As the scientific community continues to grapple with COVID-19 attempting to demystify and indeed find a sure-fire treatment for it, the continual eruption of mutants and variants around the world has made the disease even more enigmatic and intractable. While vaccines of all kinds and forms developed by global as well as local pharma companies have provided some sort of a potential shield against the dreaded virus, there is no hundred percent guaranteed protection yet for people anywhere in the world. Additionally, ever since the confirmation that the virus can even be airborne and transmit through the fine aerosols in the air remaining much longer and travelling much farther than estimated earlier, the potential to infect and intensify the contagion has increased manifold. 

So, even as vaccines and other forms of treatment are being developed to eliminate the virus within the human body, the imperative to inactivate and neutralize it in the air is equally pressing. And among the limited number of technology options that have come to prominence in recent times, ultra violet (UV) light technology is one potent option. With credible research establishing now that the transmission of the Coronavirus virus occurs more in indoor spaces than outdoors, the role of ultra violet germicidal irradiation (UVGI) technology has become even more critical.

UVGI not a novel technology

Ultra violet germicidal irradiation technology has been in existence for decades now. It was way back in 1930s when scientists had experimented and demonstrated the ability of UVGI to effectively inactivate airborne microorganisms in lab settings. However, because these could not be replicated in real-life settings especially in the context of fight against measles, there was considerable hiatus before the technology was taken up with the same vigour and enthusiasm again. It was due to the rise in TB cases in the 1980s when the technology received renewed interest and attention. 

UV-C the possible antidote to SARS-CoV-2 virus

First and foremost, not all ultraviolet can be taken as being germicidal. Unlike the longer wavelength UVA and UVB which lie in the spectral band of 320-400 nm and 280-320 nm respectively, it is only the short wavelength in the spectral band of 100 to 280 nano metres which is most effective for disinfection. However, longer, less energetic UV can also disinfect if applied in much greater doses. At the same time, far UVC light in the spectral range of (207 to 222 nm) has also been reported to be as efficient as conventional germicidal UV light in eliminating microorganisms, but without causing adverse health fallout for humans as is the case for the latter.

The usage of UVGI technology so far: versatility a virtue

For quite some time now, UVGI has been widely used in healthcare settings, hospitals and water treatment plants etc with utmost precautions. Even some of the popular forms of usage  such as low pressure mercury lamps, far-UVC or eximer lamps, pulsed xenon lamps and LEDs – entail risks to human health and are used with adequate safety precautions. Poor installation of UVC lamps have been reported to cause skin and eye burns in people. Typically, hospitals and treatment facilities use UVGI technology in the form of upper-room fixtures, mobile units and HVAC systems, thereby testifying to the versatility of this technology. That it can be also fitted with both in-duct and on-coil HVAC systems further reinforces this versatility. Until now, upper-room UVGI has been considered the safest and most effective application of UV-C.

UVGI apt for smaller indoor spaces

However for smaller indoor spaces with less height, which are typically characteristic of personal and domestic home spaces, upper air fixtures are not implementable. Therefore, in these smaller private spaces, UVGI fitted in HVAC systems, including air handling units (AHUs), FCUs, Cassette ACs and now even Split ACs, would be more suitable. This is especially critical in light of the higher prevalence of corona virus in indoor spaces than outdoors. At the same time, it must be worthwhile to note that embedding UVGI technology in an HVAC system in smaller spaces would require sufficient and timely ventilation, repeated air filtration and constant air quality monitoring. In an estimate, disinfection of air would require much higher rates of ventilation at between 6 and 12 air changes per hour (ACH).  Nonetheless, when combined with electronically charged filteration (ECF) and Filterless Magnetic Air Purification (FMAP) technologies, an air purification system complete with UVGI technology can turn out to be a ‘wonder cure’ of sorts for airborne infections including the deadly corona virus infection. So, although UVGI itself is not new, an innovative application of this technology in tandem with other emerging technologies can go a long way in addressing COVID as well as other infection issues.   

What determines the effectiveness of UVGI technology?

While wavelength as a principal parameter has been explained earlier, it is the amount or dose of ultraviolet energy impacting a surface per unit area that determines the effectiveness of this technology. At a certain wavelength, the UV power, the duration of exposure and the distance between the UV emitter and target surface, which could be aerial in form, define the effectiveness of UVGI technology.

The emerging endemicity of COVID-19

The recent assessment by a section of experts terming the pandemic as one ‘mutating’ into a sort of an endemic in the country owing to low transmission levels and a large population already exposed to the virus further strengthens the case for employment of UVGI technology integrated with HVAC installations, which does not only provide protection against coronavirus but all similar viruses and harmful pathogens that stay suspended in the air we breathe. Today there are high efficiency UVGI solutions that can be integrated with even Split and Cassette ACs, providing air sanitization not just in larger public spaces like offices, hospitals, shopping malls and hotels, but also in smaller indoor spaces salons, gyms, clinics, showrooms or restaurants. UVGI solutions are also extremely cost-effective, which makes it even more relevant for large-scale adoption. There are plenty of UVGI solution providers in the market today, but as a mark of quality, consumers can look for Indian and global certifications like UL, CSIR, CE etc. Countries around the world are installing UVGI solutions at mass scale in public areas to provide protection against coronavirus. Air sanitization is not a luxury anymore but a necessity, with COVID-19 having been declared as an endemic as it is expected to impact our lives for a long time to come.