Performance evaluation of a non-thermal plasma-based corona discharge system with high electric field intensity for airborne pathogen removal

Abstract

This study examines a corona discharge system that produces non-thermal plasma using a high intensity electric field established between a flat plate and a sharp-pointed electrode. The plasma conditions contributed to the generation of reactive chemical species, especially ozone (O<inf>3</inf>) and nitrogen oxides (NO<inf>X</inf>), acknowledged for their potent antimicrobial properties. Controlled laboratory experiments occurred using Bacillus subtilis spores as a standard biological indicator organism to assess sterilization efficacy because of their established resistance and safety for laboratory applications. The results demonstrated a clear correlation between electric field intensity and the concentration of reactive species. In the Electric Field Strength regime (1136.36kV/m), O₃ and NOₓ concentrations attained 9.40 ± 0.19 ppm and 23.98 ± 1.30 ppm, respectively, resulting in 98.99 % inactivation of B. subtilis within 5 min and total sterilization (100 %) within 10 min at an airflow rate of 40 L/min. The findings illustrate the capability of corona discharge-based plasma systems as safe, residue-free, and environmentally sustainable methods for real-time air disinfection in enclosed, high-risk conditions.