NOVELTY - The water-proof and dust-proof membrane assembly comprises a body (11), and a supporting member (12). The body has an asymmetric porous structure (113) in the form of membrane having a first surface (111) and a second surface (112). The asymmetric porous structure has a thickness of 1-1000 mu m, a first porosity of 5-90%, a pore size of 0.01-15 mu m, a Frazier air permeability of 15x 104 to 250x 104 ft3/minft2, a Gurley number of 0.3-25 seconds, a water resistance of 11000-23000 mmH2O and sound transmission loss of 0.5-1.5 dB. The supporting member comprises a polymeric material.    USE - The water-proof and dust-proof membrane assembly is useful in an electronic device, lighting system and a container (all claimed), where the: electronic device includes digital camera, cell phone, MP3 player, earphone, microphone, speaker, radio, digital book, automobile backup radar, transceiver, projector, ink cartridge, battery box, outdoor lighting equipment, automobile lamp, LED lighting device, gas detector, medical electronic product, military-specific electronic product, underwater digital video camera, underwater digital camera, underwater MP3 player, underwater lighting apparatus and water-proof adapter; and container is Petri dish and a solar cell junction box.    ADVANTAGE - The water-proof and dust-proof membrane assembly exhibits improved sound transmission capability and air permeability, and excellent supporting intensity and water pressure resistance, and prolongs the service life and improves sensitivity of the electronic products.    DETAILED DESCRIPTION - The water-proof and dust-proof membrane assembly comprises a body (11), and a supporting member (12). The body has an asymmetric porous structure (113) in the form of membrane having a first surface (111) and a second surface (112). The asymmetric porous structure has a thickness of 1-1000 mu m, a first porosity of 5-90%, a pore size of 0.01-15 mu m, a Frazier air permeability of 15x 104 to 250x 104 ft3/minft2, a Gurley number of 0.3-25 seconds, a water resistance of 11000-23000 mmH2O and sound transmission loss of 0.5-1.5 dB. The supporting member comprises a polymeric material, and includes a first contact surface (121) and a second contact surface (122). A second porosity (10-99.99%) of the supporting member is larger than the first porosity. The first surface of the body and the first contact surface of the supporting body are bonded. The asymmetric porous structure includes a skin layer placed on the first and second surfaces, and a continuously foamed porous layer. The skin layer makes up 0.04-40% of the thickness of the asymmetric porous structure. A water contact angle of the skin layer is 120-135 degrees . The asymmetric porous structure is produced by heat-treating a symmetric porous structure. The variation of the Frazier air permeability of the asymmetric porous structure, after the heat treatment, is 1.1-2.5 times before the heat treatment. The collecting efficiency of the asymmetric porous structure is 99.50-99.99%. The water-proof and dust-proof membrane assembly using the asymmetric porous structure in which the skin layer is provided on the first surface side and the second surface side has a Frazier air permeability of 12.6x 104 ft3/minft2 to 220x 104 ft3/minft2, a Gurley number of 0.3-25 seconds, a water resistance of 13000-25000 mmH2O and a sound transmission loss of 0.7-3 dB. The body is formed by a film including a resin porous film or a fluorine polymer film. The resin porous film is an ultra-high molecular weight polyethylene porous film or a polytetrafluoroethylene film. The fluorine polymer film is a partially fluorinated polymer film or a completely fluorinated polymer film. INDEPENDENT CLAIMS are included for:    (1) an electronic device;    (2) a lighting system; and    (3) a container.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic sectional view of a waterproof and dust-proof membrane assembly.    Body (11)    Supporting member (12)    First surface of the body (111)    Second surface of the body (112)    Asymmetric porous structure (113)    First contact surface of supporting member (121)    Second contact surface of supporting member. (122)