Runaway ozone generation due to contamination of electrode surfaces is a limiting factor in the long-term effectiveness of electrostatic air cleaners. Modification of the form of the corona discharge, accompanied by a significant rise in current, is the cause of increased ozone levels. After one week of operation in filtered air containing Arizona Road Dust, ozone concentration in a laboratory air cleaner increases by 460 %. In this case, there is slight contamination on the discharge wires, but the ozone increase is attributed exclusively to back corona on the collection plates. On the other hand, oxidized discharge wires are believed to contribute to an order of magnitude increase in ozone concentration in a commercial air cleaner, operated in room air for 7-weeks. Wire contamination alone can increase ozone generation. An insulating tape adhesive applied to a 0.254 mm diameter stainless steel wire causes a 10-fold increase in ozone concentration.
Bibliographical noteFunding Information:
Paper MSDAD 92-83, approved by the Electrostatic Processes Committee of the IEEE Industry Applications Society and presented at the 1992 Industry Applications Society Annual Meeting, Houston, TX, USA. Manuscript approved for publication August 20, 1993. This work was supported by U.S. Environmental Protection Agency Grant R-81687W1 and by Teledyne Water Pik. Judy A. Dorsey is with Battelle Pacific Northwest Laboratories.