Safety concerns around far-UVC radiation
Poking holes in the premises of the claim "far-UVC is safe"
https://mathissweet.substack.com/p/safety-concerns-around-far-uvc-radiation

“I have decided to do something different and make a shorter debunking post that’s basically in point form. One day I might make a longer, more detailed, more science-heavy one, because I could definitely say a lot more than I’ve said here! But ultimately, we can easily identify issues with the premises of the claim that far-UVC radiation is safe.
These (false) premises are:
• Far-UVC is safe because it’s safe for the eyes and skin.
• Far-UVC radiation is safe for the eyes due to the presence of tears and the fact that the cells on the surface of the eye are refreshed regularly and don’t live for long.
• Far-UVC radiation is safe for the skin because of the dead skin layer (called the stratum corneum or SC) on the surface of our skin, and also the short-lived cells below the SC that are destined to become the SC.
• Basically, this boils down to the idea that proteins in the tears and SC absorb the majority of the UV radiation, and even if some penetrates further, it would only cause DNA damage to cells that are destined to die soon anyway, meaning there’s no risk of the cells entering precancerous or cancerous states.
• Far-UVC does not cause DNA damage because it produces low or no pyrimidine dimers (one specific kind of DNA damage).
• Far-UVC does not cause redness or swelling of the skin so it is safe and non-damaging.
So what’s wrong with those statements?
• Our skin and eyes are not the only parts of our bodies at risk when it comes to UV radiation.
• Not everyone makes a normal amount of tears and/or tears with the same composition1. Various medications, medical conditions, environmental factors, etc. can contribute to dry eyes1. For those who make less tears or tears with less protein, the cells on the surface of the eye will experience a higher dose of radiation.
• The SC varies in thickness over the body2,3,4,5 and even does not exist on certain surfaces of the body, including parts of the genitals5,6,7 and parts of the inner surfaces of the eyes6, mouth6, throat6, nose8, genitals6,7 rectum6 and anus9.
• The SC varies in thickness from person to person2,3,4,5; tends to be thinner in female study participants than male participants2,10; is influenced by age11, humidity12,13, lotions14, etc.; can be at least partially removed through exfoliation15,16 and may be removed more easily in Asian people17. In one skin exposure study, older people and people with darker skin had longer-lasting DNA damage from far-UVC radiation than younger people and people with lighter skin [note: this study appears to have generative AI related errors in sections summarizing previous studies]18.
• Skin cells below the SC can enter a precancerous state, causing actinic keratosis, which if left untreated leads to a specific form of skin cancer in 20 % of cases19.
• Estimates of how much far-UVC radiation reaches skin cells below the SC rely on SC thicknesses that are generally higher than in many regions of the body3,4,20, particularly the face skin, and especially for female study participants. In some far-UVC skin exposure and skin model exposure studies, increased DNA damage is detected in cells below the SC, indicating it does penetrate cells below the SC18,21,22,23.
• While far-UVC generates less pyrimidine dimers compared to higher wavelength UV radiation, it appears to cause more double-stranded breaks than those wavelengths24. Importantly, double-stranded breaks are a more dangerous form of DNA damage than pyrimidine dimers due to being more difficult to repair25. Cancer develops through changes in a cell’s DNA, which can occur when DNA damage is not repaired properly.
• Filtered far-UVC radiation does not cause sunburn-like effects like redness or swelling. This was already known, does not mean it is safe, and should not count as evidence that it is safe.
What is missing from those statements?
• Far-UVC lamps are used under many different circumstances, including where unmasked people are opening their mouths to speak or to get dental work, where people may be naked, etc., and these scenarios expose tissues that are particularly vulnerable to damage that can lead to precancerous or cancerous states. Ultimately, no amount of UV radiation is safe, and even far-UVC radiation has the potential to cause cancer, especially in specific areas of the body.
• Without filters to reduce the longer wavelengths of UV radiation that are also produced by far-UVC lamps (ex: UVC radiation that is not far-UVC, ~235-280 nm), these lamps are especially dangerous, emitting significant amounts of non far-UVC radiation that is universally considered to cause cancer in humans and animals26 [I say universally to be a bit flippant, referring to the fact that some people believe/argue that far-UVC is safe, particularly the researchers funded by far-UVC lamp companies, who license their far-UVC technology to these companies, etc. lol].
• There is a lack of regulation around these lamps, meaning companies could even claim their products are filtered when they’re not, they could not go through vigorous testing, they could emit different doses of radiation than they claim, etc..
• There can be a lack of adequate safety information supplied with the lamps, including maximum daily exposure limits that take into account how far away the lamp is from the person.
• These lamps produce the toxic gas ozone, other harmful gasses and increase particulate matter in the air27,28–all of which are bad for human health, especially in people with certain medical conditions including asthma29,30.
• Many medical conditions, medications, injuries, fresh tattoos, eating certain foods, etc. increase the risks of UV exposure31,32.
• The risks of far-UVC exposure are increased for people with various marginalized identities, including ones that cannot be assessed visually. I strongly believe people should have to provide informed consent to enter a space with far-UVC lamps installed. I think it’s extremely irresponsible, anti-consent, inequitable and dangerous to not require this and to expose people to ultraviolet radiation without their consent and knowledge.
Alternative suggestions:
• I recommend air purifiers that rely on filters that effectively remove even very small particles from the air. While these can be loud at the highest and most effective settings, they do not pose the risk of causing cancer; do not create ozone, particulate matter, etc.; and tend to be cheaper than far-UVC technology.
• Of course, I also recommend ventilation and wearing high-quality well-fitting respirators that don’t have a lot of wear time nor a lot of don/doffs.
Some quick notes on one particular kind of misleading far-UVC study:
• On top of claiming far-UVC is safe, some far-UVC researchers also release misleading information around how effective the lamps are at inactivating airborne pathogens.
• For example, claims such as “inactivates 99 % of airborne coronavirus (not SARS-CoV-2) in 16 minutes”33 rely on data using aerosolized virus suspended in a simple buffer not containing protein, but aerosols exhaled by people have more complex compositions including proteins and glycoproteins from sputum, mucus, saliva, etc..
• As mentioned earlier, the claims around the safety of far-UVC radiation cite the fact that proteins in the tears and SC absorb a lot of the radiation, so this should be taken into consideration when it comes to designing experiments to assess the efficacy of inactivating pathogens in aerosols. In other words, proteins and other matter in aerosols that humans exhale can shield the pathogenic microbes in the aerosols from UV radiation to some extent.
• Thus, in real-world scenarios where people are exhaling pathogen-containing aerosols, far-UVC lamps will inactivate the microbes less effectively than in experiments using unrealistically simple aerosols that lack protein.
TLDR (repeating what I feel like are the most important points):
• No amount of UV radiation is safe, and even far-UVC radiation has the potential to cause cancer, especially in specific areas of the body.
• These lamps produce the toxic gas ozone, other harmful gasses and increase particulate matter in the air27,28–all of which are bad for human health, especially in people with certain medical conditions including asthma29,30.
• Many medical conditions, medications, injuries, fresh tattoos, eating certain foods, etc. increase the risks of UV exposure31,32.
• The risks of far-UVC exposure are increased for people with various marginalized identities, including ones that cannot be assessed visually. I strongly believe people should have to provide informed consent to enter a space with far-UVC lamps installed. I think it’s extremely irresponsible, anti-consent, inequitable and dangerous to not require this and to expose people to ultraviolet radiation without their consent and knowledge.”

#MaskUp #WearAMask #CovidRealist #CovidIsAirbone #LongCovid #YallMasking #DisabledLiberation #DisabilityJustice

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