Abstract: A metal foam-based filtration system and method for removing sub-micron particles and contaminants from a gas or fluid flow with the use of ultralow density metal nanowire meshes that have nanometer to micron scale pores for trapping air/fluid-borne particulates. Filters can use metal foams and coated metal foams alone or in tandem. The size and density of pores in the foam can be adjusted with synthesis conditions. Foams with pore size gradients promote the trapping of different sized particulates at different regions of a foam. Multiple rounds of electrodeposition may be applied to increase the surface area and curvature of a nanowire mesh and strengthen the mesh to make it self-supporting, free-standing and capable of supporting a much heavier mass without collapse. A metal and/or a coated metal foam can act as a catalyst or substrate for absorption or adsorption to capture target particles and/or contaminants.