Electrical mobility selector

PURPOSE: To provide a selector, which selects particles having a prescribed particle size from particles having an arbitrary particle size by electrical mobility of the particles, to select surely particles with the same orbit even for microparticles without loss by contacting with a disk wall. CONSTITUTION: An electrostatic selector of aerosol particles in an atmosphere has a first and a second parallel, spaced, coaxial conductive disks 18, 20, between which a disk establishing an electric field, an annular slot 22 made in the fist disk for communicating with the atmosphere to be examined, and a central intake 26 for bringing about a circulation of a filtered laminar air flow from the periphery of the disk are provided. Further, an annular or circular opening 28 made in the second disk, a third disk 32 facing the second disk, means for injecting filtered air flow between the second disk and the third disks from the surroundings a central pipe fixed to the third disk 32 for bringing particles having requisite electrical mobility to the outside of the apparatus are provided.