New Material: Far UVC UV Lighting Can Easily Kill 90% Of Pathogens In The Air

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The technology represents a new "passive" way to curb the spread of covid-19, compared to existing controls that involve significant changes in people's behavior, such as adherence to blockades, keeping body distance, wearing masks or vaccinations

Compared to the challenges posed by these effective but often unpopular measures, installing far ultraviolet lighting in an indoor environment may be as easy as replacing a light bulb - and the effectiveness of the device's antimicrobial radiation is equally impressive, the scientists say.

"Far ultraviolet light quickly reduces the number of active microorganisms in indoor air to almost zero, making indoor air basically as safe as outdoor air," said biophysicist David Brenner of Columbia University Medical Center

Although the bactericidal properties of ultraviolet c-ray (UVC) are well known, the radiation can lead to sunburn, skin cancer and eye injury, which leads to strict control of its use. UVC is mainly limited to disinfection of medical equipment.

However, recent studies on shorter wavelength far UVC emitters (also known as KrCl excimer lamps) have shown that UVC spectra do not pose a safety risk to mouse or human skin cells, while retaining the ability to kill pathogens in the air.

However, the existing research is largely limited to testing far ultraviolet light in small-scale laboratory settings.

To determine whether the technology works equally well in a room of normal size, the scientists installed five far ultraviolet lamps in a controlled bioaerosol chamber of about 4 x 3 meters and pumped a stream of atomized Staphylococcus aureus bacteria into the room.

Fletcher Louise, an environmental microbiologist at the University of Leeds in the UK, said: "a single ward size enclosure in which different types of building ventilation and equipment can be implemented to test the potential effectiveness of methods such as far ultraviolet radiation in a comprehensive context."

According to the team, the far UVC lamp reduced the pathogen load by up to 98.4% in a few minutes and kept the environmental level at a 92% reduction, in line with ICNIRP guidelines.

The ventilation level of the test room was set to be the same as that of a normal room, with the same amount of air change per hour (each), but far ultraviolet radiation was equivalent to 184 air changes, which the team said exceeded any other method of disinfecting occupied indoor space

Kenneth wood, a physicist at the University of St Andrews in the United Kingdom, said: "our experiment has produced amazing results, far beyond what can be achieved by ventilation alone."

Although the technology has clear prospects, the researchers acknowledge that there are difficulties in overcoming the potential use of far ultraviolet light in the real world - especially in ensuring that the installation of far ultraviolet lamps in indoor environments meets the correct radiation exposure level, which is both effective and safe.

If the balance can be safely achieved, we may have a game changing approach to public health security, the researchers said ?

"Using this technology in places where people gather indoors can prevent the next potential epidemic." Brenner said.

"The far UVC lamp is simple to install, inexpensive, and does not require people to change their behavior, and evidence from a number of studies suggests that it may be a safe way to prevent the spread of any virus, including the covid virus and its variants, as well as influenza and any potential future pandemic virus." The results were published in the scientific report.