Basic Study of Indoor Air Quality Improvement by Atmospheric Plasma

Indoor air quality was improved by controlling particulate matter (PM) consisting of components such as house dust and bacteria, using an atmospheric pressure plasma. Two types of electrode, which generate corona discharges, were placed inside a reactor and energized to generate a nonthermal plasma, i.e., a disc-type reactor and a needle-type reactor. A plasma can decompose harmful substances by various active species such as reactive radicals (e.g., N*, O*, and OH*) and ions, and a strong electric field. The particle collection rate depended on the discharge voltage, number of mesh filters, flow rate, and reactor characteristics. The dust-collecting rate in the case of the disc-type reactor was 95% and in the case of the needle-type reactor was 98%. Formaldehyde removal was also performed to confirm the improved performance of the nonthermal plasma and reduction of formaldehyde to below the permitted value of 0.08 ppm.