Quantitative evaluation of H₂O₂ disinfection efficiency in air duct: Effects of temperature, relative humidity and H₂O₂ concentration

Hydrogen peroxide (H₂O₂) is widely used for disinfection because of its oxidative and antimicrobial properties. However, most studies have focused on surface disinfection, with limited research addressing its effectiveness for air disinfection. In this study, we developed a controlled air duct testing system to evaluate the disinfection performance of H₂O₂ in a ventilation system while precisely regulating environmental parameters. A sensitivity constant (Z) was introduced to quantitatively assess disinfection efficiency, with increased Z-values indicating enhanced disinfection performance. With a 7.5 s flow in the air duct system, the bioaerosol removal efficiency ranged from 26% to 97% under different temperature and humidity conditions. As temperature increased from 15 to 33 ℃, removal efficiency of Serratia marcescens and Escherichia coli increased from 40% to 95% and 78% to 97%, respectively. Correspondingly, Z-values increased from 0.0021 to 0.0076 ppm⁻¹s⁻¹ for S. marcescens and from 0.0072 to 0.0083 ppm⁻¹s⁻¹ for E. coli, suggesting that elevated temperature enhanced H₂O₂’s air disinfection efficiency. Conversely, higher humidities reduced H₂O₂’s efficacy; as the relative humidity decreased from 80% to 30%, the relative concentration of E. coli decreased and the Z-value dropped from 0.017 to 0.0022 ppm⁻¹s⁻¹. When the H₂O₂ concentration increased, the removal efficiency increased slightly, while the Z-value decreased significantly, indicating diminishing returns at higher H₂O₂ concentrations. These findings provide important insights for optimizing H₂O₂-based air disinfection strategies.