VIDEO: Professor explains UV-C technology
February 14, 2021
Recently, the concern has been about airborne or aerosol transmission of disease—most notably SARS-CoV-2, the infectious agent that causes COVID-19.
When we have respiratory infections, we expel infectious particles. And if these particles, or little droplets, are small enough, they won’t settle out very quickly, and they’ll actually remain airborne. We can inhale them, and that’s a possible route to infection. Because in order for us to get infected, we have to inhale a high enough concentration of those infectious particles.
Outdoors, there’s a lot of air. And air is constantly moving at pretty quick speeds. Indoor spaces—there is a smaller volume of air. And being indoors, in close proximity to an infected person, comes with some risk of airborne infection.
How can you clean indoor air of pathogens?
You can have a traditional air filter, which just collects particles. You can have other technology, including ultraviolet irradiation, and that’s designed not to collect particles, but to actually inactivate—or kill, if you will—infectious agents.
All UV light is certainly not the same, in the same way that visible light has different colors. UV has ranges A, B and C. And in terms of pathogen inactivation, UV-C in particular has wavelengths which can be absorbed by the genetic material for bacteria and viruses.
When absorbed, they cause a reaction that kills bacteria or inactivates viruses. Coronaviruses in particular look like a type of virus that is very susceptible to UV irradiation.
What should I consider to help clean the air in a home or office?
If you are working in an indoor space where you’re concerned about risk of infection and you’re thinking about getting a recirculating air purification unit, you want to make sure it incorporates technology that efficiently removes the particles you’re concerned about.
HEPA filters are designed to collect particles as efficiently as we possibly can. The next question to ask is: Well, are they still active on that surface? How long do I have to wait?
But when you inactivate, that’s really it. It’s done there. I think that’s a huge advantage in inactivating technology, or UV.
What are the best applications for a portable UV-C unit?
These instruments can be rather compact if designed well, and they can be incorporated into a variety of environments. Home, office spaces, dental offices or medical offices can utilize recirculating air purification technology, and [they’re] usually pretty portable.
The flow rate in the device needs to be high enough that it effectively increases the ventilation rate in that space. If it’s little, it’s going to have a local effect only, so you’d want to keep it close yourself.
If my goal is to reduce risk of infection, well-designed UV technologies can get the job done.