How does haze weather form?

The reasons for the formation of haze weather are as follows:

1. Sulfur dioxide, nitrogen oxides and inhalable particulate matter are the main components of haze. The first two are gaseous pollutants. The last particulate matter is the main culprit that aggravates haze weather pollution. They combine with the fog, making the sky instantly gray. The English abbreviation of particulate matter is PM, and the current high-frequency vocabulary PM2.5 in the air refers to pollutant particles with a diameter less than 2.5 microns. The particles themselves are both a pollutant and a carrier of toxic substances such as heavy metals and polycyclic aromatic hydrocarbons.

2. Sources of toxic particulate matter in cities: The first is car exhaust. Large vehicles using diesel are "heavy offenders" of emitting fine particulate matter, including large buses, shuttle buses of various units, and large transport trucks. 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.

3. It is the waste gas produced by burning coal for heating in winter in the north.

4. It is waste gas emitted from industrial production. For example, there are industrial kilns and boilers in the metallurgical and mechanical and electrical manufacturing industries, as well as a large amount of exhaust gases emitted by the combustion of kilns for auto repair painting and building materials production.

5. Dust generated by construction sites and road traffic.