Properties of filtering materials used as porous barriers in filter elements of motor vehicle air cleaners have been analyzed. Criteria of fiber and paper selection for the filter elements have been presented. A relation showing the filter life and a coefficient of dust absorption km of filtering materials have been presented. A methodology of research of the fiber filter element characteristics has been developed. Results of investigations of the characteristics of efficiency, filtering accuracy and drag of the filtering fiber operating at different filtering rates have been presented. The coefficients of dust absorption km of the filtering fiber have been determined. Changes in the granulometric properties of dust in the airflow downstream of the filtering fiber and paper have been presented.