UV-C Lamps Can Kill Coronavirus. Shout This From The Rooftops!

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….

UV-C lamp sterilizer at home
UV-C lamp sterilizer at home

…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
    LED UV-C bulb
    LED UV-C bulb

    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

  1. 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?
  2. What exact specs for a small room, let’s say 10 x 10 feet, 100 square feet? (9.3 square meters).
  3. 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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17 thoughts on “UV-C Lamps Can Kill Coronavirus. Shout This From The Rooftops!”

  1. Steam is mentioned above, as being incompatible with the
    60 second goal, This suggests it MIGHT be an alternative candidate if the 60 second goal wasn’t important to you. (It isn’t to me as an individual for private use)

    I’d assume, though, that conventional autoclaving might be required, which would probably also degrade the material.

    I’d be concerned about particles within a depth filtration medium being shielded by it, though perhaps the studies address this possibility,

    Here in Tawan one can buy masks made of thin foam sheet which apparently resist boiling water. They probably don’t perform very well, but I use them asan inner filter to protect another non-reusable (? AFAIK) mask from my saliva and sweat, extending its life.

    1. I have not heard any doctors talking about steam, I agree it sounds unwieldy. We have a ton of evidence already for UV-C, it’s cheap, anyone can buy even on Amazon, plug in and that’s done.

      1. But you are comparing apples to oranges with studies that use already approved FDA devices? I’d rather use dry vapor steam as mentioned before, which qualifies as a FDA disinfectant-on home surfaces at least. Virus contaminated masks which could include other contaminants from touching those masks after touching surfaces is alternate fomite transmission ‘vector’ if you will. ie, dirty transmission could impart block/impair that UVC sterilization efficacy. I’d have to read those peer reviewed dbl blind randomized trails very closely for details b4 I’ll agree with this method you propose. post them all up as references please.

        Cheap UV bulbs are not the same as hospital grade UVC machines. I dont have access to an easily viewable full txt version of this study on the Ladybug system TANC reported on that is also fast for surfaces that UVC might not be as good on whereas steam penetrates where light can’t go, no study on correct application for masks or other PPE not designed for high heat exposures, however 🙂 :

        ^click on the side links from that one, for more studies on disinfection/sterilization < IR light also works fast, but the devil is in the details for correct application procedures & proper equipment. This is not as simple as McGyvering a UVC sterilization device.

        Can’t seem to find any data on viral biofilms, only bacterial, a few viruses that can penetrate bacteria for that kind of biofilm production/protection from various disinfection methods, but nothing on the pandemic viruses.

        Also haven’t seen much in the way(don’t have the time to search) of the very common 2ndary bacteria pneumonia that are the big killers for influenza, with Covid-19. It appears to be unresolved by the experts, the incidence of/levels or causation factors of cytokine storms being seen in Covid-19 patients. Few wks ago(can’t find a transcript) on a Foxnews interview, Dr. Amesh Adalja, a senior scholar at Johns Hopkins, mentioned little evidence of 2ndary bacterial pneumonia infection with Covid-19…could be just not enough data points yet, implying only viral pneumonia response as cause of deaths.

        If you haven’t seen it, a great 30min overview with extensive 3D graphical representation on the science of SARS-Cov-2(as of early Mar) done by the billionaire MD that now owns the LATimes.

      2. There’s more and more UVGI data coming out by the day, already a Facebook private group talking about how best to use UVGI. Also started at U Wisconsin, exactly as I was hoping: Also I disagree that “cheap light bulbs are not the same as hospital grade UVC machines”, that’s just not true, a proper UV-C dose is the same no matter what lamp, Philips makes lights of all sizes, the data is clear, the timing of course would be longer, but for example my Philips bulb was $20 and has high output at 50W, you can read all the tech specs in their PDF here

        says:

        Blogged it:

      3. How quickly would the virus be inactivated by the 100C water-soak I’m using? I’d think it’d be PDQ, but anyway I’m not in a hurry.

        For masks that can’t be wetted and.or heated (I’m unclear how general this is in practice) how about a dip in 70% ethanol? It dries pretty quickly and is recommended for treatment of surfaces.

        Some UVCaveats, some of which echo your unanswered questions above

        1. Heat at 56°C kills the SARS coronavirus at around 10000 units per 15 min (quick reduction).
          This and other ways to kill the virus are listed at
          “First data on stability and resistance of SARS coronavirus compiled by members of WHO laboratory network”

          1. The above data is for the SARS-1 virus. There is a new article in Lancet about the SARS-CoV-2 stability that states “With the incubation temperature increased to 70°C, the time for virus inactivation was reduced to 5 mins.” So it looks like if you heat up the mask to 168 degrees Fahrenheit for 5 or 10 minutes it should kill the SARS-CoV-2 from the mask. The paper says that SARS-CoV-2 can survive on facemasks for 7 days, so sterilization is necessary.

      4. Just a point of clarification.
        Not all UVC light increases your risk cancer and cataracts although UVC at 254 nm wavelength from mercury lamps does do this.
        In order to do damage to DNA, the UV has to reach the cell nucleus.
        As it turns out, far UVC at wavelengths of 222 nm is absorbed by surface non-living skin or eye layers and does not penetrate deep enough to cause damage. This is shown in studies comparing the two wavelengths in mhttp://gangta62.icu/illness/coronavirus-covid-19/uv-c-lamps-can-kill-covid-19/ice ( see 1,2,3, below ) and in a study of long term exposure of 222 nm UVC to UV susceptible mice. 10.1111/php.13269

        The general idea of this is reviewed in the 2017 Ted Talk “A new weapon in the fight against superbugs” given by David Brenner who heads
        The Center for Radiologic Research at Columbia University Medical
        Center

        Devices currently sold by sterilray.com/ and used in hospitals employ a patented 222-Nanometer Krypton-Chlorine Excimer Lamp to clean HVAC equipment and rooms.
        However, their use in occupied areas is still awaiting FDA approval.

        The devices that Sterilray sells currently are expensive because they are hand made by hand but prices could go down if production was scaled up.

        There are studies showing 222 nm UVC is effective against aerosolized virus ( 4) , surface microorganisms (5) and surgical sites (5) . The Sterilray company has a study on disinfecting skin .
        Sterilray also has studies showing results from disinfecting skin, conveyor belts and foods, etc:

        These devices would seem to be very valuable in the fight against Covid-19 since they have been shown to be effective against aerosolized virus ( 4) and surface microorganisms (5).

        I am trying to find out why far UV has not been approved by the FDA.
        It may be guilt by association since it is a common belief that all UV causes cancer and cataracts. Or it may be neglect of things that help fight pandemics.
        The studies in mice and limited studies in humans seem very good. Please spread the word.

        1) Germicidal Efficacy and Mammalian Skin Safety of 222-nm UV Light. [Buonanno, et al , Radiat Res. 2017] Radiat Res. 2017 Apr; 187(4): 483–491 ,
        2) “Chronic irradiation with 222-nm UVC light induces neither DNA damage nor epidermal lesions in mouse skin, even at high doses” , Narita, Kouji, et al 10.1371/journal.pone.0201259 ,
        3) “Evaluation of acute corneal damage induced by 222-nm and 254-nm ultravioet light in Sprague-Dawley rats” , Kaidzu et all Free Radic Res. 2019 )
        4) Far-UVC light: a new tool to control the spread of airborn-mediated microbial diseases, Welch, et al, RePoRts (2018)
        5) Disinfection and healing effects of 222-nm UVC light on methicillin-resistant Staphylococcus aureus infection in mouse wounds. J Photochem Photobiol B. 2018 Jan;178:10-18. doi: 10.1016/j.jphotobiol.2017.10.030. Epub 2017 Oct 27.

        1. Thanks for this. I actually emailed the far UV team at Columbia where the research is done, they’ve been having struggles getting final approval of far UV, but in theory it would be great. In the meantime, CDC just approved UV-C to clean PPE and masks so let’s get this going.

      5. So I spent last week investigating UV-C and broadband UV light sources for a cleansing application at the entry and exit of hospitals to assist health workers. I contacted the manufacturers of the better quality UV-c “xenon pulse” light sources in clinics. Before proceeding with a product development I dug into the testing that has been done on this technology for any viruses and bacteria. The tests I found focused on “improvements” not the kind of 99.x percent elimination I was hoping for. I therefore think once again that this provides some help but is definitely something that needs a lot more study and currently I was unable to find any lab that had resources to study this. One of the manufacturers told me FDA does not approve this type of a solution as a cleansing solution as it is not actually a ‘medical device’.

        1. If you are talking about UV-C light that beams on people, that’s definitely not approved by the FDA. You are talking about far UV-C which has interesting data but isn’t approved. Regular UV-C has decades of FDA approvals but of course cannot be used with people there.

          says:

          if the main material of mask is Polypropylene melt-blown, is important to know that Polypropylene is liable to chain degradation when exposure to UV

          says:

          Great thoughts here! It’s an important question whether UV light disinfection harms masks. Fortunately researchers have tested this already, and the answer is “not much.” I summarized the results of that study here:

          Be well!

          1. Thanks Thomas! Your Smartair team as usual did a great job with their new article.

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