From left to right: Dr. Udy Bar Josef, head of scientific operations at Sterlights, posing with Tom Fard, owner of K-Market Esplanadi, and Yiftach Atzmon, co-founder of Sterlights. Photograph: Sterlights

As the coronavirus pandemic proceeds into its second year and most of the world is still in the grip of lockdowns, social distancing, face masks, and relentless scrubbing of surfaces with disinfectants, recent technological advances in the field of UV light may yet offer a better way to deal with our new reality.

Among those trying to apply UV light technology to mitigating the ongoing pandemic is a Helsinki-based start-up called Sterlights. Established in July of 2020, the company champions the use of so-called far-UVC light as a method of disinfection for air, surfaces, spaces, objects, and so on—and provides various solutions using that technology, tailored to the needs of various businesses and organizations.

When observing the global response to the coronavirus pandemic, Sterlights’ co-founder Yiftach Atzmon was particularly perplexed by the lack of green solutions to sterilizing social spaces and personal objects. He believed there must be, firstly, a more efficient way of disinfection than the most widely implemented one of using chemicals, a continuous method that would not require constant re-application; and secondly, an environmentally friendly one. When his research led him to far-UVC light, he teamed up with biologist Dr. Udy Bar Josef, who went from academia (University of Tampere) to become head of scientific operations at Sterlights, and the company began its journey of offering new solutions for the current global crisis.


“Today more than ever,” Atzmon says, “we understand we need safe and sterile environments.”

Yiftach Atzmon, co-founder of Sterlights


What is far-UVC?

Ultraviolet (UV) light is invisible to the human eye and has a wavelength on a spectrum of 100-400nm. It is grouped into three categories: A, B and C. Of the three, UVC light, which has a spectrum of 200–300nm, has germicidal properties, meaning that it penetrates the cell walls of essentially all pathogens and disrupts their DNA, making them inactive and non-contagious. That is why the ozone layer surrounding Earth absorbs UVC coming from the sun, while the other two are shielded against with mere sunscreen. If UVC reached the surface, life as we know it would not exist.

As a method of killing germs, however, UVC has long been recognized for its efficiency, since it can eliminate 99,9% of all pathogens within minutes of exposure. Decades ago, scientists discovered the optimal wavelength for this germicidal effect is at 254nm, which is the wavelength most UVC lamps emit. However, this spectrum happens to be harmful to human eyes and skin due to its ability to penetrate cell walls and disrupt DNA material, which is why UVC has had limited utility until now.

However, recent research, which began in 2005, has shown that UV light on the spectrum of 210–240nm does not harm human skin or eyes, yet nonetheless has “at least the same, if not greater, germicidal efficacy than the 254nm wavelength,” explains Dr. Bar Josef. Experiments determined the optimal wavelength to be at 222nm, and the new category was finally dubbed “far-UVC.” Using the wavelength at the radiation standards prescribed by the EU or by American regulators, far-UVC would reduce the viral load by 50–80% of all airborne pathogens in any treated space. This includes not only the coronavirus, but all other viruses and bacteria, even those that are yet to arrive. “I believe far-UVC can be a real game-changer here,” Dr. Bar Josef concludes.

The onset of the coronavirus pandemic has certainly increased demand for the kinds of solutions 222nm far-UVC light can offer, and manufacturers have been scrambling to bring products based on it to market, Sterlights being the first to introduce the technology in Finland. As Atzmon points out, the great thing about far-UVC is that it offers “a continuous disinfection method in any surrounding with no environmental cost or danger to human health and safety,” which is why the company can offer products to all sorts of organizations, from hospitals to restaurants, offices, schools, sporting and cultural venues, as well as to the individual consumer. “Today more than ever,” Atzmon says, “we understand we need safe and sterile environments.”


How to use far-UVC?

Far-UVC can be used to disinfect air, surfaces, spaces, personal objects, and more, and Sterlights offers a variety of products to fit this variety of applications from the world’s leading far-UVC manufacturers. These products include gates with far-UVC light that can be used in entrances to social spaces like airports or shopping malls, wall or ceiling lamps that can be installed in occupied rooms, as well as disinfection boxes for our personal items.

With the wide array of products available, Atzmon suggests a holistic approach, where a client might consider using three to four different solutions simultaneously to maximize disinfection efforts.

According to Atzmon, many organizations around the globe have already adopted far-UVC solutions in one form or another, citing examples from airplane manufacturer Boeing to the Tokyo Metro and the Miami Dolphins from the NFL and the Miami Heat from the NBA. In Finland, Sterlights has already done several installations, such as in restaurants and hair salons in the Helsinki area, a dental clinic, and Eläinklinikka Saari in Vaasa, as well as working with the Vaasa health department.

I believe far-UVC can be a real game changer here.

Dr. Udy Bar Josef

Earlier this week, the lamps were installed in K-Market Esplanadi and K-Market Erottaja in Helsinki, assuring that any customer next to the cashier is safe in a sterile, coronavirus-free environment. “The safety of K-Market customers is highly important for us, therefore I am committed to provide the best solution to create a Covid-free store. Customers are appreciating this effort and are keen to learn more about the far-UVC technology and interested in other locations where it was installed, ” says Tom Fard, the owner of both K-markets at Esplanadi and Erottaja.

Notably, they have also helped private healthcare provider Terveystalo launch a campaign about the importance of disinfecting our mobile phones and other personal devices by installing UVC disinfection stations for phones around Helsinki. It was the first campaign in Europe to promote the use of UVC for everyone, allowing every person to engage with this technology.

Our mobile devices are the most contaminated objects we have. It has been established that the coronavirus can stay on the surface of our phone for up to four weeks, which means even frequent hand washing and use of alcohol disinfectant may not be much help if we then keep touching our phone. Instead, Atzmon insists, “disinfecting our personal devices should become part of the hygiene protocol for any organization or business,” and UVC light offers the most effective way of doing that.

For precisely this purpose, Sterlights offers a UVC disinfection box for personal devices called Cubby+, which was developed by American manufacturer Vioguard and is currently the only UVC-based product with FDA approval as a medical device. 

Sterlights working on a disinfection campaign at health care provider Terveystalo. Photograph: Sterlights

A far-UVC day

On Monday, February 22, which is symbolic of the 222nm wavelength of far-UVC light, manufacturers and researchers around the world will come together to promote and raise awareness about the benefits of this new technology and urging for it to be implemented in the fight against the ongoing pandemic.

Sterlights will help these efforts in Finland, and the Nordics and Baltics more broadly, hoping eventually to expand to the whole of the EU. They aim to promote and distribute far-UVC solutions to clients across the EU, but also to develop their in-house medical products based on far-UVC technology. To this end, they are already in negotiations with the Israeli government and hospitals there to start clinical trials, as well as collaborating with VTT in acquiring validation for new medical technology in Finland.

“Coronavirus survival as function of the dose of far-UVC light. Fractional survival, PFUUV / PFUcontrols, is plotted as a function of the 222-nm far-UVC dose. The results are reported as the estimate plaque forming units (PFU)/ml using the conversion PFU/ml = 0.7 TCID50 29 by applying the Poisson distribution. Values are reported as mean ± SEM from multiple experiments (n = 3 alpha HCoV-229E and n = 4 for beta HCoV-OC43); the lines represent the best-fit regressions to equation” Illustration: Manuela Buonanno et al., Nature, 2020


Atzmon summarizes that far-UVC is safe, efficient and environmentally friendly. Based on the latest research, both Atzmon and Dr. Bar Josef are convinced that far-UVC is the best way for us to return to the kind of life we had before the pandemic. “Our target is to help businesses, hospitals, schools, etc., to get back to their normal routine,” says Atzmon.

Dr. Bar Josef points out that vaccines, now widely seen as our best bet in returning to normality, may not be efficient against all possible strains of the virus, nor is it certain for how long they will offer active protection against the virus, which means it might be necessary to keep developing new vaccines, at significant cost. More significantly, the current vaccines will not protect us from other viruses and pandemics yet to come. Far-UVC light, on the other hand, is a proactive shield that eliminates all sorts of pathogens. It is an easier and relatively cheap method to use and with the potential to reduce the infection rate worldwide, in some calculations, more than 50%. Atzmon and Dr. Bar Josef stress, however, that far-UVC technology is not meant as an alternative to vaccines or masks, but rather a complement—a crucial one in their view.

Far-UVC can “reduce and mitigate the current pandemic and prevent the next one,” assures Dr. Bar Josef, and Atzmon adds that it can also enable us to not be afraid of the next pandemic, knowing we have the resources to combat it. While measures like face masks, social distancing, and vaccines are ways to protect from the virus, using far-UVC light would be an effective way to attack the virus. But Atzmon urges us to act fast, keeping in mind the potentially dangerous side effects our handling of the pandemic may have, from anxiety, depression, stress, not to mention the coming financial crisis.

However, Atzmon and Dr. Bar Josef from Sterlights believe they have found an ultraviolet lining, so to speak, in the crisis we face. While the human eye may not be able to see it, there is nonetheless a light at the end of the tunnel.

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