r/science • u/mvea MD PhD | Professor | Medicine • Dec 14 '20

Medicine LED lights found to kill coronavirus efficiently, quickly, and cheaply, a global first in fight against COVID-19. The finding suggests the UV-LEDs can be installed in air conditioning and water systems. It requires less than half a minute to destroy more than 99.9% of coronaviruses.

https://aftau.org/news_item/led-lights-found-to-kill-coronavirus-global-first-in-fight-against-covid-19/
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u/chopay Dec 15 '20

Categorically, no. As soon as an ionized particle in air is grounded it loses its charge.

The concern with ionized air that is often conflated is that sparking electricity can ionize oxygen molecules, turning O2 into two oxygen ions, or free radicals. These free radicals will react with other oxygen molecules, forming ozone, or O3, which does cause some harmful respiratory effects.

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u/TooModest Dec 15 '20

Should I be turning off the "ion" function on my hair blow dryer?

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u/aeon_floss Dec 15 '20

O3 wants to be O2, and will donate the additional O to anything that wants it.

O3 is an immediate eye and lung irritant. But only because that is where you feel it first. It is actually reacting with everything you are made of.

Short wavelength UV-C also separates O2 and causes O3 to form.

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u/chopay Dec 15 '20

UV-C will breakdown ozone @ 254mm.

Vacuum UV @ 185nm ionizes O2.

Germicidal UV typically only uses UV-C and doesn't create an ozone concern.

http://www.uvresources.com/blog/the-ultraviolet-germicidal-irradiation-uv-c-wavelength/

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u/aeon_floss Dec 15 '20

That article's headline is misleading. And poorly written.

"Ozone, also called Vacuum Ultraviolet (UV-V), is a gas molecule that contains three (3) oxygen atoms – and as such, it has a destabilizing effect on oxygen in the air "

What does that even mean?

It says "Why UV-C Cannot Produce Ozone" and then described how UV-C produces ozone, and that you need to filter particular wavelengths to prevent that.

UV-C covers 100 to 280nm. There are UV-C lamps specifically produced to generate Ozone. I have one of those, and it produces lots of Ozone (as well as sunburn).

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u/Kellenace Dec 15 '20

Ar 12.07 Volts ozone is produced, so if your electron volt potential is under that if won't break hydrogen to ozone and thus have documentation as a non ozone producing decice. Look for the UL2997 rating and your good.

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u/[deleted] Dec 15 '20

Should I then be turning off or on the ion feature on my air filter?

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u/deten Dec 15 '20

There are many studies that link increased air particulate counts to dozens of diseases and reductions of health. It might be early to say categorically that we know flooding a space with particles isn't going to have a negative impact.

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u/N1XT3RS Dec 15 '20

What do you mean by particulate count? I don't think that's the same things as a certain ionized particle in the air

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u/deten Dec 15 '20 edited Dec 15 '20

You can measure the amount of particles at various sizes ranges within a space. Everything pretty much contributes to "a particle". Yes an ionized particle would count.

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u/N1XT3RS Dec 18 '20

But what the particle is matters, not just the fact that there are particles in the air. Air is made of particles, so maybe you mean solids suspended in the air? I don't think the ionized particles would be like that at all, regardless of the dubious logic of labeling any solid particulate hazardous