Dust refers to solid particles suspended in the air. Traditionally, there are many names for dust, such as dust, dust, smoke dust, mine dust, sand dust, powder and so on. These terms have no clear boundaries. The International Organization for Standardization (ISO) defines suspended solids with a particle size less than 75μm as dust. The existence of dust in the atmosphere is one of the main reasons for keeping the earth's temperature. Too much or too little dust in the atmosphere will have a disastrous impact on the environment. However, in life and work, productive dust is the natural enemy of human health and the main cause of many diseases. Source of dust: mechanical processing or crushing of solid substances, such as metal grinding, cutting, drilling, blasting, crushing, grinding, processing of agricultural and forestry products, etc. Dust particles, such as metal melting, welding and casting. It is formed by condensation or oxidation of steam generated when a substance is heated in air.
Particles formed by incomplete combustion of organic substances, such as smoke and dust produced by combustion of wood, oil and coal. It is also the deposited dust floating in the air again (producing secondary dust) during the operations of casting turning, throwing, sand cleaning, screening, packaging and handling, and the deposited dust produced by vibration or airflow movement. Dust is almost everywhere. After weathering, soil and rocks split into many tiny particles, which float in the air with pollen, spores and other organic particles. In addition, a lot of dust is a by-product of industrial and transportation development; The exhaust gas from chimneys and internal combustion engines also contains a lot of dust, flour and volcanic ash from quarry operations. In addition, dust will pollute buildings and corrode valuable ancient buildings. Dust falling on plant leaves will hinder photosynthesis and inhibit its growth.