Abstract: An apparatus for collecting pollutants in which a passageway is formed to define a path for industrial gases passing therethrough. A plurality of isotope sources extend along at least a portion of the path followed by the industrial gases to provide a continuing irradiation zone for pollutants in the gases. Collecting electrode plates are associated with such an irradiation zone to efficiently collect particulates as a result of an electrostatic field established between such plates, particularly very small particulates. The series of isotope sources are extended for a length sufficient to attain material improvement in the efficiency of collecting the pollutants. Such an effective length is established along a substantially unidirectional path of the gases, or preferrably a reversing path in a folded conduit assembly to attain further efficiency by allowing more compact apparatus structures.