Air Purifiers : An Introduction Air Purifier is a device that cleans the polluted air and is capable of effectively removing bacteria, viruses and particulate matter present in the air. Air purifiers are different from air cleaners in their application, size, cost and area of purification. There are mainly four types of air purifying technologies used in air purifiers which are described below. High-Efficiency Particulate Arrestance (HEPA): Air purifier integrated with HEPA filters comprises a stack of fibers that eliminate allergens and other airborne particles of 0.3 micrometers, with an efficiency of 99.97%. Electrostatic Precipitator: Air purifier with electrostatic precipitator removes contaminants by electrostatic discharge produced by alternately charged plates arranged in its filters. Activated Carbon Filter: These air purifiers are made up of absorbent filters, which are capable of absorbing pollutants, trapping impurities inside and releasing pollutant free air. Ion & Ozone Generator: It contains an ionizer that generates high electric field by ions. The positive and negative ions attract other charged particles in the polluted air and release fresh air into the environment. 6