What is Air Filter

i think it will be bored if there is no picture to show you on the filter unit. Briefly as below,it is the whole range of air filtration system.













Air filtration is divided into primary filters, secondary filters, Semi HEPA filters, HEPA filters, ULPA filters and SULPA filters. The separation of filters is depend on the standard of you referring. There are ASHRAE standard, IEST standard, EN standard, JIS standard and others.