An air intake includes an air channel for an air stream passing through the air intake into the plant, and a particle filter assembly arranged in the air channel for removing particles from an air stream passing through the air channel, the particle filter assembly including a front and a back filter unit. The front filter unit is arranged before and in series with the back filter unit such that an air stream passing through the air channel passes through the front filter unit before passing through the back filter unit. The front filter unit is removable and replaceable by a fresh front filter unit while the back filter unit remains in the air channel and while an air stream is passing through the air channel during operation of the plant. The front filter unit has at least equal efficiency and dust holding capacity as the back filter unit.