Researchers Create Air Filter that Can Kill the Coronavirus

[sman]

Researchers Create Air Filter that Can Kill the Coronavirus

https://uh.edu/news-events/stories/july-2020/07072020ren-coronavirus-filter.php

“This filter could be useful in airports and in airplanes, in office buildings, schools and cruise ships to stop the spread of COVID-19,” said Ren, MD Anderson Chair Professor of Physics at UH and co-corresponding author for the paper. “Its ability to help control the spread of the virus could be very useful for society.” Medistar executives are is also proposing a desk-top model, capable of purifying the air in an office worker’s immediate surroundings, he said.

“This novel biodefense indoor air protection technology offers the first-in-line prevention against environmentally mediated transmission of airborne SARS-CoV-2 and will be on the forefront of technologies available to combat the current pandemic and any future airborne biothreats in indoor environments,"  Cheema said.

[David H. Lipman]

So ?
UVC kills pathogens such as Viruses, Bacteria and Protozoa and even Mold.  With the advent of high power Light Emitting Diodes (LEDs) that emit 100 ~ 280nm ultraviolet light, one can easily retrofit any air duct with an array of UVC LEDs and destroy COVID and other infection agents.  This can be done in Air or Water.

This is not new.  Only the application of UVC LEDs are new.  UVC emitting light tubes have been around for 100+ years and have been used in purification processes around the world.  In fact it is used to make Clams that are unfit for human consumption fit for human consumption in just 48 hours which is known known as the Clam Depuration process.

References:
https://www.robotlab.com/store/connor-uvc-disinfection-robot
https://njbiz.com/united-seacoast/
https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation
https://www.cuimc.columbia.edu/news/can-uv-light-fight-spread-influenza
https://materion.com/resource-center/newsletters/materials-news-stats-and-chats/killing-germs-with-leds
 

[sman]

@David H. Lipman 

Grtgs boss, how r you ? (hope u will remove the pm msg blocking).

And boss, i did come across UV use but it was said to be dangerous as per a report long back. and I dug that report again.

There’s only one type of UV that can reliably inactivate Covid-19 – and it’s extremely dangerous.

https://www.bbc.com/future/article/20200327-can-you-kill-coronavirus-with-uv-light

“You would literally be frying people,” says Dan Arnold, laughing in disbelief. 

[David H. Lipman]

Of course UVC can be dangerous. 

That's why it kills/breaks down simple celled organisms and viruses.  When human skin is exposed to UVC it can cause "Sun Burn" and prolonged exposure can lead to Skin Cancer and if viewed by the eyes can cause cornea injury ( aka; “welder's eye” ) .  However UVC is a type of surface acting agent.  It's ability to penetrate below a surface is extremely poor.

In the Clam Depuration process or within an air duct the UVC light source is in a closed system.  

When it is used by a Hospital Robot type of application, the robot is used to enter a hospital room and bathe the surfaces in UVC light when there is nobody in that room ( usually after a patient has left the room ).

When used as a fixed appliance, such as in Subway Cars, the light is only used during scheduled off-hour maintenance.

There is one instance where I can see UVC light  being used in a non-closed system.  I can envision a meat processing facility where the assembly line is bathed in UVC light along with the visible spectrum.   However the people on the lines are already wearing coveralls and gloves so their skin is covered and the only thing remaining is to wear a UVC filter visor to protect the eyes and face.  Thus the COVID cloud in the air can be mitigated as well as on all bathed surfaces.  This will not only be good for the personnel on the line but will also kill Escherichia coli ( aka; E. Coli ), Lysteria and other food borne pathogens.  While it would not affect colonies within the meat being processed, it will help keep surfaces clean and thus reduce the spread of the pathogen within the meat processing plant.

 

[sman]

@David H. Lipman

The bottomline is UVC is very dangerous.

"To use UVC safely, you need specialist equipment and training. The World Health Organization (WHO) has issued a stern warning against people using UV light to sterilise their hands or any other part of their skin."

So, the Air filter technique holds more promise (and if far UVC tech comes out safer, it will also be a good option for Covid. 

Far-UVC light could be 'game changer' in coronavirus fight, researchers say

https://www.foxbusiness.com/technology/far-uvc-light-coronavirus

 

[David H. Lipman]

3 hours ago, sman said:

"To use UVC safely, you need specialist equipment and training. The World Health Organization (WHO) has issued a stern warning against people using UV light to sterilise their hands or any other part of their skin."

Right.  Bleach ( Sodium Hypochlorite ) is also very dangerous. 

Yet 8 drops of bleach can be added per gallon of impure water to purify it of pathogens and make it potable. 
If that water is boiled first, two drops of bleach per gallon of water will keep it clean of pathogens.

The Air filter technique does not hold more promise as it restricts air flow and heating the Nickel foam to close to 400 Deg F. would consume more energy and would be more difficult to retrofit.  Think about it.  You are heating a metallic foam that passes its heat energy, measured in BTUs,  to the surrounding air.  That is fine in the winter months but in the summer months the air conditioning units would have to compensate that added BTU load in its facility cooling system.  However, both are closed systems.  UVC light in an air duct would allow unrestricted air flow and would be concealed such that you would not be influenced by the ultraviolet light.  The fact that I have discussed UVC LEDs means that they would consume less power.  Even lower than compact fluorescent tubes or other former emission techniques that would have greater losses in the form of heat.  LEDs would still generate heat but that heat can be dissipated into the dead/non-circulating air space.  Best of all, LEDs can be tuned to emit light in the most effective wavelengths.  
 

Edited July 11, 2020 by David H. Lipman
Edited for content, clarity, spelling and grammar

[sman]

@David H. Lipman

With UV's already around, why would one go for airfilter's mode? It's the heat and susceptibility of COVID to heat,which has prompted to take upthis route and succeed. with HVAC systems with air filters tokillanu airvorne pathogens quickly and safer environment.

 

 

[sman]

@David H. Lipman

More on the Air filter tech in https://www.forbes.com/sites/robertglatter/2020/07/08/super-heated-air-filter-can-catch-and-kill-coronavirus/#978f3842a066

Super Heated Air Filter Can ‘Catch And Kill’ Coronavirus

Garrett K. Peel, MD, Executive Vice President and Managing Director at Medistar, said that the nickel heated filter will be compatible with MERV-11 and MERV-13 specifications as part of an HVAC system, “meeting criteria and FDA guidance for 510-K application,” assuring safety in light of Covid-19.

“Existing HVAC systems can easily be retrofitted with the biodefense filter that is proven to catch and kill SARS-CoV-2 on contact,” Peel emphasized. “Other technologies such as HEPA only catch the virus, while this new filter has been proven to not only catch, but also kill.”

And while the temperatures used to heat the filter approach 200 degrees Celsius (392 degrees Fahrenheit), it’s pulsatile in nature and does not constitute a fire hazard, Peel said. “The filter is a high performance metal and has been shown to not affect the ambient air. the frame is in a fire retardant/ resistant structure to withstand temperatures that exceed 1,000 degrees Fahrenheit,” he added.

Yah. the report doesn't say anything on the addl load on HVAC systems, but that it;s safe and effective, with the caution to also use masks and other precautions for protection. 

[David H. Lipman]

As a follow-up, I wanted to report why LED emission tuning is effective.  It is because the physical size of the COVID particle is close to the wavelength spectrum of  UVC being 100 ~ 280nm.  It turns out COVID is physically 80 ~ 120nm in size.  Thus it really isn't UVC that is effective but what is called Vacuum Ultraviolet which has a spectrum of 10 ~ 200nm.  By tuning an array of LEDs to emit a spectrum range associated with the physical size of  COVID particles, an overpowering amount of Luminous flux in an air duct disinfection system is very effective in breaking down the COVID particle rendering it inert. 

Reference:  
https://www.researchgate.net/figure/Coronavirus-particles-80-to-120-nm-in-diameter-identified-in-in-fected-HRT-cell_fig1_12225613
https://www.nature.com/articles/srep18030

 

 

Edited July 17, 2020 by David H. Lipman
Edited for content, clarity, spelling and grammar

[sman]

Tks. @David H. Lipman for the update. Would like to see UV systems developed esp. Far UVC coming up in this regard. Air filter is also an option, whichever comes up with practical and effective use.