Are Vital Vio Violet or UVA LEDs a safe and effective technology for reducing airbone transmission of viruses?

Summary: These lights are slightly antimicrobial, have poor CRI, and may cause minor eye damage. The feasible power levels are far too low to have much (if any) value against viruses such as SARS-CoV-2.

Vital Veo sells an LED lighting product that it markets as antimicrobial through the use of violet light. A typical white LED is based on a monochromatic blue LED combined with a phosphor pump to achieve a variety of wavelengths across the visible light spectrum (note that this curve has a 93+ CRI).

ARC600SpectrumGraph.png

Since the eye only has 3 cones to perceive color, as long as the weighted signals going into each color balance out, the light will come off as white, even when the spectrum looks irregular. Vital Veo's approach is to take advantage of this by adding another LED into the mix at the very edge of the visible spectrum around 400nm. Their patent describes using an LED with light in the range of 380-420nm for 20% of the overall light output, with the rest of the spectrum designed to balance out that peak to prevent the color from appearing as violet. They have an option that allows the lights to switch to pure violet when the room is unoccupied, either with a higher intensity of violet, or with the rest of the spectrum switched off to save on electricity. It is used in violet-only mode when the room is unoccupied for the conveni

What is a typical amount of lighting? 400 lux is a common indoor office level. 400 lux is 400 lumens per square meter. This LED will be a bit less efficient so we'll assume 65 lumens/watt, which equates to 6.15 watt per square meter, or 0.615 mW/cm^2. 20% of this is 0.123 mW/cm^2 so our dosage is 7.38 mJ/cm^2 per minute, or 443 mJ/cm^2 per hour, or just over 10 J/cm^2 per day.

There are a number of studies looking at the amount of 405nm light needed to inactivate bacteria, and unfortunately, this is not enough. Tens to hundreds of joules per square centimeter are needed for substantial inactivation (~100,000x more than UVC light). Getting enough power from a narrow spectrum within a white light is a challenging problem and this clearly indicates the premise of the Vital Veo lights is not sound. It seems the antimicrobial activity will be fairly negligible, though greater than 0. That being said, the antimicrobial of any light will be greater than 0. We saw a study that showed that with tens of joules per centimeter squared of 470nm cyan light, the same bacteria were inactivated to a similar extent. So you'll probably get a better outcome with just doubling the brightness of your lighting system. Is Vital Veo a scam? -- we'll cautiously answer "no" to that, but it definitely is a grift.

It is not very effective. Is it also not safe? They state that there is no UV in their products and there are 2 ways they could be making this claim: 1) they have a filter that cuts off light below 400nm, or 2) they take the less commonly used definition of visible light as being 380-780 rather than 400-700nm so that they UVA light can instead be classified as violet. It's certainly more damaging than the 420-450nm harsh blue light you hear people concerned about, but that's a gradual effect, which some people think should not be as much of a concern so we wouldn't call it dangerous.

Is at least a decent light for illumination purposes? Alas, no. It is probably the worst light we have ever seen when cost is factored in (around $200-300 / per 4ft tube or $5k per 1000 square ft). At these prices you can get ultra-high-end lighting with near perfect fidelity index. Instead, you end up with a lousy 80 CRI that you could easily find under $10/tube. 80 CRI is not equivalent to a "B-". As the spectrum above shows, even 93+ CRI can be fairly poor. This is because CRI itself is a poor and obsolete metric for evaluating the quality of light (look for fidelity index instead).

What if you want something like the Vital Veo for security theater purposes -- is there a more cost-effective option? Absolutely! Instead of a blue LED phosphor pump you can get one that uses a violet LED. In fact, these violet phosphor pump LEDs are the ultra-high-end option and pretty much the only way to get a decent light spectrum with a high fidelity index. Plus, they have a violet spike, without any UVA. Just spec your facility for 1000-2000 lux instead of 500-1000 lux to compensate for that violet spike being smaller and you'll have an absolutely stunning indoor environment, which you can claim does whatever you wanted to be able to say you were doing with Vital Veo. The violet LED was invented at SORAA, and you can also look at Nichia (Optisolis), Toshiba (Sunlike), and YUJILEDs (VTC series) if you want to go this route. [Disclosure: a key person early on at SORAA who is no longer there was previously an advisor to a founder of Reflow Labs in a company completely unrelated to lighting, which may cause some bias]

See our other articles or take a look at our research paper summaries.

Learn more about the landscape of technologies marketed as making air safer: 1) Far UVC; 2) Radical Oxides e.g. Hydrogen Peroxide; 3) Ozone

Read the Reflow Labs Airsafe White Paper

See the key FAQ pages provided by a team of scientists on COVID-19 transmission and preventive approaches:

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