Active Chlorine Component of Hypochlorous Acid Solution Volatilized in the Air^(*1) Suppresses Over 99% of RS Viruses

Osaka, Japan – Panasonic Corporation (https://holdings.panasonic/global/) today announced that its Heating & Ventilation A/C Company (hereinafter referred to as Panasonic) verified that the active chlorine component volatilized from the hypochlorous acid solution, produced by electrolysis of salt water, effectively suppresses over 99% of respiratory syncytial viruses (RS viruses) adhered in a space of approx. 25 m³ within 8 hours^(*2).

The hypochlorous acid solution is produced through the electrolysis of salt water and demonstrates high efficacy in sterilization and deodorization. Since adopting the hypochlorous acid solution for the hygiene maintenance system of cup-dispensing vending machines in 1987^(*3), Panasonic has been researching hypochlorous acid technology for approximately 40 years. The company verified in the past few years that the solution is effective in suppressing viruses, including the influenza virus (H1N1), novel coronavirus (SARS-CoV-2) Omicron variant, and enterovirus and coxsackievirus, which can cause hand-foot-and-mouth disease, as well as herpangina.

RS viruses are major pathogen responsible for bronchiolitis and pneumonia, particularly known for causing severe illness in infants and the elderly. The viruses are primarily transmitted through contact with respiratory secretions from infected individuals or via airborne droplets released during coughing or sneezing. Upon infection, individuals may exhibit symptoms such as fever, nasal discharge, and coughing. In more severe cases, the condition may progress to wheezing and difficulty breathing.

Based on the current verification results, the active chlorine component volatilized from the hypochlorous acid solution is expected to suppress RS viruses adhered to tables, railings, and other objects.

[Figure 1. Infectivity titer of viruses by time elapsed]

■Verification method
Two cases were verified: one by soaking the rotary sterilization filter in a hypochlorous acid solution of approx. 150 mg/L, exposing the filter to a given amount of wind (3.8 m³/min) to volatilize the active chlorine component, and then exposing RS viruses-attached samples to the volatilized substance; and the other by not exposing the specimens to the active chlorine component (natural attenuation).

■Verification results
The effect of suppressing over 99% of RS viruses within 8 hours was confirmed (Figure 1).

*1: Solution made by electrolysis of salt water

*2: These verifications were conducted for basic research purposes and did not involve any products containing the hypochlorous acid solution.

*3: Including the SANYO Electric Co., Ltd.

[Details of Verification]

image: External view of the test chamber measuring 25 m3

Verifying organization: Panasonic Corporation
Testing organization: Kitasato Research Center for Environmental Science
Verification device: The rotary sterilization filter was soaked in a hypochlorous acid solution of approx. 150 mg/L and was exposed to a specified amount of wind (3.8 m³/min) to volatilize the active chloride component.
Verification method
• Exposure time: 0 to 12 hours (Exposure [with the verification device] / Non-exposure [no verification devices])
• Test space volume
Exposure: Approx. 25 m³ without ventilation
Non-exposure (natural attenuation): Approx. 25 m³ without ventilation

[Placement of viruses (exposure)]
• Placement of RS viruses-attached samples
Drop a specified amount^(*4) of test virus liquid onto each petri dish, and air-dry the liquid for about 20 minutes in airtight container with desiccant inside. Place RS viruses-attached samples 1.5 m away from the verification device (1.2 m above the floor).

*4: 2 μL x 110 spots (total 220 μL)

[Placement of viruses (non-exposure)]
• Place RS viruses-attached samples inside a test chamber of approx. 25 m³.

Exposure method
Place RS viruses-attached samples in a test room of approx. 25 m³, and then operate the verification device.
• Measurement of RS viruses
Collected petri dishes at each predetermined time. Used the liquid used to wash the dishes as an undiluted test solution, and serially diluted it to 10 levels. Infected cells with the undiluted test solution or diluted solution, applied the necessary treatment, and then incubated them in a CO₂ incubator for 5 days. Observed the CPE produced by the proliferation of the viruses under a microscope, and determined the virus infectivity titer (TCID₅₀/mL) using the Reed-Muench method. This test measured the infectivity titer per mL of the liquid washed out from each test piece (TCID₅₀/test piece) for determination.

[Sterilization Effects of Hypochlorous Acid: Overview of Verification Details]

Target	Verification method	Verification body	Year of verification
Influenza A virus (H3N2)	Contact with gases	Kitasato Research Center for Environmental Science	2015
Feline calicivirus (alternative to norovirus)	Contact with gases	Kitasato Research Center for Environmental Science	2015
Novel influenza virus (2009 influenza virus [H1N1])	Contact with gases	Kitasato Research Center for Environmental Science	2016
Rotavirus	Contact with gases	Kitasato Research Center for Environmental Science	2016
Methicillin-resistant Staphylococcus aureus (MRSA)	Contact with gases	Kitasato Research Center for Environmental Science	2016
Streptococcus pneumoniae	Contact with gases	Kitasato Research Center for Environmental Science	2016
Measles virus	Contact with gases	Kitasato Research Center for Environmental Science	2019
Adenovirus	Contact with gases	Kitasato Research Center for Environmental Science	2019
Enterovirus	Contact with gases	Kitasato Research Center for Environmental Science	2020
Coxsackievirus	Contact with gases	Kitasato Research Center for Environmental Science	2020
Penicillium (spore)	Contact with gases	Kitasato Research Center for Environmental Science	2020
Aspergillus niger (spore)	Contact with gases	Kitasato Research Center for Environmental Science	2020
Moraxella	Contact with gases	Kitasato Research Center for Environmental Science	2021
Micrococcus	Contact with gases	Kitasato Research Center for Environmental Science	2021
Novel coronavirus (SARS-CoV-2) Omicron variant	Contact with gases	Shokukanken, Inc.	2023
Novel coronavirus (SARS-CoV-2) Omicron variant	Contact with solutions	Shokukanken, Inc.	2023
Influenza virus (H1N1)	Contact with solutions	Shokukanken, Inc.	2023
Group A streptococcus	Contact with gases	Kitasato Research Center for Environmental Science	2024

About Panasonic Corporation

Panasonic Corporation offers products and services for a variety of living environments, ranging from homes to stores to offices and cities. There are five businesses at the core of Panasonic Corporation: Living Appliances and Solutions Company, Heating & Ventilation A/C Company, Cold Chain Solutions Company, Electric Works Company and China and Northeast Asia Company. The operating company reported consolidated net sales of 3,494.4 billion yen for the year ended March 31, 2024. Panasonic Corporation is committed to fulfilling the mission of Life Tech & Ideas: For the wellbeing of people, society and the planet, and embraces the vision of becoming the best partner of your life with human-centric technology and innovation. Learn more about Panasonic: https://www.panasonic.com/global/about.html

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