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(2) The particle size of the dust. Dust particle size refers to the size of the dust particle size. In general, the smaller the dust particles, the greater the harm to people.
(3) Dispersion of dust. The degree of dust dispersion refers to the percentage of dust particles of various grain sizes in the overall composition of the dust. In the dust composition, the larger the percentage of dust particles smaller than 5um, the greater the harm to humans.
(4) The concentration of dust. The concentration of dust refers to the amount of floating dust contained in a unit volume of air. The higher the dust concentration, the greater the harm to the human body.
(5) Adsorption of dust. The adsorption capacity of dust is closely related to the surface area of ​​dust particles. The larger the dispersion, the larger the surface area and the enhanced adsorption capacity. The main indicators are hygroscopicity and toxicity.
(6) The chargeability of dust. Dust particles can carry electric charge. The source is that coal rock is charged by friction during pulverization, or it is charged by collision with ions in the air. The amount of dust particles depends on the size of the dust particles and is related to temperature and humidity. When the amount of electricity is increased, the amount of charge is reduced when the humidity is increased.
(7) Combustion and explosiveness of coal dust. When coal dust reaches a certain concentration in the air, it can be burned and exploded under the ignition of an open flame.
The concept and nature of dust
First, the concept of dust
(1) All dust. Full dust refers to the collection of all solid particles suspended in the air for a certain period of time by a general open sampler.
(2) Respirable dust. Respirable dust refers to floating dust that can be absorbed into the lungs of the human body and stay in the alveolar region. Very fine dust with aerodynamic diameter less than 7.07um is the main dust causing pneumoconiosis.
(3) Floating dust and falling dust. The dust suspended in the air is called floating dust, and the dust deposited on the top of the roadway, the gang, the bottom plate and the object is called dust.
Second, the nature of dust
(1) The content of free silica in the dust. The content of free silica in dust is the decisive factor that harms the human body. The higher the content, the greater the harm. Free silica is a major cause of silicosis.
(8) Floating dust and falling dust. The dust suspended in the air is called floating dust, and the dust deposited on the top of the roadway, the gang, the bottom plate and the object is called dust.