What is the icon symbol of fog?

As shown in the figure below:

The meteorological symbols of fog and haze. Fog with a moisture content of up to 90% has three horizontal bars, while haze with a moisture content of less than 80% , it is marked as a lying "8", which looks a bit like the infinity symbol in mathematics.

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

The main source of smog

First: car exhaust. Large vehicles using diesel are "heavy offenders" of PM10 emissions, including large buses, shuttle buses of various units, and large transport trucks. Sources of toxic particulate matter in cities: First, car exhaust. Diesel vehicles are "heavy offenders" of emitting fine particulate matter. Although small cars using gasoline emit gaseous pollutants, such as nitrogen oxides, they can easily be converted into secondary particulate pollutants in foggy weather, aggravating smog.

Motor vehicle exhaust is the main component of smog particles. The latest data shows that motor vehicle exhaust accounts for 22.2% of Beijing’s haze particles, coal burning accounts for 16.7%, and dust accounts for 16.3%. Industry accounts for 15.7%. However, with the advancement of automobile technology and the improvement of oil quality, environmental managers have found that vehicle exhaust does not play a decisive role in the formation of haze weather. However, as some cities with a large number of cars, managers still need to control vehicle emissions. standards to avoid the formation of haze weather.

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

Third: Waste gas emitted from industrial production. For example, metallurgy, kilns and boilers, mechanical and electrical manufacturing, as well as a large number of exhaust gases emitted from the combustion of kilns for auto repair painting and building materials production.