Pandemic Prevention with Light

How Using Far-UV Light Could Prevent Future Pandemics

Akshaj Darbar
6 min readMay 23, 2021
Photo by Rich Smith on Unsplash

The attempt to take control of the COVID-19 pandemic has quite clearly been an utter failure. Apart from the successful development of vaccines in a record low time, there were significant issues with detection of the virus, governmental actions to bring the virus under control, and public acceptance of social distancing, mask, and lockdown policies, as well as problems with vaccine distribution in many places even now.

As Sam Harriss and Rob Reid discuss in the episode (embedded below) on the Making Sense podcast, the fast growth of the synthetic biology significantly increases risks of engineered viruses causing future pandemics.

And, as repeatedly discussed in the podcast, it is only by random chance that the SARS-CoV-2 virus has a mortality rate of only about 3–4%. Yes, even that percent is high considering that so many lives have been claimed (3.42 million lives worldwide at the time of writing), but in the case of engineered viruses, that percent could be dangerously high. If such a virus does appear in the future, failures like the ones during this pandemic will almost guarantee worldwide chaos and destruction, as often portrayed in dystopian movies and video games.

And so, preparing ourselves to be able to quickly respond to and contain such a powerful virus is crucial. One important part of this preparation should be reducing the ability of these viruses to spread. In the current pandemic, this is achieved largely by wearing masks to prevent acquiring the virus through cough droplets in the air.

However, this has major flaws. We’ve already seen in much of the United States and other countries how opposed parts of the population are to wearing them, which means that airborne viruses can still spread quite rapidly because of such people.

Image from BBC

If we truly want to be safe from another potentially destructive pandemic, we need to be able to protect the public regardless of the actions of negligent or irresponsible individuals. Well, Dr. David Brenner from the College of Physicians & Surgeons of Columbia University may have found a solution to reduce viral spread by jaw-dropping amounts without having to rely on the full cooperation of the public. What is it? UV Light.

The Electromagnetic Spectrum

You might remember from your high school physics class that light actually behaves a lot like a wave. And just like a wave, light can also be described in terms of some basic variables. For our purposes in this article, only the frequency and the wavelength are important.

Figure from Hyperphysics
  • wavelength the length of one wave, or the distance from one crest to the next (in nanometers (nm))
  • frequency the number of cycles of the wave that pass through a single point in one second (in cycles/second, or Hertz (Hz))

It is also important to remember that as the wavelength increases, the frequency decreases, and vice versa, and the fact that a higher frequency means that the wave carries more energy than a wave with lower frequency.

What you might also have learnt is that what we informally refer to as light (i.e. what we can see) is a very small fraction of the actual electromagnetic spectrum, encompassing wavelengths of about 380 nm to 740 nm and formally referred to as visible light.

Figure from NASA Imagine the Universe!

As the frequency and wavelength of the electromagnetic waves changes, we move along the spectrum and pass through regions of different forms of light. Moving from left to right with decreasing frequency (and therefore decreasing energy and increasing wavelength), we have: gamma rays, X-rays, ultraviolet (UV) radiation, visible light, infrared radiation, microwave radiation, and radio waves.

So, with that physics primer out of the way, let’s move onto discussing UV light.

Ultraviolet Radiation

If you’ve ever forgotten to put on some sunscreen on a very sunny day (which I seem to do way too often) and spent quite some time outside, you’ve probably experienced a sunburn. Well you might already know, but that was thanks to exposure to UV radiation from the sun. Unprotected exposure to UV radiation can cause damage to the DNA of the skin, leading to mutations that could lead to skin cancer, premature aging of the skin, and damage that manifests itself as a sunburn. That’s why wearing sunscreen is important, as it absorbs UV radiation and prevents it from penetrating the skin.

Image from iStock

Just like UV radiation can damage the DNA of our skin cells and eyes, it can also damage the DNA of bacteria, viruses, and other pathogens. Because of this, using UV light has long been explored, and is also increasingly being used, as a way to sanitize. Generally, germicidal UV light has a wavelength of roughly 254 nm, but this wavelength is damaging to the skin and eyes, and so must be used sparingly in open environments where people might be exposed to it.

Dr. David Brenner, however, has found that a range of UV radiation known as far-UVC light, which makes up wavelengths of 207–222 nm, can efficiently kill off pathogens without causing damage to the skin and eyes.

Dr. Brenner specifically uses 222 nm far-UVC light, and found that a very low dose of far-UVC light could have the same sanitary effects as germicidal UV light but without any of the associated health risks.

In a scientific article he published last year, he discusses the results of his experiments with two airborne human coronaviruses: alpha HCoV-229E and beta HCoV-OC43. He found that very low doses of just 1.7 and 1.2 mJ/cm² (way of measuring the intensity of the light), respectively, could eradicate/inactivate 99.9% of all aerosolized viruses of the two forms. Furthermore, using a light of 3 mJ/cm²/hour (the regulatory limit), he estimates that 90% of the HCoV-229E virus particles could be inactivated in around 8 minutes, 95% in 11 minutes, 99% in 16 minutes, and 99.9% in 25 minutes only.

Image from National Geographic

Similar tests with aerosolized H1N1 virus (a strain of which was responsible for the extremely deadly Spanish flu) revealed that a low dose of only 2 mJ/cm² could inactivate more than 95% of the virus in the air.

Imagine if these lights could be installed, perhaps by government mandate, in public spaces. Even if people did refuse to wear masks, or wore them improperly, these lights could decrease the likelihood of contracting and spreading the virus substantially.

Now, this ability of far-UVC to be able to eradicate viruses, as well as its safety still need to be heavily tested before they can be put into public spaces. Once that’s done, manufacturing logistics also need to be figured out to be able to produce high-quality, energy-efficient, and effective lights at large scale. And then finally, installing it in all public locations is also a lengthy process.

Combined, these three steps are likely to be quite expensive, but considering that the WHO estimates a flu pandemic is likely to cost $60 billion annually, and the coronavirus pandemic alone has cost the world $11.7 trillion, investing that money would definitely be well-invested.

But investing in lights like these isn’t all we need to do. As discussed in the podcast (which I would 100% recommend everyone listens to), there are a lot of actions that need to be taken to ensure we are as prepared as possible for the next pandemic. And hopefully governments around the world have learnt a lesson from our failures in dealing with SARS-CoV-2, and become a lot more serious about investing time, energy, and money into pandemic readiness.

To stay updated with more of my articles (about different areas of technology and medicine, including lots of neuroscientific research), follow this Medium account, check out my personal website, and follow me on my LinkedIn and Twitter accounts to keep up with my progress.



Akshaj Darbar

MD Candidate at McMaster University. Researching blood cancer detection.