A system and method is provided for filtering water using a pre-filter and a primary filter, both removably disposed within a housing. The pre-filter is placed in series with the primary filter. The pre-filter includes a cavity within which the primary filter may be at least in part disposed. In one embodiment, the pre-filter and the primary filter are each removably received within the housing, so that either or both of the pre-filter and primary filter may be easily removed from the housing and replacement filters provided. Thus, a simple, convenient, compact filtering apparatus is provided.

A diffusive air purifier includes an air permeable container containing a chemical sorbent or a sorbent precursor. The sorbent has a chemical composition selected to achieve removal of an air pollutant via a chemical reaction that renders the predetermined air pollutant immobile. A method of manufacturing the diffusive air purifier includes impregnating a porous solid with a solution of sorbent precursor and a binding agent and drying the porous solid. A method of purifying indoor air includes detecting a measured concentration of an airborne chemical in an enclosed location; selecting the diffusive air purifier to adsorb the airborne chemical; and placing the diffusive air purifier in the enclosed location. Air diffuses through the outer container and into the sorbent where the chemical to be removed is retained. Air, free of the target chemical, diffuses out of the container and the process repeats.

A water filtration system with replaceable active components. The water filtration system includes an outer housing, an inner filter canister, and a housing cap. The outer housing includes an inlet opening and an outlet opening. The housing cap includes a cap inlet opening. The inner filter canister filters water entering through the cap inlet opening. The outer housing retains and holds replaceable active filter components. The outer housing retains and holds the inner filter canister within the outer housing. The inner filter canister includes a connector for coupling to a connector on the underside of the housing cap. The housing cap engages with the inlet opening to secure the inner filter canister and the active filter components within the outer housing. Water exiting from the inner filter canister will be further filtered by the active filter components before exiting the outer housing via the outlet opening.