UV rays most-effective sanitising tool for zapping coronavirus

Medical care centres, virology research institutes and restaurants, globally, have depended upon ultraviolet (UV) rays as the most reliable disinfection tool for years. Previously, large, industrial-grade machines were used in decontamination processes but these have now widely been replaced with smaller versions of UV sanitising tools. These are available, within the reach of consumers, to kill germs lurking on surfaces like mobile phones and public transportation handrails.

Through precise use of self-driving UV disinfection robots to sanitise hospitals in Wuhan – the epicentre of Covid-19 – the Chinese government applied one of its most acclaimed procedures to win over the virus. These robots helped Chinese medics defeat the invisible virus during the epidemic and ensure fewer casualties.

Adrienne Murray, BBC's technology of business reporter, writes that an UV-D robot takes about 20 minutes to disinfect a hospital room where a coronavirus patient was treated.

While navigating around a room, the self-driving machine – powered with six to eight bulbs – emits concentrated and highly-effective UV-C rays. These destroy microbes and pathogens, preventing them from multiplying by damaging their DNA and RNA. Such light can successfully sanitise hard-to-clean nooks and crannies of a room. The process is complete in 10-20 minutes.

The process causes a smell of burnt hair to permeate the air. These processes are mildly hazardous to humans, so as a precaution, they must wait outside the room.

Various studies have tested and confirmed the efficacy of varied ultraviolet lights. Among them, the most effective one UV-C light has a wavelength between 200 and 400 nanometers. It is highly effective at decontamination because it destroys the molecular bonds that hold together the DNA of viruses and bacteria. It even does so for superbugs, which have developed a stronger resistance to antibiotics, writes Katie Scarlett Brandt, a freelance writer for Insider and associate editor of the Chicago Health Magazine.

Non-toxic overhead UV lighting has been found to be effective in public spaces to reduce the transmission of diseases. Removing viruses using UV light is effective because it kills germs regardless of drug resistance and without toxic chemicals. It is also effective against all germs, even newly-emerging pathogen strains.    

Use of UV light while staying home

At-home methods of UV sanitation have been proven highly effective against pathogens and come in a variety of forms — including portable wands, phone sanitizers, and toothbrush cleaners.

UV-C lights are available for consumers in various forms, including boxes, bottles, and covered wands – each has its own set of instructions for how to use the light.

Widely-used sanitising wands allow one to wave UV-C rays over anything s/he might want to disinfect, including gadgets, counters, bedding, and steering wheels. Such portable wands can be used anywhere, claim to work within seconds, and are a favourite of travelers concerned about things like hotel room sanitation. Besides objects and surfaces, UV-C light can purify water, too — when used correctly.

"We had been growing the business of UV robots at quite a high pace – but the coronavirus has kind of rocketed the demand," chief executive officer of UVD Robots ApS, Per Juul Nielsen told the BBC.

He says truckloads of robots have been shipped to China from Denmark, in particular Wuhan. Sales elsewhere in Europe and Asia are also up.

Dr Lena Ciric, an associate professor at University College London and expert on molecular biology, agrees that UV disinfection robots can help fight coronavirus.

UV light has been used for decades in water and air purification, and has been used in laboratories. However, combining them with autonomous robots is a recent development.

American firm Xenex has the LightStrike germ-zapping robot, which has to be manually put in place. It delivers high-intensity UV light from a U-shaped bulb. Recently, the company has seen a surge in orders from corona-stricken countries including: Italy, Spain, Japan, Thailand, and South Korea.

Xenex says since 2014, numerous studies have shown that it has been effective at destroying hospital-acquired infections in the clean-up after the Ebola outbreak. More than 500 healthcare facilities, mostly in the US, have the germ-zapping robots. In California and Nebraska, it has already been put to use sanitising hospital rooms where Covid-19 patients received treatment, the manufacturer says.

China's Guangdong province-based YouiBot was already making self-directed robots, and quickly adapted its technology to make a disinfection device.

An environmental sanitation consultant Paul J. Markevicius said insidious air-borne viruses usually grow unrelenting in public places with large footfalls and thus become breeding grounds for epidemics. Air-borne viruses are invisible and can be life-threatening for the young, elderly and those with weakened immune systems.

He advocates for the instant-kill, neutralizing, option proffered by UV. Ozone is a fantastic sanitizing agent in many situations and environmental applications and 3,000 times more effective than chlorine. UV is a far-better option to ensure disinfection at high visitor areas such as a shopping mall or metro escalators.

Efficacy of the Sun's UV radiation

Most of the natural ultraviolet light that people encounter comes from the mighty Sun. AccuWeather staff writer, John Roach, said researchers studied 100 different Chinese cities that had more than 40 cases of Covid-19 from January 21 to 23. Now increased sunshine could help in the Northern Hemisphere.

"The stronger Sun and increased hours of sunshine may start to take their toll on coronavirus, thereby helping to stem its spread, particularly as the sun gets stronger in April and May," said AccuWeather Founder and CEO Dr. Joel N. Myers.

The Center for Biocide Chemistries has created a list of more than 100 ready-to-use, dilutable and wipeable biocidal products that the US Environmental Protection Agency has approved as effective at killing viruses like the coronavirus. Such rampant use of chemicals is feared to be a boomerang for ecology in the near future.