Wouldn’t it be amazing if you could reuse your N95 masks dozens of times, knowing it’s completely sterilized from COVID-19 and all other germs? What if first line responders could come home and sterilize all their gear overnight? Doesn’t that sound like a fantastic way to help this critical shortage of PPE? Of course! Get the Gates Foundation on this! Call Elon Musk! Oh, wait… it already exists… it’s called ultraviolet light! More commonly called , ultraviolet light in the C-band at 254 nanometers destroys DNA and RNA just enough to stop reproduction of all germs. It’s been around for over 140 years, it’s used in many industries, and hospitals across the world already use UV-C to sterilize their rooms of all germs. It can be cheap, easy to do, and quick. It’s for medical use! So… why is no one shouting from the rooftops about this?
So, here goes my rooftop shouting. Hopefully I won’t fall off.
This post isn’t as polished as I like, but I really want this out there right now. I want people talking about this today, I want people to tell me I am crazy or not crazy, I want people to share ideas via the comments section below, I want Dr Fauci next week on TV telling people this is a great idea, I want the WHO adding this to their recommendations as standard practice to extend the life of PPE across the world.
Some Videos To Start With
Here’s a good video about UV-C, from the Mayo Clinic:
And another from CNET:
A CBS interview in 2018 about UV-C against the flu:
How Can UV-C Help Clinics and Homes Right Now?
I definitely need to do more research, and this is one reason I am writing this: I need people’s help researching more details on all of this. My main question: how good is this longstanding technology against N95 and PPE? Here’s one important study from 2015, very relevant, the title says it all: . I have highlighted major sections here:
“CONCLUSIONS: The capacity to disinfect and reuse disposable N95 respirators may be needed during a pandemic of an infectious disease that spreads by airborne particles. Ultraviolet germicidal irradiation is one possible method for accomplishing this. In our experiments, UVGI had a small effect on filtration performance and essentially no effect on flow resistance at doses up to 950 J/cm2, while the structural integrity of the respirators showed a noticeable decrease at lower doses. The strength of the respirator straps was less affected by UVGI than the strength of the body material. Our results suggest that UVGI could be used to disinfect respirators, although the maximum number of disinfection cycles will be limited by the respirator model and the UVGI dose required to inactivate the pathogen.
…the upper limit for UVGI exposure during repeated disinfection cycles would be set by the physical degradation of the respirator material and not by a loss in filtration capacity. For some respirator models, this could potentially serve as a useful warning; if the respirator material is degraded noticeably after UVGI disinfection, the respirator should be discarded…
…Two studies of UVGI disinfection of respirators exposed to droplets and aerosols containing influenza virus found that a 1.8 J/cm2 dose was sufficient to reduce the amount of viable influenza virus by a factor of >104 (>4-log reduction). This suggests that, for influenza virus, dozens of UVGI disinfection cycles could be performed on respirators without the UVGI affecting their performance….
…A working group formed by the US Department of Veterans Affairs recently proposed desirable characteristics for a disposable N95 respirator designed specifically for healthcare workers. One of their recommendations was that such a respirator be capable of being disinfected 50 times with each disinfection cycle taking less than 60 sec. Our results suggest that, with the appropriate design and choice of materials, a respirator and UVGI system could be designed to meet this goal. It would be relatively easy to design a small UVGI system that could meet the 60-sec cycle goal, while this would be extremely difficult for a chemical immersion, vapor, or steam-based system. In addition, because UVGI does not involve hazardous chemicals and can be reasonably compact and inexpensive, such systems could be deployed virtually anywhere within a healthcare facility for quick and easy disinfection of respirators by workers after tending to a patient….”
Major Safety Warnings About UVGI
- UV-C is dangerous to the eyes and skin. Definitely do not use this in
front of kids, and never ever look at the bulb or keep on skin contact. The FDA has against this: “UV light-based products could cause burns, eye damage or increase the risk of skin cancer due to over exposure.” These need to be used out of sight, like overnight on a timer; or in a small corner box. You can buy yellow filtered glasses to block the UV-C if you prefer.
- Do NOT buy UV-C lamps that brag about making ozone. Especially be careful on Amazon with LED UV-C bulbs, check the fine print, many from China emphasize ozone and this is a BAD idea as ozone is really irritating to lungs and can be really dangerous for asthmatics and people with lung troubles. Also it makes a strange smell. The FDA , “exposure to high levels of ozone gas may worsen a patients’ existing chronic respiratory diseases or increase the chance of a respiratory infection.” A good UV-C lamp has a coating that prevents the ozone. emissions at 185 nm.
My Big Questions
- What exact specs do we need to get to that VA goal of sterilizing N95 masks within 60 seconds? How much wattage; how far from the bulb; and how many seconds or minutes?
- What exact specs for a small room, let’s say 10 x 10 feet, 100 square feet? (9.3 square meters).
- Is there an efficiency difference between LED and fluorescent bulbs?
My Bottom Line
I certainly am not waiting around for Dr. Fauci, the evidence is already overwhelming. ( just 5 days ago is a good conversation starter). I have a Philips 25 watt 18″ T8 TUV lamp with fixture ($50 total) in my home’s laundry room and I sterilize my clinic objects overnight, using a timer, to protect my family. I now have a second one at work for my PPE, in a corner box.
I think in general it’s best to stick with the reputable companies like Philips, GE, Westinghouse, Sylvania etc. Philips has a and a talking about their UV-C products. Here’s the .
So, here we are at the end of my rooftop shouting. Have I piqued your interest? I certainly hope so. Talk to your clinic safety teams! Call these lighting company tech reps and get more details! Let’s work together and figure this out, this could save lives right now!
Addendum 3/31: Here are some links since this article was posted:
- Philips has great PDF on the tech aspects:
- Univ Nebraska has new UVGI site for COVID-19 and new protocol for UV-C cleaning here
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