The emergence of the COVID-19 pandemic has significantly heightened awareness of appropriate personal hygiene and sterilisation practices. Avoiding an imperceptible threat can be profoundly anxiety-inducing for many, prompting us to seek whatever means to ensure the safety of ourselves and our loved ones. While good personal cleanliness is essential, what additional instruments and technology might be employed to sterilise and eradicate virus particles within our residences?
Ultraviolet illumination has been marketed to customers as a method for sterilisation and disinfection. Given the plethora of disinformation in recent months and the several factions unable to reach consensus, you may have scepticism towards any assertions regarding the containment of the Coronavirus. Consequently, we have compiled the material below into a concise essay to educate you on the specific types of UV LEDs suitable for germicidal, sterilisation, and disinfection applications.
Three Categories of Ultraviolet Light
Similar to visible light, UV light encompasses a broad spectrum of wavelengths. The critical specification is measured in nanometres (nm), with ultraviolet output originating from wavelengths between 100nm and 400nm. Ultraviolet light is categorised into three primary groups, which provide specificity on the kind of UV light, as its properties vary according to wavelength.
UV-A: 315-400 nm
UV-B: 280-315 nm
UV-C: 100-280 nm
The predominant ultraviolet lights encountered are often in the UV-A spectrum and are frequently designated as "blacklights." This is the least potent kind of ultraviolet light, utilised for purposes such as UV curing and blacklight painting.
UV-B possesses a shorter wavelength and is hence more potent than UV-A. Both UV-A and UV-B are found in natural sunshine; however, UV-B is the principal wavelength responsible for sunburn. Both UV-A and UV-B LEDs have significant limitations in their capacity to sterilise and eradicate viruses and bacteria.
UV-C is the segment of the spectrum to concentrate on when developing a sterilisation system utilising ultraviolet LEDs. Longer wavelengths within the 100-280nm spectrum are preferable, with those especially in the 200-280nm range sometimes designated as Germicidal UV (GUV). In contrast to UV-A and UV-B, UV-C wavelengths are obstructed or absorbed by the ozone layer and atmosphere, preventing them from reaching the Earth's surface. UV-C is the most effective light for eliminating microorganisms, although it poses significant risks to human health. In the absence of a method to use natural UV-C rays, we must seek an artificial source of UV-C light.
Mechanisms of UV-C in Virus Inactivation
For sterilisation and germicidal applications, UV-C LEDs must be utilised, as shorter wavelengths have the most significant impact on the DNA and RNA of pathogens.
DNA and RNA? It resembles a Science class, does it not?
This is a concise overview of how UV-C LEDs modify DNA and RNA, which are fundamental to life, including microorganisms and diseases (viruses, bacteria, etc.). In the absence of this genetic material, a pathogen would be incapable of reproduction, hence terminating the infectious colony.
Deoxyribonucleic Acid Helix
DNA and RNA are composed of five nucleobases in total. The initial three nucleobases present in both DNA and RNA are Cytosine (C), Guanine (G), and Adenine (A). The final two are more particular, indicating that Thymine (T) is exclusive to DNA, whereas Uracil substitutes Thymine in the RNA helix.
Studies indicate that exposure to UV-C wavelengths causes thymine and uracil molecules to absorb ultraviolet radiation and undergo a chemical transformation. This alteration destroys the cells by causing structural damage and inhibits the pathogen's reproduction. This method is most effective at around 265 nanometres. Longer wavelengths, such as those in UV-A and UV-B, exhibit inferior absorption and are hence ineffective for sterilisation purposes.
The question today is…
Do UV-C LEDs eliminate the COVID-19 coronavirus?
Laboratory testing regarding the new coronavirus (SARS-CoV-2) and UV-C LEDs is constrained; yet, previous studies on earlier viruses have prompted many to assert its efficacy. A significant challenge is that UV-C is highly absorbed by air, necessitating that UV-C sources possess sufficient power to effectively reach their target at a distance.
In April, Seoul Viosys demonstrated what they assert is the first 99.9% sterilisation of the SARS-CoV-2 virus via UV-C LEDs. The experiments were performed in collaboration with experts from a team at Korea University. The experiments demonstrated that Violed UV-C LED modules could eradicate 99.9 percent of the SARS-CoV-2 virus with an only 30-second exposure from a distance of 3 cm. Regrettably, they did not disclose the number of LEDs utilised to do this.
Shenzhen Benwei Lighting Technology Co., Ltd was established in 2010. It is a national high-tech enterprise integrating design, R&D, production and sales of indoor and outdoor lighting products and also can do OEM ,ODM .For more details about our offerings, please contact us at bwzm18@ledbenweilighting.com
