Enlisting UV-C in the Fight Against Disease

UV-C ultraviolet radiation has been proven to be highly effective against bacteria and viruses for well over a century.

It was 1877, when British physiologist Arthur Downes and scientist Thomas Blunt noticed that when putting solution-filled test tubes outside that sunlight could kill or inhibit the development of pathogenic bacteria. Some 25 years later, the German ophthalmologist Ernst Hertel built on this knowledge, determining that light in the UV-C wavelength, rather than UV-A or UV-B, is the most effective for killing micro-organisms. This is the basis of all modern commercial UV-C solutions.
But there is a catch; when used incorrectly UV-C or GUV (germicidal ultraviolet radiation) can be incredibly dangerous. That said, according to the US Illuminating Engineering Society’s Photobiological Safety Committee, the dangers of GUV are, “manageable and minor compared to potential infection prevention.”

Although it has been used and relied on for decades, the general public are generally unaware of the GUV’s unique abilities as a broad-spectrum disinfectant. It was first used in the late 1800’s to sterilise surfaces, then water in 1910 and air in the 1930’s. The application and technologies are so well developed that UV-C/GUV is a standard component of the World Health Organisation’s tool kit in dealing with Tuberculosis and many other bacteriological/viral pathogens. In fact, UV-C is generally effective against all known pathogens, the dosage being the variable. From Tuberculosis to Ebola and now Covid19, UV-C has been a key weapon in increasing safety in environments.With the technology proven effective and coupled with recent interest due to Covid-19, opportunities in healthcare, hospitality, gyms, childcare, and aged care are growing exponentially.

Before we get into some of the specific solutions available, let us get back to basics. What is UV-C/GUV, and how does it work as a disinfectant? GUV refers to the use of UV-C, the wavelengths in the photobiological UV spectral band ranging from 200 to 280nm (nanometres). Unlike UV-A and UV-B, UV-C can be up to 99.99 percent effective when it comes to breaking apart DNA/RNA, rendering bacteria, viruses, fungi, mould, and spores inert, therefore harmless. This is because Earth’s upper atmosphere blocks most, if not all, of the UV-C coming from the sun. Due to this, pathogens have evolved few if any defences to UV-C/GUV.

With most infections either entering the body directly or indirectly via the eyes, nose or mouth it is no surprise that UV-C is being employed to disinfect both surfaces and airspaces.
There is a lot of misleading information, and even some unscrupulous companies, pushing false claims around UV-C. No matter the product or claim two universal truths about UV-C are always true:

1. UV-C exposure to humans is damaging and exposure needs to be eliminated or carefully controlled.
2. The final level of disinfection is always a combination of time and intensity that varies depending on pathogen and environment.

It is for these two reasons that proven, certified products and solutions must be the priority when implementing any UV-C/GUV solution.
There are a few reputable companies specialising in UV-C applications, many in very specialist areas such as Air Conditioning and Water Treatment. They typically provide a design service that treats each application as a project with pre-implementation and post validation tests to guarantee safety and efficacy.

One such company is Signify (formerly Philips Lighting), who have been designing and manufacturing UV-C solutions for over 40 years. Recently Signify engaged the National Emerging Infectious Diseases Laboratories at Boston University in the US to specifically validate the effectiveness of their UV-C light sources against SARS-CoV2 and COVID-19. If you need any further information, please reach out to your local wholesaler or Philips Account Manager.