Can All the UV LED Products Be Used for Sterilization?

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Zayn
Posts: 3
Joined: Wed Jan 27, 2021 8:51 pm

Can All the UV LED Products Be Used for Sterilization?

Post by Zayn »

UV LED ultraviolet products is dramatically increasing in demand due to the spread of COVID-19. However, some people mistakenly believe that all of UV LED products have disinfection and sterilization effects, there are even examples of using nail UV lamps to disinfect masks. In fact, the UV wavelength of this product cannot be disinfected at all. Since different wavelengths of UV have different effects, if you want to effectively sterilize and disinfect, you must first select the correct UV wavelength, which starts with the classification of UV and ultraviolet radiation.

According to ISO-DIS-21348 classification instructions, the UV wavelength range is below 400 nm, which can be divided into long-wavelength UVA, medium-wavelength UVB and short-wavelength UVC. UVA wavelength ranges from 315 nm to 400 nm, mainly used in UV curing, ink printing, PCB exposure, nail art, banknote recognition and other industrial and consumer fields; UVB wavelength ranges from 280 nm to 315 nm, mostly used in ultraviolet light therapy, medical care aspect.

Nail art UV lamp has UVA wavelength, which cannot sterilize masks

As for the actual ultraviolet light that has the effect of disinfection and sterilization, it is UVC, with a wavelength of 200 nm to 280 nm, which is the shortest wavelength and strongest ultraviolet light. It can destroy bacteria, viruses, molds, spores and other microbial cells through short-term irradiation. The internal DNA or RNA structure prevents cells from reproducing and dying, achieving disinfection and sterilization. Therefore, they are widely used in surface, water, air purification, sterilization and disinfection.

In the past, UV mercury lamps were mostly used for sterilization technology, but they were large in size, high in energy consumption and easy to cause pollution. Later, under technological evolution, they were gradually replaced by UV LEDs. Not only were they small in size and high in efficiency, they were also more flexible and versatile in product design Low consumption, long life, no chemical residues, safer and more environmentally friendly.

Chris S.
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Joined: Sun Apr 05, 2009 9:55 pm
Location: Ohio, USA

Re: Can All the UV LED Products Be Used for Sterilization?

Post by Chris S. »

I agree that only UVC light is probably practical for virus disinfection, and that LEDs are a very promising source for this light. Also that there is a scary amount of misinformation out there.

Not only this, but there is too often little talk about achieving the necessary UV dose (intensity and exposure time)--there are definitely minima for effective sterilization.

When the pandemic began and PPE was in short supply, I did a back-of-the-envelope design of a face mask to sterilize incoming and outgoing air with UVC. At the time, there was lethal dose information for SARS-CoV-1, the virus that caused "classic SARS," and I used that. I suspect that by now, this information is known for SARS-CoV-2, the related virus causing our current Covid-19 pandemic. From the numbers I got, my sense at the time was that such a mask would require a backpack to support it, with a maze of air tubes, flooded by UVC light, of a length, diameter, and airflow speed calculated to administer the lethal UVC dose to the air flowing through it, plus a safety margin. The device would also need fans to propel the air at the proper speed, and to provide a comfortable freedom of breath for the wearer. There should be prior filtration to prevent smoke, dust, or moisture particles from interfering with viral exposure to the UVC light. It would require substantial battery power to run all this, likely a bank of rechargeable 18650 batteries that could be swapped in and out. Feasible indeed, though not quite trivial.

Such a backpack might be practical for some front-line medical workers, at least.

What stopped me from going beyond the back-of-the-envelope stage was finding an OxCam professor who claimed to have designed something that sounded similar--surely with far more ground work than I had done--and said he was trying to get a company to manufacture it.

For removal of virus particles from the air in offices, warehouses, and the like, I've heard that electrostatic viral precipitation, retrofitted inside the ductwork, is both effective and more cost efficient than UVC treatment.

--Chris S.

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