cooling determine the formation of fog. According to the causes of fog formation, fog can be roughly divided into two categories: one is frontal fog, high pressure fog and low pressure fog under the influence of weather system; The other is advection fog, radiation fog and evaporation fog formed by the properties of the underlying surface. In addition, there is uphill fog affected by the terrain. Generally speaking, coastal areas, mountains and cities are frequently foggy areas. In China's inland areas, there are mostly radiation fog, and there are many advection fog in coastal areas. The uphill fog can often be seen on the windward slope of mountains, and frontal fog can often be seen in areas and seasons with frequent frontal activities. Fog occurs all year round in our country, and most areas are foggy in autumn and winter, with less fog in spring and summer.

Characteristics of haze

Haze has obvious seasonal changes in most parts of the country, and its basic characteristics are: more in winter, less in summer, and middle in spring and autumn. The weather conditions when haze occurs are characterized by a stable and dry air mass. In winter, there are many days to meet such weather conditions, and in some places, coal is used for heating, which is dusty and easy to form haze. In most parts of China, summer is rainy, local convection is strong, and rainfall is more abundant than other seasons, which washes away pollutants such as dust in the air, which is not conducive to the formation of haze weather.