Under normal circumstances, the composition of particulate matter is divided into three types: insoluble dry benzene, complex organic components, inorganic water-soluble components and water-insoluble components. The water-soluble components mainly include sulfates, nitrates, chlorides, etc.; the insoluble dry water components are mainly composed of oxides of elements such as silicon, aluminum, iron, calcium, magnesium, sodium, and potassium. If oily particulates refer to particulates such as kitchen fume and automobile exhaust, they are insoluble in water.
The composition of oil fume pollutants is complex, mainly including particulate matter and gaseous organic matter. The composition of oil fume is extremely complex, and there are more than 20 kinds of pyrolysis products of different kinds of edible oil at high temperature. There are mainly aldehydes, ketones, hydrocarbons, fatty acids, aromatic compounds and heterocyclic compounds. Different foods will produce different types of volatile substances at high temperatures, as many as hundreds of them.
Generally, the particle size of oil fume is between 0.01 micron and 0.3 micron, which belongs to floating dust with a particle size of less than 10 microns. It can float in the air or be directly inhaled by the human body. The HEPA in the HEPA filter is actually a filtration standard. That is, it has a filtration efficiency of more than 99.97% for 0.3-micron particles. In other words, the HEPA filter can filter out harmful substances such as oil fume, soot, automobile exhaust, and chemical smog in the air.