Causes of haze weather

The causes of haze weather are: air pollutant discharge, weather conditions and geographical and climatic conditions.

1, air pollutant emission

The waste gas produced by industrial production, transportation, energy consumption and other activities contains a large number of pollutants, such as particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds and so on. After these pollutants are discharged into the atmosphere, they are easy to gather and form smog under certain meteorological conditions.

2. Meteorological conditions

Haze usually occurs in high pressure weather, cold high pressure and inversion temperature. Cold and high pressure weather will inhibit the rise of pollutants, form an atmospheric inversion layer, and make pollutants stay in the lower atmosphere. Such weather conditions will lead to the accumulation of smoke.

3. Geographical and climatic conditions

Urban geographical environment and climatic conditions will also affect the formation of smog. For example, the topography of the valley easily hinders air circulation, makes pollutants stay, and intensifies the formation of smog.

Composition of smoke:

Haze is composed of particles such as dust, sulfuric acid, nitric acid and organic hydrocarbons in the air. It will also make the atmosphere turbid, blur the vision and worsen the visibility. If the horizontal visibility is less than 65,438+00,000 meters, the sight distance obstacle caused by this non-aqueous aerosol system is called haze or dust haze, and the Hong Kong Observatory calls it haze.

Haze is mainly composed of sulfur dioxide, nitrogen oxides and inhalable particles. The first two are gaseous pollutants, and the last particulate matter is the main reason for aggravating smog weather pollution. Together with the fog, they make the sky gloomy in an instant. The abbreviation of particulate matter is PM, and Beijing monitors fine particulate matter (PM2.5), that is, pollutant particles with aerodynamic equivalent diameter less than or equal to 2.5 microns. This kind of particulate matter itself is not only pollutants, but also heavy metals, polycyclic aromatic hydrocarbons and so on.

The above contents refer to Baidu Encyclopedia-Smog