Poll: How many of you are hanging your face masks on your rearview mirrors?

[sl8]

42. I had always thought that all UVC was dangerous to humans, until a couple of months ago.

A couple of months ago there was a flurry of articles about using certain wavelengths of far UVC for sanitizing, saying that those particular wavelengths were safe. If you google"far UVC safe", you'll see what I mean. They may have all been based on the same study, I'm not sure.

Here's an excerpt from a recent study:
https://www.nature.com/articles/s41598-020-67211-2

[...]
Ultraviolet (UV) light exposure is a direct antimicrobial approach4 and its effectiveness against different strains of airborne viruses has long been established5. The most commonly employed type of UV light for germicidal applications is a low pressure mercury-vapor arc lamp, emitting around 254?nm; more recently xenon lamp technology has been used, which emits broad UV spectrum6. However, while these lamps can be used to disinfect unoccupied spaces, direct exposure to conventional germicidal UV lamps in occupied public spaces is not possible since direct exposure to these germicidal lamp wavelengths can be a health hazard, both to the skin and eye7,8,9,10.

By contrast far-UVC light (207 to 222?nm) has been shown to be as efficient as conventional germicidal UV light in killing microorganisms11, but studies to date12,13,14,15 suggest that these wavelengths do not cause the human health issues associated with direct exposure to conventional germicidal UV light. In short (see below) the reason is that far-UVC light has a range in biological materials of less than a few micrometers, and thus it cannot reach living human cells in the skin or eyes, being absorbed in the skin stratum corneum or the ocular tear layer. But because viruses (and bacteria) are extremely small, far-UVC light can still penetrate and kill them. Thus far-UVC light potentially has about the same highly effective germicidal properties of UV light, but without the associated human health risks12,13,14,15. Several groups have thus proposed that far-UVC light (207 or 222?nm), which can be generated using inexpensive excimer lamps, is a potential safe and efficient anti-microbial technology12,13,14,15,16,17,18 which can be deployed in occupied public locations.

[...]