How many layers does an air purifier filter generally contain? What are they?

Air purifier filters generally contain three layers of filters. The first layer is pet cotton, which is mainly used to filter large particles and prevent damage to the second and third layers. The filter screen, the second layer filter screen is generally a hepa filter screen, which is used to remove PM2.5, which many users are more concerned about. The third layer filter screen is generally an activated carbon filter screen to remove formaldehyde and benzene series. It should be noted that the larger the CCM value, the longer the life of the filter, so when you choose an air purifier filter, you should choose a product with a larger ccm value. In addition to filters, there are also some foreign brands of air purifiers such as koocent, which also add things like UV germicidal lamps to remove viruses from the air, which is very useful in public places. If it is a family environment and there are frail people at home, using this properly can also avoid virus infestation.