Air pollution is among many hazardous problems that challenges mankind in areas such as sanitation, health and economy. The root of pollution which causes health problems and even terminal diseases is mainly related to the level of industrialization of the any concern society. Thus pollution control is vitally important. There are various solutions that can be employed to control pollution, but the most effective way to implement this task is to prevent pollution of the environment. Use of filter media and filtration systems form the most widely means of pollution control. Generally textile fabrics are the most extensive materials used as filter media. Historically woven fabrics have been used in dry and liquid filtration; nonwoven fabrics and in particular needled fabrics due to their technical and economical advantages are being used extensively in dry filtration. Versatility in manufacturing process and possibility of electrical charging of the nonwovens provides an effective means for arresting most of contaminants. The application of electric field forms the basis of what is known as electrostatic filtration. Electrostatic filtration media encompass a broad justify; TEXT-INDENT: 0.3in; MARGIN: 0in 0in 0pt; mso-line-height-alt: .7pt" Numerous studies have investigated conditions and parameters that affect the performance of Electret filter media. Charging methods, environmental conditions such as temperature and relative humidity, duration of charging and percentage of fibers in a mixture are parameters that have been discussed earlier by other researchers. In this study the effects of fineness and crimp of Polypropylene fibers and the porosity of the fibrous nonwoven layer on air permeability, filtration efficiency and charge ability of media were investigated. The charge ability of new and used media was compared and the relationship between that and filtration efficiency is discussed. Results showed a dramatic decrease in air permeability of media over fiber fineness raise. Air permeability rose gradually when fiber crimp got doubled. The decrease in fiber fineness reduced filtration efficiency of media sharply. Fiber crimp had not specific effect on filtration efficiency. The charge ability of media went up gradually by fiber fineness raise. Used filter media showed more charge ability compared with new media. Keywords : Filter, Electrostatic, Fineness, Crimp, Efficiency, Air permeability, Charge ability, Polypropylene.
