UVC, germicidal ultraviolet (UV) light, reduces the person to person transmission of viruses through the air, by killing the viruses while they are in the air as well as on surfaces exposed to UVC light rays.

While you can’t use UVC rays to replace hand sanitizer to sanitize your hands. you can use a UVC lamp or bulb to effectively kill bacteria, mold, and viruses on surfaces and in the air.  If you’ve stocked up on disinfectant wipes and aerosol sprays and are beginning to run low, or are having a difficult time finding these products, you could use a UVC lamp or bulb to essentially get the same (if not better) results.

Surface wipes and sprays are only effective if the object or surface remains visibly wet for a specified period of time.  With a UVC light at a 6 inch distance, up to 99% of microorganisms can be killed within a few seconds.  Rooms can be treated within 30-60 minutes, depending on size.  And because most UVC bulbs claim to have a lifespan of up to 50,000 hours,  you can actually save money over the cost you might spend replenishing wipes and sprays.

With UVC you can sanitize masks, cell phones, countertops, toothbrushes, keyboards, shoes and pretty much any object or surface.  You can even sanitize the air in a room or the entire room itself.  There are some basic precautions necessary when using a UVC light, but the benefits of using a light versus sanitizing products definitely is worth the effort.

UVC rays can also be used to purify water, kill household pests, inactivate mold spores, air purifier, odor remover,

You can purchase portable UVC wands, bulbs and lamps to disinfect objects and surfaces.  When you are comparing products, make sure the item description specifically mentions that the item produces UVC rays.  Several items we reviewed were actually black lights, which do not provide germicidal effects like that of UVC.  Ensure that the product description specifically states the nonometers (wavelengths) the light emits.  Ideally, it should have 200 to 280 nm.

In researching the best buying options for a UVC light in response to coronavirus, we compared wands and light bulbs.  UVC wands have been proven to be effective against bacteria and viruses.  These are great for spot-treating specific areas such as countertops, small objects such as masks and cellphones. And they are portable, so you can use them to sanitize surfaces while traveling.

We opted for the light bulb because we could disinfect specific objects and surfaces, but also use it to disinfect a larger areas such as entire rooms.  The option to remove airborne pathogens was also a huge plus.  We chose a 60 watt bulb that could be inserted into a standard light socket.  They also offer these bulbs with remote controls so that you can safely turn the light on and off without having direct contact with the UV rays.  Due to the concerns of direct exposure, you should definitely get one with a remote control.

Without the remote control, our plan is to use an extension cord so we can safely turn on/off the light from outside of a room.  For disinfecting specific objects or surfaces, we’ll use the bulb in a work light clamp reflector. We also purchased UVC safety glasses that have 99% UVC protection.

Wattage is important if your goal is to sanitize larger areas.  If you are just shooting for object disinfection, a 7 or 11 watt wand used within a few inches of the object should be sufficient.  Be sure to read the product’s specifications before purchase.  And again, make sure you aren’t buying a black light.  We found many misleading products claiming to sanitize that were black lights and not UVC emitting lights.  Again, ensure that the product description specifically states the nonometers (wavelengths) the light emits.

For purchase links for portable wands, click here.

For purchase links to the bulb we decided to buy, click here.  Our light bulb is identical to this article’s featured image.

What Is UVC?

The three main types of UV rays are UVA, UVB, and UVC. Their light wavelengths are measured by nanometers (nm)

  • UV-A (long wave) from 315 to 400 nm
  • UV-B (medium wave) from 280 to 315 nm
  • UV-C (short wave) from 200 to 280 nm

Because UVC light is a high intensity light, UVC light effectively kills pathogens and microorganisms by damaging their DNA, making them unable to replicate (reproduce), which leads to cell death.

How Does UVC Light Work For Disinfection?

Wavelengths between 185-254 nanometers are considered germicidal because they have the shortest wavelength, highest energy, and can kill pathogenic microorganisms in the air and on surfaces. This makes the UVC spectrum the most efficient for killing viruses and bacteria.

UVC lamps can kill up to 99.9% of most viruses, bacteria, yeasts, and mold spores and help prevent future mold growth.  Definitely an option if you have mold due to water damage in your home.

How effective the UVC light is, is determined by how much time and how close objects/surfaces are to the light. Objects that are closest to the light receive the highest intensity and require shorter period of time to kill microorganisms. Objects that are further away from the light can still be disinfected if their exposure time is increased.

What Are The Advantages Of Sterilizing Using UVC Light?

  • Disinfecting with UVC light eliminates the need to use harsh or potentially toxic chemicals, and no chemical residues are left behind.
  • UVC light can sanitize both the air and surfaces.
  • Entire rooms can be disinfected; bathrooms, bedrooms, kitchen, laundry rooms and hampers, etc.
  • Items that might be damaged using traditional disinfectants can be sterilized using UVC; facial masks, mail, delivered packages, mobile phones, tablets, keyboards, electric shavers, etc.
  • In killing bacteria, you can also eliminate the odors they cause; laundry hampers, refrigerators, freezers, shoes.
  • At a distance of 6 inches away from a surface, UVC light can kill the average bacteria within 10 seconds.
  • UVC light can sanitize hard-to-clean nooks and crannies that might be missed with traditional cleaning methods.
  • UVC light is effective against “superbugs” that are resistant to antibiotics.
  • It can inactivate 90% of spore-forming bacteria within 40 seconds.
  • UVC lights can be reused as often as needed and most bulbs last up to two years whereas traditional disinfecting products need to be replenished.

What Are The Disadvantages Of Sanitizing Using UVC light?

  • A room that has been disinfected with UVC can have some lingering odors; these odors will dissipate once the room is aired out.  This odor is the result of the breakdown of dust during disinfection.  80% of dust in a room consists of dead human skin and hair cells.  As these cells break down, they release chemicals which cause these odors.
  • UVC rays are a high intensity light and direct exposure is harmful to all living organisms (humans, pets, plants), not just bacteria and viruses.
    • We purchased Carhartt safety sunglasses that were labeled as 99% protection for UVA/B/C protection.
    • No human, pet or plant should be in a room that is being sanitized with UVC light blub or room lamp.
    • Keep portable UVC wands faced downward towards the surface you are sanitizing.
    • When sanitizing an entire room with a bulb or lamp, use a timer or remote switch so you can turn the light on and off from a safe distance.
    • If you need to manually turn on a UVC light bulb, wear clothing that covers all exposed skin and protective goggles for your eyes.
    • If you are concerned about being in close proximity to UVC rays, you might consider Far-UVC lights and wands. They emit lower doses of UVC 200-222 nm, which cannot penetrate the outer dead (non living) layers of human skin or the eye, but are still effective at inactivating bacteria and viruses.
    • You must faithfully follow the manufacturers’ instructions on light-source distance, exposure time and safety precautions for any device you purchase.
    • UVC light is much more intense than sunlight. Direct exposure can causes skin cancer and and eye problems.
  • Only organisms in direct line of the UVC light rays will be sterilized (light can’t turn corners or go around objects)
    • Rotate the light’s location in a room to reach all areas, or use several lights at different angles
    • The further away an object or surface is from the light, the more exposure time is needed for sterilization.  Objects that are further away from the light will still be sanitized, they just need a longer exposure period if they are further away.

What Type Of Coverage Will Different Watt Bulbs Or Lamps Provide?

A 15 watt light bulb will cover approximately 100 square feet.
A 30 watt light bulb will cover approximately 200 square feet.
A 60 watt light bulb will cover approximately 400 square feet.

How Long Will It Take To Sanitize A Room, Object, Or Surface?

The required time for killing different species/microorganisms varies due to their size and shape, how powerful the light or lamp is, how close the surface is to the light rays, and how long they are exposed. Follow the manufacturer’s recommendations related to distance and surface exposure time. For a typical 60 watt light bulb:

  • 5 minutes for objects or surfaces within 3-4 feet of the light, such as masks, countertops, cups, bottles, cell phones, clothing, etc
  • 5 minutes to treat the air in a 50 square foot room
  • 15 minutes to treat the air in a 200 square foot room
  • 30-60 minutes to treat the air in a 400 square foot room

Purifying Water Using UVC

UVC is ideal for disinfecting water because it quickly kills microorganisms, and even protozoa that chloride can not kill.  UVC does not change the odor, taste, or PH of water, does note leave behind any chemical byproducts, and is considered environmentally safe when used properly.  The limitations of purifying water using UVC is that the water must already be clear (cloudy or murky particles in the water will block the rays from effectively killing all microorganisms), UVC rays do not remove heavy metals, chlorine, does not filter out these microorganisms once they have been killed, and it can not remove environmental contaminates (oil, chemicals, etc).   Water containing any of these substances should be filtered before using UVC.

References:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703853/
https://www.infectioncontroltoday.com/environmental-hygiene/uv-lights-germicidal-properties-aid-fight-against-hais

Is UV Sterilization Effective for Viruses and Bacteria?


https://www.eliteelectricandair.com/wp-content/uploads/2020/03/NH_NOVEL-CORONO-VIRUS-flyer-1.pdf
https://www.sciencedirect.com/science/article/pii/S1684118217302001

Killing Bacteria with UV Light


https://www.insider.com/does-uv-light-kill-germs
https://www.americanultraviolet.com/uv-germicidal-solutions/faq-germicidal.cfml
https://www.ajicjournal.org/article/S0196-6553(14)01086-4/abstract?cc=y=
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3292282/
http://prolight.info/pdf_specs/Philips_UV_tech_brochure.pdf

207-222 nm Far-UVC Light Can Slow Spread Of Novel Coronavirus COVID-19


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4260232/
https://www.uvccleaningsystems.com/cm/dpl/downloads/articles/16/Root_Cause_of_UVC_Odor.pdf

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