An air purifier has a lower base, an upper cover, and a middle sector in between to accommodate a blast component, a light-emitting element, a control unit, and a power supply base. The middle sector has an air intake, a passage, and an air outlet hidden inside the upper cover. The upper space of the upper cover has a fluid communication with the exterior via the air intake and a lower annular gap between the lower base and the middle sector. The upper space of the upper cover is connected to the accommodating space of the lower base via the passage. The accommodating space of the lower base has a fluid communication with the exterior via the air outlet and the upper annular gap between the middle sector and the upper cover.