Air filter, air filtration unit and air filtration system

The invention discloses an air filter, an air filtration unit and an air filtration system. A filtering channel is formed inside the air filter main body. A chemical substance filter layer and a particle filter layer are arranged adjacent to each other in the filter channel. The chemical substance filter layer is used for filtering chemical substances, and the particle filter layer is used for filtering particles. Air successively passes through the chemical substance filter layer and the particle filter layer. The air filtration unit comprises the above air filter. The air filtration system comprises the above air filtration unit. By the air filter, the air filtration unit and the air filtration system, the technical problem that effect of an air filter in the prior art is single, dimensions of an air filtration unit and an air filtration system are large and arrangement and installation are inconvenient is solved.