1, the air does not flow or the flow is not smooth, which is the main factor of smog. The air does not flow, so that tiny particles gather in the air. This is why the cold air and smog will dissipate when it comes.
2. A lot of polluted exhaust gas emitted by factory chimneys, smog can be summarized in one sentence: air pollution! These heavy industries are the main sources of pollution.
3. Automobile exhaust emissions. I wonder if you have noticed that there are more and more cars in the city, which can be seen from the number of parking spaces. The more cars, the more exhaust emissions, and the worse the natural air.
4, the humidity in the air is too low, people and cars will bring up the dust on the ground, which is a lot in construction sites. When you walk through a dusty place, a layer of floating dust will immediately appear under your feet.
Second, the harm to human body:
Because the diameter of fine powdery floating particles in smog is generally below 0.0 1 micron, they can directly enter bronchi and even lungs through the respiratory system. Therefore, the biggest impact of smog is the human respiratory system, and the diseases caused are mainly concentrated in respiratory diseases, cerebrovascular diseases, nasal inflammation and other diseases.
Extended data smog is composed of dust, sulfuric acid, nitric acid, organic hydrocarbons and other particulate matter 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 particle itself is not only a pollutant, but also a carrier of toxic substances such as heavy metals and polycyclic aromatic hydrocarbons.
The distribution of haze particles is relatively uniform, and the size of haze particles is relatively small, ranging from 0.00 1 micron to 10 micron, with an average diameter of about 1 ~ 2 micron. Floating particles are invisible to the naked eye. Because the smog is composed of dust, sulfuric acid, nitric acid and other particles, the longer the scattering wavelength, the more the light ratio, so the smog looks yellow or orange-gray.
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