Development of a plasma-based air treatment device for densely populated areas

The persistent challenge of airborne pathogens in densely populated indoor environments calls for efficient and reliable air sterilization solutions. This study presents a compact three-electrode Double Dielectric Barrier Discharge (DDBD) plasma module for sterilizing contaminated airflow, achieving up to 83% microbial inactivation at 9.3 kV and 10.3 kHz. While effective, the plasma discharge produced reactive byproducts, notably ozone (up to 46.21 ppm) and nitrogen oxides (NOₓ), at levels exceeding health-based safety thresholds. To mitigate these emissions, a four-stage byproduct control strategy was developed, including a MnO₂ catalytic mesh for ozone decomposition, a UV-activated TiO₂ photocatalytic stage for NOₓ reduction and enhanced sterilization, an upgraded 15 mm activated carbon bed for residual adsorption of NOₓ and volatile organic compounds, and a feedback-controlled electrochemical sensor to monitor byproduct levels and dynamically adjust plasma power. The modular design facilitates integration into existing filtration frameworks, providing a scalable and practical solution for indoor air treatment in high-traffic settings such as hospitals, schools, and transport hubs.