Panasonic is the First in the Industry^1 to Verify That Gaseous Hypochlorous Acid Inactivates Over 98.5% of Influenza Viruses in Respiratory Droplets^2

Air Conditioning

Osaka, Japan – Panasonic Corporation (https://holdings.panasonic/global/) announced that its Heating & Ventilation A/C Company (hereinafter referred to as Panasonic) is the first in the industry*¹ to confirm that gaseous hypochlorous acid inactivates over 98.5% of influenza viruses in respiratory droplets under conditions simulating actual use*². This result is at the research stage. The technology has not yet been put into practical use, and the performance described here is not guaranteed in any products currently available on the market.

In recent years, outbreaks of various infectious diseases—such as influenza, COVID-19, and mycoplasma pneumonia—have been reported. There are three main routes of transmission—airborne transmission*³, contact transmission*³, and droplet transmission*³. During the COVID-19 pandemic, “social distancing” which means keeping a distance more than two meters between people became widely promoted and a major topic of discussion as a measure against droplet transmission.

For approximately forty years*⁴, Panasonic has been researching hypochlorous acid technology and has 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 has expanded its focus from merely “suppressing causative agents of diseases” to “suppressing the diseases themselves.” Panasonic is the first in the industry*⁵, to verify the disinfecting effects of hypochlorous acid on airborne and surface-adhered bacteria in real-use environments.

Panasonic has evaluated effectiveness of hypochlorous acid against airborne and surface-adhered bacteria and viruses under assumptions of airborne and contact transmission. This time, however, it conducted its first verification simulating droplet transmission, using the influenza viruses. With completing two essential preparatory steps for this verification—confirming that gaseous hypochlorous acid can inactivate influenza viruses encapsulated in water within seconds*⁶, and establishing a technique capable of capturing a sufficient amount of droplets to evaluate the effectiveness under simulated coughing*⁷—the company has exposed droplets containing influenza viruses, generated from a simulated-cough device, to gaseous hypochlorous acid and collected them at a distance of 2 meters from the device.

Panasonic is the first in the industry*¹ to confirm that gaseous hypochlorous acid inactivates more than 98.5% of influenza viruses contained in respiratory droplets*² under conditions simulating actual use. Based on the results, it is presumed that maintaining a certain concentration of hypochlorous acid in the air, gaseous hypochlorous acid rapidly dissolves into the moisture of droplets. As the moisture evaporates, the hypochlorous acid becomes more concentrated, enhancing its virus-inactivating effect.
Professor Yoshihiro Sakoda of Hokkaido University, who served as an advisor for this verification, stated, “The H1N1 influenza viruses evaluated in this study exhibits properties and susceptibility to disinfectants comparable to those of the seasonal H3N2 subtype (subclade K) circulating this year. These findings therefore suggest applicability not only to H3N2 but also to other influenza viruses. I hope to see further verification involving additional viruses and bacteria.”

*1: Regarding the verification of virus inactivation within airborne respiratory droplets under conditions simulating actual use—conducted using a simulated cough generator and an opposing collection device. In Japan's air purification and air conditioning industry. As of January 15, 2026, according to Panasonic's research.

*2: The value represents the average of three inactivation tests conducted under the following conditions: an ambient temperature of approximately 23°C, a relative humidity of approximately 50% RH, a distance of 2 meters between the electrostatic collection device and the simulated cough generator, and a gaseous hypochlorous acid concentration of approximately 10 ppb.

*3: Reference: https://www.caicm.go.jp/knowledge/index.html

*4: Including SANYO Electric Co., Ltd.

*5: Panasonic is the first in the industry*¹ to verify the inhibition of airborne and adhered bacteria in a real-world space by using hypochlorous acid: https://news.panasonic.com/global/press/en250116-2

*6: Narihata, K. et al., Rapid inactivation of aerosolised influenza virus using low-concentration gaseous hypochlorous acid. Scientific Reports 15, 33610 (2025). https://www.nature.com/articles/s41598-025-19020-8

*7: Narihata, K. et al., (in press) Development and evaluation of electrostatic aerosol-to-hydrosol sampler for single-pass airborne influenza virus sampling, Aerosol Science and Technology (2026). https://www.tandfonline.com/doi/full/10.1080/02786826.2025.2609926

[Details of Verification]

Figure 1.

Verification organization: Panasonic Corporation
Verification equipment: electrostatic collection device (developed in-house)*⁷, simulated cough generator*⁸ (Figure 1)
Verification environment: approx. 25 m³ room (equivalent to approx. 6 tatami mats), no ventilation, temperature approx. 23°C, relative humidity approx. 50% RH
Target virus: Influenza virus A/Puerto Rico/1968 (H1N1)
Verification method:

- With collection liquid (a medium to capture virus particles) placed inside the collection tube of the electrostatic collection device, the test space was set to still air, and the device was operated for 1 minute.

- A container holding virus-containing liquid was connected to the simulated cough generator, which dispersed simulated coughs three times at 5-second intervals. One minute after the first spray, the electrostatic collection device was stopped.

- After collecting, the collection liquid inside the tube was retrieved and used as the stock sample to prepare 10-fold serial dilutions.

- Viruses in the stock sample or diluted samples were adsorbed onto MDCK cells, processed, and incubated in a CO₂ incubator for 72 hours.

- Cytopathic effects (CPE) caused by viral replication were observed under a microscope, and the viral infectivity titer (TCID₅₀/mL) was calculated using the Reed–Muench method.

- The virus inactivation rate was determined by comparing results obtained in an environment with no gaseous hypochlorous acid present and results obtained in an environment containing approximately 10 ppb of gaseous hypochlorous acid.

Verification Results: Viruses contained in respiratory droplets generated by the simulated cough device were inactivated by over 98.5% during their transit into the electrostatic collection device, due to exposure to gaseous hypochlorous acid. (average of n=3).

*As a reference, additional tests were conducted at distances of 1.5 m and 1 m (both n=1), resulting in inactivation rates of 92.9% and 64.1%, respectively.

(a) Schematic diagram of the verification apparatus.

(b) Simulated cough being discharged (photographed from the side of the apparatus using water without virus).

What is Hypochlorous Acid?

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.

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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