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Can UVC light kill the viruses and bacteria?

Time: 2020-04-21

For decades, scientists have been devoted to the research of UVC light for disinfection, especially when the UVC market is huge and the human pursuit of health is more important than ever before. 


More and more reports indicate that UVC light products can kill viruses and bacteria higher than a 99.9% rate, which directly leads to the crazy purchase of UVC products.

 

But in fact, few people know exactly what UVC light is and whether UVC light is useful for sterilization.

 

Next, we'll explain in detail what UVC lights are, how they work, their precautions for use and some commercial applications to help you gain a clear understanding.


uvc light sterilization


Wha is UVC light?


As we all know, Sunlight is a mixture of light energy at different wavelengths.


The wavelengths range from 380 nanometers (nm) to 780 nanometers (nm) are called visible light, while those beyond the range of wavelength are called invisible light.

 

Ultraviolet light is a type of invisible light ranging from 10 nm to 400 nm. And the function of UV light depends on the range of wavelength.

 

  • UV-A: 320nm to 400 nm

 

It makes up the majority of UV light reaching the Earth. And it can damage our skin.

 

  • UV-B: 280nm to 320nm

 

It can treat skin diseases. But too much exposure will cause sunburn and even skin cancer. And only less than 2% of UVB can reach the earth.

 

  • UV-C: 200nm to 280nm

 

It is particularly good at sterilizing. But its penetration ability is very weak. Before reaching the ground, all UVC light will be absorbed by ozone in the atmosphere. That means, standing under the sun is useless for sterilization.

 

  • In summary: UV light Rule

 

The shorter the wavelength, the stronger the energy, but the weaker the penetration, the faster the disappearance.


Function of UVC light

 

Related Knowledge: Which UV light is the best?

 

Because UVC light can be used for sterilization, coupled with the epidemic environment, the market demand for UVC products can be described as Crazy now.

 

And the market valuation even increased from 140,000,000 US dollars to an estimated 500,000,000 US dollars.

 

The big question right now may be how does UVC light  work and can it kill viruses & bacteria?


How does UVC light work?


Before the deep study of UVC light, I thought all sunlights have the sterilization effect. Bacteria and viruses will be killed by "sunburn" or heat.

 

But that's not the truth. 


  • Sterilization Principle of UVC light


In fact, UVC light will destroy the DNA or RNA of the bacteria & viruses, without the use of chemicals, making them inactive and unable to reproduce.

 

Since the lifespan of single bacteria & viruses is very short, once they lose the reproduce ability, it means death. So the purpose of sterilization has been achieved.


In scientific research, it has been found that UVC light can use very little time to finish the disinfection process and make most microbes reduction up to 99.99%.


Research of UVC light

 

Based on this information, UVC light is believed to be quiet effective at killing viruses and bacteria.


However, the vitality of different viruses and bacteria are different. Some bacteria&viruses may be injured once they are exposed to UVC light, while others are not.


If the UV dose is insufficient, some viruses will only temporarily lose activity, and then slowly repair their own structure.


  • Special requirements of UVC lights

 

At present, there are no specific figures to show how much UV dose flu viruses needs to be killed. Maybe 1,085 mJ / cm2 or 3,640 mJ / cm2 . Anyway, a huge number. 

 

You may be wondering if we stand under the sunlight containing UVC light, can we be disinfected by it?

 

Unfortunately, the answer is no. Although the sterilization ability of UVC light is extremely strong, the penetration ability to objects (including air) is extremely weak. Before reaching the ground, all UVC light will be filtered out by ozone in the atmosphere.

 

This is why we need to use a carrier similar to ultraviolet disinfection lamps to achieve disinfection.


Please pay attention to the fact that most UV lamps on the market are only designed to meet the common standard, that is, 40mJ / cm2 UV dose required for a 99.99% inactivation rate.


Study result of UVC light

 

Further considering the decay of UVC light in the air, those lamps make no sense for disinfection.

 

So don't easily believe some company's saying "we can kill the viruses & bacteria", sometimes it's only the marketing language.

 

We have to realize that only the efficiency, time and cost are the key factors in our choice of UV lamps.


Are ultraviolet lamps containing uvc light safe?


Although UVC light can indeed kill viruses and bacteria, there are various problems with household ultraviolet disinfection lamps on the market:

 

(1) Traditional ultraviolet disinfection lamps are big (at least 40cm height or above), low efficiency. 1W LED light source can basically cover only 1 square meter of space.


(2) The light source of most ultraviolet disinfection lamps contains mercury, which is bad to the environment and health if released.

 

(3) Most ultraviolet disinfection lamps are broad-spectrum lamps including UVC, UVA, and UVB, which are likely to produce ozone, leading to symptoms such as fatigue, cough, chest tightness, nausea, and memory loss. 


Applications of UVC light

 

From this perspective, the main application scenarios of UVC light should be industrial types to maintain safe.


Applications of uvc light


To make better use of UVC light, we have developed a new lighting technology, which can make the UVC energy in a very small size with 3.5mm x 3.5mm without mercury. 


With this size, it can apply in many portable equipment with disinfection functions:

 

(1) Surface


Contaminated surfaces such as hospital rooms and equipment, living rooms, airports, and almost all public places or private items. 


(2) Water


Mercury-free UVC light is a clean and safe water disinfectant, UVC LED based solutions tackle these pathogens without impacting the water's smell, taste or mineral contents.

 

We can use UVC solutions in the water purification system or the toilet system. 


(3) Air


Air purifiers remove 99.97% of airborne particles, however, the filters do not remove small pathogenic micro-organisms, like influenza.

 

We can use UVC solutions in the air purification system or the commercial air conditioning duct system. 


How to use UVC light

 

All in all, UVC light can indeed kill viruses and bacterial if we choose the right system for specific applications.


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