Effect of Nonthermal Plasma Technology on Reducing Airborne Contaminants in an Indoor Setting

Abstract A variety of air cleaning technologies have been used to reduce airborne contaminants consisting of particulates and gaseous pollutants in an indoor environment over the past several decades. Air cleaning technologies have the potential of assisting low-cost fibrous media to clean contaminated indoor air and reduce building ventilation rates to conserve energy. Air cleaning technologies including plasma air ionization, photocatalytic oxidation, sorption, ultraviolet, electrostatic precipitator, high-efficiency particulate air (HEPA), activated carbon, etc. are employed to reduce, capture, or eliminate airborne contaminants. The plasma air ionization method generally turns electrically neutral air into negative or bipolarized air ions by applying an electric charge to the indoor air to produce a clean indoor air environment. There are two types of plasma ionization: nonthermal ionization and thermal plasma ionization. Nonthermal plasma ionization includes dielectric barrier discharge (DBD) and needlepoint bipolar ionization (NBI). A growing body of recent evidence has presented the potential of using bipolar air ionization to remove airborne particles and gaseous pollutants, and to decrease bacterial deposition on surfaces, inactivate airborne bacteria, viruses, and fungi. Meanwhile, NBI is where the ions are emitted into the airflow by needles or carbon brushes or other needlepoint-type emitters while DBD bipolar ionization uses a sealed cathode tube to create a plasma discharge which will then emit ions into the airflow. The present work particularly studies the effect of DBD bipolar ionizer-assisted minimum efficiency reporting value (MERV) filter technology on reducing airborne contaminants including particulates and toxic gases.