Panasonic Conducts Fundamental Study on Inactivation of Surface-Adhered Viruses Using Gaseous Hypochlorous Acid in Actual Occupied Indoor Environments

Osaka, Japan – Panasonic Corporation (https://holdings.panasonic/global/) announced that its Heating & Ventilation A/C Company (hereinafter referred to as Panasonic) conducted a fundamental study on the inactivation of surface-adhered viruses using gaseous hypochlorous acid in actual occupied indoor environments*¹. In this study, Influenza A virus (H1N1) (hereinafter referred to as “influenza virus”) and Echovirus type 30 (E30)*² (hereinafter referred to as “echovirus”) were used, and respectively, the inactivation rates of 99.9% and 99.0% were observed*³.

For approximately 40 years*⁴, Panasonic has been researching hypochlorous acid technology and confirmed numerous effects in suppressing bacteria and viruses. In addition to this long-accumulated body of evidence, Panasonic began industry-academia collaboration last year to advance verification aimed at reducing actual infection risks in humans. With the goal of creating “infection-controlled space” where people can live safely and with peace of mind by lowering infection risks, the company expanded its focus merely “suppressing causative agents of diseases” to “suppressing the diseases themselves.” In January 2025, for the first time in the industry, Panasonic conducted a fundamental study on the inactivation effects of airborne and surface-adhered bacteria using hypochlorous acid in classrooms and a training room at Gunma Paz University*⁵.

Following last year’s study on bacteria, this research was conducted in a training room*⁶ at Gunma Paz University, where a fundamental study was carried out on the inactivation effects of gaseous hypochlorous acid on clinically derived strains of influenza virus and echovirus that had been applied to culture plates. An experimental device that generates and volatilizes a hypochlorous acid aqueous solution was installed in a training room of approximately 56 tatami mats in size. After 24 hours, samples exposed to gaseous hypochlorous acid showed inactivation rates of 99.9% for influenza virus and 99.0% for echovirus, compared with natural decay in the control samples.

*1 This study involved experiments on viruses and did not evaluate the effectiveness against actual diseases.

*2 A type of virus that can cause illnesses such as meningitis.

*3 This is a fundamental study and does not constitute performance verification using products equipped with hypochlorous acid aqueous solution.

*4 Including SANYO Electric Co., Ltd.

*5 https://news.panasonic.com/global/press/en250116-2

*6 A room that meets Biosafety Level 2 (BSL-2) standards for the safe handling of viruses.

• Testing Organization: Panasonic Corporation
• Experimental Organization: Gunma Paz University
• Experimental Device: A device in which a rotating sterilization filter is impregnated with a hypochlorous acid aqueous solution of approximately 100 mg/L, and a constant airflow (5.6 m³/min) is directed onto the filter to volatilize gaseous hypochlorous acid.
• Target Viruses: Influenza A virus (H1N1), Echovirus type 30 (E30)
• Experimental Duration: 24 hours
• Experimental Space: Unoccupied training roomRoom size: Approx. 260 m³ (approx. 56 tatami mats)
  Facility conditions: No ventilation; air conditioning availableTemperature:
  18.6–23.3°C (with gaseous hypochlorous acid)
  18.8–23.0°C (without gaseous hypochlorous acid)Humidity:
  49–76% RH (with gaseous hypochlorous acid)
  22–72% RH (without gaseous hypochlorous acid)
• Experimental Method:
  • Experimental Device Conditions
    With gaseous hypochlorous acid
    Without gaseous hypochlorous acid (natural decay)
  • Inoculation Method
    100 μL of each virus suspension was applied to culture plates (Petri dishes).
  • Placement of Culture Plates
    With gaseous hypochlorous acid: Placed on a desk 8 m away from the experimental device (0.8 m above the floor).
    Without gaseous hypochlorous acid: Placed on a desk 8 m away from the experimental device, inside a container (approx. 16 L) that prevented exposure to gaseous hypochlorous acid (0.8 m above the floor).
  • Measurement of Viral Infectivity
    Cytopathic effect (CPE) caused by viral proliferation was observed under a microscope, and viral infectivity (TCID₅₀/mL) was calculated using the Spearman–Karber method.
    The inactivation rate was evaluated by comparing the condition without gaseous hypochlorous acid exposure versus with exposure, and statistical significance was assessed using the Mann–Whitney U test.
• Concentration Distribution of Gaseous Hypochlorous Acid
  • Concentration Distribution: Using the analysis software STREAM V2025.1, a simulation was conducted to confirm that gaseous hypochlorous acid disperses throughout the entire experimental space
  • Validity of the Simulation: It was confirmed that the simulated distribution matches the measured concentrations of gaseous available chlorine.
• Experimental Results: Significant inactivation of viruses by gaseous hypochlorous acid was confirmed.

*This study does not guarantee the efficacy or performance of any product.

Hypochlorous acid is a well-established and historically proven disinfectant, commonly used for chlorination in tap water. It is a powerful oxidizing agent that sterilizes and deodorizes by oxidizing—suppressing the activity of—bacteria and odors through electron removal. Among hypochlorous acid molecules (HOCl), the Cl+ ion exerts strong oxidative decomposition power by stealing electrons from other substances.
Hypochlorous acid solution is generated by electrolyzing saline water. The gaseous hypochlorous acid volatilized from the solution has a half-life of over 50 hours, making it highly resistant to self-decomposition and capable of diffusing over long distances.