How Does UV Sterilization Work?


The term UV simply denotes ‘Ultraviolet’ which means “beyond violet”. It refers to a range of electromagnetic waves with a higher frequency and energy. For UV sterilization, only UVC (100-280nm) has high enough power to kill microorganisms effectively.

UV is divided into three types with reducing wavelengths and increasing energy. They are UVA, UVB, and UVC. UVB and UVA are not advisable means of sterilization because they both cause harm to the body. UBA, also known as show-wave light, affects the skin’s top layer, causes skin cancer and sunburns. It tends to damage the skin layers and is highly linked with cancer. It also damages the skin’s DNA.

UVA is not left out of this. It is also known as longwave light and accounts for 95% of the UV radiation that reaches the earth. UVA penetrates the skin second layer and plays a significant part in skin damage and wrinkling. It also penetrates glass and clouds.

How effective is UV sterilization?

UV sterilization is not a new technology, having been discovered in 1879, but becoming more pronounced in the 20th century.

UV sterilization, also is known as UV disinfection or Ultraviolet Germicidal Irradiation (UVGI), is quite useful. It works by breaking down individual chemical bonds and the structure of DNA, RNA, and proteins, causing a microorganism to be unable to increase. When an organism is unable to grow, it is considered dead since it is unable to reproduce within a host and is no longer infectious.

UV sterilization uses the frequency of UVC to destroy biomolecules. Thus, its effectiveness depends on the total frequency and energy applied, which is affected by the length of exposure time and the distance from light source.

For example, if you use a UV lamp held within 2 inches above a petri dish grown with B. coli, it will only take 1-2 min to show complete sterilization. While sterilizing surgical instruments in a medium UV box, it might take 10-15 min. For cleaning a 6-foot biosafety cabinet in a lab, a standard recommendation is 30 min.

Does it work for bacteria and viruses?

Recent studies have shown that UV sterilization does work for bacteria and viruses. It is efficient against all foodborne pathogens, natural microbiota, and even yeasts. Although killing these microorganisms varies because they come with different sizes and shapes, which affect their UV absorption.

UV is unique in its way in the sense that it provides rapid inactivation of microorganisms through a physical process. For instance, when organisms such as bacteria, viruses, and protozoa are visible to the germicidal wavelengths of UV light, they are rendered dead because, at this point, they become incapable of reproducing and infecting.

In recent studies, it has also been observed that through a process called UV-Oxidation, the UV light can destroy chemical substances such as pesticides and industrial solvents.

These microorganisms are rendered dormant by UV light as a result of damage to nucleic acids. Thus, the high frequency associated with short wavelength UV energy, primarily at 254 nm, is absorbed by cellular RNA and DNA, causing the UV energy to form new bonds between distant nucleotides, creating double bonds.

Can UVC help prevent the spread of the coronavirus?

Based on existing evidence, it is believed that UVC can help prevent the transmission of the Corona Virus. This is because as a piece of equipment used for disinfecting the surrounding, this technology has been able to kill microorganisms which even the eye cannot see. Therefore, when objects that are used frequently are placed under this light, the microbes are destroyed.

Where UV can be used?

Using UV sterilization is a handy measure for disinfecting microorganisms.

It can disinfect the air in confined spaces, such as the hospital setting through UV devices like lamps and lights placed at the top of rooms and other areas of circulation. This improves both the air quality and the effectiveness of the UV sterilization.

UV can also disinfect equipment in workspaces without leaving residue. This makes it a more efficient solution for ensuring that equipment and instruments are adequately cleaned.

However, because UV sterilization is used for a wide range of things, that does not necessarily make it invincible. There are certain limitations to this UV sterilization.

Limitations of UV Sterilization

One noticeable feature of the UVC lamp is its protective shields, which help to avoid direct contact between the device and humans. This is because UVC is dangerous to humans, especially the skin and eyes.

It has also been observed that UVC causes damage in both DNA/RNA and surface proteins that they cannot be used as vaccines to trigger proper immune responses.

It only works if the object to be sterilized is directly under the light. If the object is not in line with the UV light, it will not be sanitized.  For example, in treating high clarity, purified distilled water, the UV light must be placed directly above it. If the UV light is not set appropriately, it causes particles to be suspended. The microorganisms buried within these particles are shielded from the UV light and passes through the unit unaffected.

Advantages of UV sterilization

It is easy to use, and chemicals are not needed. Therefore, no chemical residue will be left.

It can kill all kinds of drug-resistant bacteria and microorganisms as long as it is placed appropriately.

UV treatment is non-corrosive. Therefore, it does not affect the quality of the water.

It is effective against Cryptosporidium and Giardia, which are chlorine resistant pathogens.

Whether you are looking for a UV light toothbrush sterilizer, a sanitizer or a wand to wave over microorganisms on hotel sheets, or a gizmo to disinfect your smelly shoes, UV sterilization is a great option.


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