What is the symbol of fog?

Meteorological symbols of fog and haze, the fog with water content as high as 90% is three horizontal bars, and the haze with water content below 80% is marked as "8", which looks a bit like an infinite symbol in mathematics.

When the water content is between 80% and 90%, it is a mixture of fog and haze, but generally speaking, the main component is haze.

The main source of smoke

First: it's automobile exhaust. Large vehicles that use diesel are "recidivists" who emit PM 10, including buses, shuttle buses of various units and large transport trucks. Sources of toxic particulate matter in cities: firstly, automobile exhaust. Cars that use diesel are "habitual criminals" who emit particles. Small cars that use gasoline emit gaseous pollutants, such as nitrogen oxides, which are easily converted into secondary particulate pollutants in foggy days, aggravating smog.

Vehicle exhaust is the main component of smog particles. According to the latest data, motor vehicle exhaust accounts for 22.2%, coal combustion accounts for 16.7%, dust accounts for 16.3%, and industry accounts for 15.7%. However, with the development of automobile technology and the improvement of oil quality, environmental managers have found that motor vehicle exhaust does not play a decisive role in the formation of haze weather. However, as some cities with large car ownership, managers still need to control vehicle emission standards to avoid the formation of haze weather.

Second: the waste gas produced by burning coal for heating in winter in the north.

Third: the waste gas emitted by industrial production. For example, metallurgy, kilns and boilers, electromechanical manufacturing, automobile repair and paint and building materials production produce a lot of waste gas from kiln combustion.