Thanks to its decontaminating properties, a UV cleaning light is one of the most sought after products these days. 

UV radiation is proven effective when it comes to disinfection, but what does the upsurge in UVC lamp sales have to do with this pandemic? The coronavirus, caused by the SARS CoV-2 virus, is highly susceptible to ultraviolet radiation if given in the right dose and duration.

 The trouble is that we're surrounded by plastic and glass in our daily lives, and microbes thrive on these surfaces. Unlike our bodies and clothes, we do not have the luxury of cleaning all plastic and glass surfaces with water and detergent. 

Cleaning your phone or laptop with a microfiber or cloth can be an option, but it will not eliminate any microbes.

Companies like Puritize have recently come up with home UV light sanitizers that can effectively kill all germs, including coronavirus. They work best on smooth surfaces and kill microbes quickly.

As we mentioned, using ultraviolet light for disinfection is not new.  UV cleaning lights have been used to disinfect surfaces for 40 years, and they've generally proven to be quite successful.

Can Ultraviolet Light From The Sun Be Used For Disinfection?

UV light is broadly categorized into three classes: UVA, UVB, and UVC. All types of UV light can prove harmful to your skin, but the extent depends on the duration and level of exposure.

UVA light makes up 95% of the ultraviolet radiation that reaches the earth. It's generally not harmful, but prolonged exposure can cause premature aging, wrinkles, and spots. They are also linked to skin cancer. Also, UVA light is the least effective at killing bacteria and viruses and is therefore not particularly useful for UV lamps.

UVB light can penetrate deep into the skin, and it puts you at an increased risk of skin cancer and sunburn. It can damage the skin's DNA and quickly burn the skin, leading to pain. Using UVB lamps isn't a good idea because their radiation can penetrate deep into the skin, even if used indirectly.

UVC light has the shortest wavelength of all the three ultraviolet rays. They are highly dangerous for the human skin and eyes, but fortunately, the earth's ozone layer prevents them from penetrating the atmosphere. It is highly effective at disintegrating genetic material, such as DNA and RNA of viruses.

Sunlight with a wavelength of 100 to 400 nanometers is known as ultraviolet. The UVA and UVB rays we talked about are responsible for stimulating Vitamin-D synthesis in human beings and cause tanning and aging.

UVC light, which never makes it to the ground, ranges from 100 to 280 nanometers. It's a double-edged sword because it's harmful to humans on direct exposure and the most efficient form of UV radiation for inactivating viruses. It is routinely utilized in artificially powered UV disinfectant lamps.

UVB light from the sun and an artificial UV cleaning light work at vastly different speeds. Sunlight can kill microbes, but it works at a languid pace. You would need two to three hours of daylight in a mid-latitude location like New York to get the job done. As you go further north or move towards the winter solstice, it would take much longer.

Besides that, microbes need to be directly exposed to ultraviolet radiation to be inactivated. That is not possible in cities where buildings and other structures block out the light and cast shadows – only the part of the surface where the sunlight strikes directly would be disinfected. So, to put it shortly, sunlight is not an efficient way to disinfect surfaces.

Can A UV Cleaning Light Inactivate The SARS-CoV-2 Coronavirus?

Though UV light's effectiveness in killing bacteria is known for more than a hundred years, it was in the 1940s that ultraviolet lamps were first used to prevent the spread of measles. UV light's ability to inactivate viruses depends on two things; the radiation dose and duration. 

A UV cleaning light that uses UVB and UVA radiation isn't effective at inactivating the coronavirus. That only leaves us with UVC lights, and luckily the mechanism it uses to destroy the virus is pretty simple. The UV light destroys the coronavirus's outer lining, making it unable to replicate and render it inactive. 

Most lamps use UVC light to kill microbes on surfaces. UVC radiation can neutralize a virus only through direct exposure. Many UV lamps used in homes are of low dose and may take much longer to inactivate microbes. 

UVC light is routinely used to sterilize equipment in hospitals and kill germs and bacteria. Another interesting use of UVC light is in disinfecting water bottles for infants. 

Some people might erroneously think that they can substitute handwashing with UV sanitizers. UV cleaning lights and sanitizers are only meant for objects and surfaces. In no case are they meant to be used on human skin or other living cells.

Can A UV Cleaning Light Be Harmful To Humans?

A UV cleaning light does not pose health risks to humans if used carefully. However, that does not mean that UV lamps have not harmed people. There have been occurrences of skin burns due to malfunctioning UV lamps inside homes. 

There are health and safety risks associated with using a UV cleaning light at home. It all depends on the dose and duration, as well as the UVC wavelength of the lamp. As far as direct contact is concerned, UV lights should be kept away from humans and animals alike.

How Effective Are Other Methods Of UV Radiation?

Since we've talked of UV radiation for disinfection purposes, it's natural to wonder if other electromagnetic radiation, such as ultrasound and visible light, can play the same role? And how do they measure up to UV light disinfection?

Let's look at a few examples

Ultrasonic Disinfection

While ultrasound waves may not be useful for killing coronavirus, they still are used for disinfection purposes. Among the many applications of ultrasound waves, one such example is water treatment. Ultrasound waves are used to target algal growth in water. The frequency of the wave is tuned to target the cell walls of the algae. It's useful for keeping water clean in pools and ornamental ponds.

LED Blue Lights For Disinfection

Recent research has unearthed the possibility of LED blue lights as a safer disinfecting alternative to ultraviolet light. LED lights with a blue-light wavelength can be used to render MRSA microbes inactive. The LED blue light is used to excite molecules within the microbes through photo-activation, which produces reactive oxygen species that kill the cells.

High-Intensity UV Radiation

UV radiation is an effective disinfectant because of its strong germicidal ability. It was routinely used for water disinfection in the early part of the 20th century, only to be replaced by chlorination. High-intensity light can be useful in inactivating bacteria and viruses as well as protozoans.

Endnote

UV light can be used effectively to disinfect surfaces and objects. Past use has proven that it works against viruses like the COVID-19 and SARS.

However, as mentioned earlier, not all UV cleaning lights deliver as promised. Most are low-dose ineffective prototypes that might claim to kill all microbes but don't.

 Also, they might end up doing more harm than good. 

So before buying a UVC cleaning light for your home, ensure that you understand all its specifications and then make an informed choice before purchasing a UV disinfectant for yourself.