Cabin filters have a filtering medium made entirely from synthetic fabric. Excellent efficiency in filtering particles of sizes smaller than 1m results from the effect of contaminants attraction by electro statically loaded fibres. Due to this effect, contaminants of sizes smaller than pores in the filtering medium maybe efficiently trapped. Smaller particles simply get stuck to fibres. Once they come close, the electrostatic attractive force is stronger than the force of particles flow caused by the air blast. Synthetic fibres are slightly hygroscopic, so dust filters do not get deformed from water. They also have antiseptic properties (they are not favourable to microorganisms), and therefore are efficient in stopping microorganisms development and organic contaminants decomposition in the filter during exploitation period.