Short’ish answer - It’s complicated and maybe expensive, but perhaps. Can we harness the power of UV to kill viruses and other pathogens without harming ourselves?
Unfiltered sunlight, contains a full spectrum of electromagnetic radiation frequencies, spanning dangerous high-powered rays, Ultraviolet or UV, the visible light spectrum, warming infrared and low-power radio waves. Luckily for us, the ozone in our atmosphere reflects or filters out the really harmful high-frequency radiation, or we’d all be crispy critters, but some UV, visible, and radio waves do come through.
The UV radiation is made up of UV-A (less powerful; gives us wrinkles) UV-B (more powerful; if we’re exposed for long time gives us sunburns and skin cancer) and UV-C (most powerful, sunburn in seconds, will fry you.) Luckily, UV-C is filtered out by the ozone layer, so we are not affected by it when we are outside in the sun. To better understand how to harness the power of UV, let’s examine how UV radiation causes damage.
UV radiation creates gluey fusions or crosslinks in genetic material (DNA or RNA). If you think of a DNA strand like a zipper, a UV-induced crosslink will cause the unzipping machinery to get stuck at the fused part, messing up replication. The more powerful the UV, the more crosslinks, and therefore more damage, potentially lethal to something with a small genome, like a virus. It does take longer to damage something bigger and more complicated like a human genome, but UV damage can build up over time.
Now it gets tricky: can we find a UV wavelength that will kill viruses, but not humans? And if so, can we build emitters to continuously sterilize public places like airports and hospitals? Turns out UV-A (315-400 nm) is too feeble, UV-B (280-315 nm) too dangerous and UV-C (100-280 nm) even more so. BUT far-UV-C (207-222nm) might do the trick. (A nerdy aside, a nm = nanometer, or a billionth of a meter. 1 meter = 1,000,000,000 nanometers. Mindbogglingly small.)
An article in the June 2020 journal Nature studied far-UV-C sensitivity on previously identified coronaviruses and influenza viruses. Exposure to far-UV-C disables the D/RNA of very small things, like a virus, but does not penetrate the first few layers of dead skin cells on our body, or the layer of tears protecting our eyes. The information generated by the experiment has been extrapolated to the similarly-structured Covid19 (size of the virus, length of genetic material, spike proteins). According to the article, continuous low-dose far-UVC light emitters could result in over 99% of eradication of virus in 25 minutes.
This could be a game changer for use in high traffic and danger areas like airports and hospitals. More research on the subject asap please!! But where does that leaves us regular folks without far UV-C emitters? I guess we wait until product testing and subsequent manufacture allows such technology to be publicly and affordably available. Heading outside and hoping sunlight will work will not be enough.
Sunlight containing the regular UV spectrum will increase your vitamin D levels which are immune supportive, and being in the light will boost your mood. But until we verify the efficacy of far-UVC and then build enough units to make a difference, we are back to the advice of: wear a mask to contain your exhalations and protect you from other’s, wash your hands, don’t touch your face, maintain healthy spacing and cooperate with quarantine directives. We’ll get through this, but only if we all do it together.
