A UV light shines down on a small room with a blue glow. Share on Pinterest
LeafenLin/Getty Images

Ultraviolet (UV) light is a type of radiation. It has more energy than radio waves or visible light but less energy than X-rays or gamma rays.

You can be exposed to UV light via natural sunlight or through human-made sources like tanning beds.

UV light has been used as a means to kill germs like bacteria and viruses. You may have also heard of its use for killing SARS-CoV-2, the new coronavirus that causes COVID-19.

In this article, we’ll explore how UV light is used to kill germs, how effective it is at eliminating the new coronavirus, and more.

There are several types of UV light. They’re classified according to how much energy they have.

UVC light is the type of UV light that’s most effective at killing germs. It can be used to disinfect surfaces, air, and liquids.

UVC light kills germs like viruses and bacteria through damaging molecules like nucleic acids and proteins. This makes the germ incapable of performing the processes that it needs to survive.

UVC light can be used to kill the new coronavirus, SARS-CoV-2. Let’s look at what the research has discovered about UVC light and this coronavirus so far.

UVC light for disinfecting liquids

A recent study in the American Journal of Infection Control (AJIC) investigated using UVC light to kill large amounts of the new coronavirus in liquid cultures.

The study found that UVC light exposure completely inactivated the virus in 9 minutes.

UVC light for disinfecting surfaces

Another study, also published in the AJIC, looked at using a specific type of UVC light to kill SARS-CoV-2 on laboratory surfaces. The study found that the UVC light reduced the live coronavirus by 99.7 percent in 30 seconds.

The type of UVC light used in this study is called far-UVC light, which is UVC light between the wavelengths of 207 and 222 nanometers.

Far-UVC light is still damaging to germs but is less of a hazard to your skin and eyes than other types of UVC light.

UVC light for disinfecting air

One study, published in the journal Scientific Reports, explored using far-UVC light to kill two types of human coronaviruses in the air. These two coronaviruses, 229E and OC43, can cause the common cold in humans.

Based off their results with these viruses, researchers estimated that, when applied to current regulatory standards, far-UVC light could kill 99.9 percent of airborne coronaviruses in about 25 minutes. They believe that these findings would extend to SARS-CoV-2 as well.

Summary

UVC light can effectively kill SARS-CoV-2 or other coronaviruses in liquids, on surfaces, or in the air. Due to the fact that it presents less of a health hazard, far-UVC may be a good option for disinfection.

Because it can effectively inactivate the new coronavirus without using chemicals, UVC light is an attractive option for disinfection. Special lamps that emit UVC light are typically used for this purpose.

Currently, the use of UVC light for disinfection is mostly limited to healthcare settings to disinfect things like:

  • surfaces
  • equipment
  • operating rooms
  • personal protective equipment (PPE), such as N95 face masks

One of the downsides to UVC light is that it needs direct contact to be helpful. That means that if an area is in shadow or covered by dust, UVC light will be less effective at killing germs that may be present.

While UVC light can quickly kill SARS-CoV-2, the Food and Drug Administration (FDA) notes some additional risks for using it at home:

  • The optimal length of exposure, wavelength, and dose of UVC light for killing SARS-CoV-2 is yet to be determined.
  • Exposure to some types of UVC light can damage your skin or eyes.
  • The types of UVC light lamps sold for at-home use are often lower in intensity. That means it may take a longer time to kill germs.
  • UVC light lamps can potentially contain mercury or produce ozone, both of which can be harmful to humans.
  • It’s possible that prolonged exposure to UVC light can cause materials like textiles, plastics, or polymers to degrade.

Far-UVC light may be a potentially safer option for disinfection. Research has indicated that, unlike other types of UVC light, it doesn’t appear to penetrate the outer layers of the skin or eye. However, further safety studies are needed.

You may have heard about some methods to kill the new coronavirus using UV light or high temperatures.

Let’s take a closer look at some popular myths and why they could be potentially dangerous, as well as the safest known ways to prevent COVID-19.

Myth #1: Sun exposure can protect you from COVID-19

While sunlight does contain UV light, it’s mostly UVA and UVB light. These types of UV light are less effective at killing SARS-CoV-2.

Perhaps more importantly, prolonged exposure can also lead to skin damage, sunburn, or even skin cancer.

Myth #2: Using a UV lamp on your body can protect you from COVID-19

While a UV lamp may be used to disinfect surfaces, avoid using one to kill the new coronavirus on your hands or other parts of your body.

Remember, most types of UV light can be harmful to people. Exposure can result in skin irritation, damage, or burns.

Myth #3: Sitting in a hot bath can prevent COVID-19

This method won’t prevent you from becoming ill with COVID-19. In fact, your body temperature will remain pretty much the same in a hot bath.

Additionally, sitting in a very hot bath can actually harm you by causing burning or scalding.

Myth #4: The hot air from a hand dryer can kill the virus on your hands

While the air emitted from a hand dryer is warm, it won’t kill SARS-CoV-2 on your hands.

The best way to eliminate the virus from your hands is by thoroughly washing your hands with soap and water or using an alcohol-based hand sanitizer.

Fact: There are several safe ways to prevent getting COVID-19

To prevent becoming ill with COVID-19, take the following steps:

The type of UV light that’s most effective at killing germs, like viruses and bacteria, is UVC light.

UVC light can effectively kill SARS-CoV-2, the new coronavirus that causes COVID-19. Much of the research on this topic focuses on far-UVC light. This is a type of UVC light that still kills germs but is less harmful to humans.

UVC light is mainly used for disinfection in healthcare settings. While you can buy a UVC light lamp for your home, remember that these lamps are often lower in intensity.

Also, the optimal length of exposure, wavelength, and dose of UVC light needed for killing the new coronavirus is yet to be determined.