Electrostatic filters do NOT use any physical filter material such as paper, cloth, fibre etc., to capture fine particles, but uses a high voltage electrostatic charge between a series of aluminium plates instead, to first charge floating particles as small as 0.01 micron (1 micron is 125, 400th of an inch ). These positively charged particles are subsequently collected on negatively charged aluminium plates, and the clean air , devoid of particles is sent out of the filter . The efficiency is between 95% to 100% for various particulates. The main advantages of Electrostatic Filters are :