The electret-treated sheet includes: a core layer (A) which is a porous film containing at least a thermoplastic resin; a surface layer (X) disposed on one side of the core layer (A); and a back surface layer (Y) disposed on the other side of the core layer (A), the surface layer (X) and the back surface layer (Y) each having a charged outermost surface, wherein the electret-treated sheet has a water vapor permeability coefficient of 0.1 to 2.5 g.Math.mm/m.sup.2.Math.24 hr; the core layer (A) has a pore aspect ratio of 5 to 50 and an average pore height of 2.5 to 15 μm; the surface layer (X) and the back surface layer (Y) each have a thickness of 5 to 200 μm; and the surface layer (X) includes a heat seal layer (B) including the outermost surface, wherein the heat seal layer (B) has a melting point of 50 to 140° C.

The electret-treated sheet includes: a core layer (A) which is a porous film containing at least a thermoplastic resin; a surface layer (X) disposed on one side of the core layer (A); and a back surface layer (Y) disposed on the other side of the core layer (A), the surface layer (X) and the back surface layer (Y) each having a charged outermost surface, wherein the electret-treated sheet has a water vapor permeability coefficient of 0.1 to 2.5 g.Math.mm/m.sup.2.Math.24 hr; the core layer (A) has a pore aspect ratio of 5 to 50 and an average pore height of 2.5 to 15 μm; the surface layer (X) and the back surface layer (Y) each have a thickness of 5 to 200 μm; and the surface layer (X) includes a heat seal layer (B) including the outermost surface, wherein the heat seal layer (B) has a melting point of 50 to 140° C.

The present disclosure provides filters that can be removed from surfaces without damage by having reduced or eliminated contribution of a core backing to peel force generated by the adhesive during removal. In some instances, this can be accomplished by a core that loses structural integrity in a direction normal to a plane defined by a major surface. In other instances, the contribution is reduced by compromising the interface between the core and a peelable adhesive layer.

It is provided that an electret having excellent filtering performance and a filter using the electret even in a case where polyolefin resin and magnesium element are contained. An electret comprising a polyolefin resin and a nitrogen-containing compound, wherein 0.1 to 5 parts by mass of the nitrogen-containing compound is contained to 100 parts by mass of the polyolefin resin, a proportion of a magnesium element contained in the electret is 5 to 100 ppm, and a QF value represented by the following formula is not less than 1.00 mmAq.sup.−1 when particles having particle diameters of 0.3 to 0.5 μm are to be collected.

QF [mmAq.sup.−1]=— [1n (particle penetration (%)/100)]/[ventilation resistance (mmAq)]

Disclosed is an engine exhaust dust removing system and method. The engine exhaust dust removing system involves an exhaust dust removing system inlet, an exhaust dust removing system outlet and an exhaust electric field device. The engine exhaust dust removing system has a good dust removing effect, and can effectively remove particulate matter from engine exhaust gas.

An engine exhaust gas treatment system, comprising an exhaust gas dust removal system and an exhaust gas ozone purification system. The exhaust gas dust removal system comprises an exhaust gas dust removal system inlet, an exhaust gas dust removal system outlet, and an exhaust gas electric field apparatus (1021). The exhaust gas electric field apparatus (1021) comprises an exhaust gas electric field apparatus inlet, an exhaust gas electric field apparatus outlet, an exhaust gas dust removal electric field cathode (10212), and an exhaust gas dust removal electric field anode (10211). The exhaust gas dust removal electric field cathode (10212) and the exhaust gas dust removal electric field anode (10211) are configured to produce an exhaust gas ionized dust removal electric field. The engine exhaust gas treatment system is able to effectively remove particles in engine exhaust gas, and the purification treatment effect for engine exhaust gas is good.

An air dust removal method, comprising the following steps: 1) using an ionization dust removal electric field to adsorb particulate matters in intake air; and 2) using the ionization dust removal electric field to charge an intake air electret element. The method can effectively remove dust in air, the dust removal ability is better, and the dust removal efficiency is higher.

Apparatus for reducing the translucence or opacity caused by smoke within a closed environment includes a fibrous substrate comprising non-conductive fibers. The apparatus further includes elongated, substantially parallel electrodes disposed on the substrate arranged as one or more pairs of adjacent electrodes, wherein a discharge gap is defined between each pair. The apparatus additionally includes a component configured for applying a voltage between each pair to generate a non-thermal microplasma in a corresponding discharge gap to collect or bind one or more airborne particulate combustion byproducts.

An imaging system includes a fixing device, a collection device, and a controller. The collection device collects ultrafine particles (UFP) emitted by the fixing device. The collection device includes an ionizer. The controller turn on the ionizer.

An air dust removal system (101) includes a dust removal system inlet (1011), a dust removal system outlet, and an electric field apparatus (1014). The electric field apparatus (1014) has an electric field apparatus inlet, an electric field apparatus outlet, a dust removal electric field cathode (10142), and a dust removal electric field anode (10141); the dust removal electric field cathode (10142) and the dust removal electric field anode (10141) are used for generating an ionization dust removal electric field. When dust is collected in the ionization dust removal electric field, the electric field apparatus (1014) detects an electric field current. The air dust removal system (101) can effectively remove particulate matters in air.