Filtration process in a fibrous filters with a packing density of range 10(-4) at th, presence of external electric field of intensity up to 2.5 kV/cm was investigated. The velocity of aerosol particles was varied from 2 to 20 cm/s. Results show the substantial decrease of penetration from 90% to 10% in a case of application of electric field. The pressure drop of gas flow through filter was order of few Pascals. Filtration systems analyzed in this paper can be used as prefilters in the case of high concentration of particles in a filtrated gas.