Abstract: An air purifier includes a base, one or more filter units and a cover unit. The base has a housing, a blower, vents in the housing for the egress of air from the blower, a first channel providing ingress of air to the blower and a connector on the housing. One or more filter units attach to the base, each of which includes a filter unit housing, openings in the filter housing for ingress of air, a second channel providing air from the openings to the first channel and a filter media between the openings and the channel to filter the air. At opposing ends of the filter unit are connectors configured to matingly engage with the connector of an adjacent unit. The last filter unit mounted is engaged with a cover having a housing and another connector, wherein the connectors engage with a connector on an adjacent unit.

Abstract: A cartridge humidifier has a tubular, air permeable, water retentive or absorbent evaporator pad, a tubular, air permeable, generally rigid support for supporting the pad and for imparting strength and shape to the pad, and a tubular water distributor attached to the support for distributing water uniformly to the pad and for accommodating or inducing air flow transversely through the pad into the hollow core of the pad and support and for discharging moistened air axially through the hollow core of the distributor. The cartridge humidifier may also have one or more water reservoirs, a pump for transferring water form a reservoir to the distributor and thence to the evaporator pad, and a fan for inducing air flow transversely through the pad and axially out to the ambient through the hollow core.