Can UV disinfection really inactivate the coronavirus?

Although there are many popular science articles about UV disinfection, there are still many people who wonder whether this can really kill the virus and bacteria. Today, we will talk about this from the working principle of ultraviolet disinfection, hope to let you understand the inactivation process of the COVID-19, and no longer worry after UV disinfection.

In this article, we will talk about how does UV light inactivates the new coronavirus, how to use UVC light to kill the new coronavirus, and some things you need to know to prevent the COVID-19.

First, let us understand the structure of the new coronavirus.

The COVID-19 is caused by SARS-CoV-2, which is an enveloped virus. In addition to the capsid formed by the protein and the genetic material (single-stranded RNA) wrapped around it, it also has an envelope.

On the surface of the envelope structure, there are three layers of glycoproteins, there are:

S: Spike protein  

It is the receptor-binding site, cytolysis, and the main antigenic site.

E: Envelope protein  

It is relatively small and is a protein bound to the envelope.

M: Membrane protein 

It is responsible for the transportation of nutrients across the membrane, the budding release of nascent viruses, and the formation of viral envelopes.

If UV light or other sterilizers can destroy the structure of the new coronavirus, it should be able to effectively inactivate it.

The inactivation of protein is mainly through heating, dehydration, oxidation, salt formation, deamination, change of charge and other methods to change and destroy its secondary or tertiary structure. At present, disinfection products on the market are classified according to the site of action, which can be summarized into the following two categories:

Acting directly on the internal genetic material nucleic acid: UV disinfection

Acts on protein to inactivate: most chemical disinfectants, high-temperature disinfection

The ultraviolet disinfection mechanism directly destroys the viral RNA: UV lamps, UV disinfection cabinets.

Then let's see what wavelength is the most effective.

According to different wavelengths, Ultraviolet rays can generally be divided into UV-A, UV-B, and UV-C. When inactivating SARS-CoV-2 coronavirus, UVA and UVB are not as effective as UVC. 

UV-A: Most of the ultraviolet rays that can be irradiated on the earth are UVA. In the perspective of disinfection, UVA is far less effective than UVC in inactivating other SARS viruses. And it will penetrate the skin layer and cause skin aging and increase the risk of skin cancer.

UV-B: UVB can inactivate other SARS viruses, but there is currently no evidence shows that it can inactivate SARS-CoV-2. In terms of disinfection, UVB is not as effective as UVC.

Due to UVA and UVB cannot be used for inactivating the SARS-CoV-2, the UV sterilizer devices used to prevent the COVID-19 are almost in deep UVC wavelength.

After UVC is irradiated with the new coronavirus, it can photochemically react with its genetic material RNA, causing the rupture of phosphodiester bonds and hydrogen bonds to form pyrimidine dimers (such as the formation of uracil cyclobutane dimers, uracil hydrates), Cytosine hydrate, etc.), causing the virus to lose its ability to replicate.

1. The wavelength also affects the effects of UVC light sterilization. Deep UVC has better disinfection performance. Suntech has 275nm, 265nm and 255nm UVC LED products for you to choose.

2. The SARS-CoV-2 can be inactivated only when the UVC directly irradiates the virus for a certain period of time. The penetration of ultraviolet rays is poor, so it should be directly irradiated on the surface of the object during sterilization and the distance from the irradiated object should not exceed 1 meter.

3. Indoor air disinfection, the amount of ultraviolet disinfection is ≥1.5W/m³, the effective range of surface disinfection is within 1m around the lamp, and the disinfection time is ≥30min. When the temperature is lower than 20°C or higher than 40°C, and the relative humidity is greater than 60%, the irradiation time can be appropriately extended.

4. Ultraviolet rays can damage the skin and cornea, so do not directly touch or stare at the human body, especially for children. If the skin and eyes are directly exposed to UVC radiation, it may cause eye pain and skin reactions similar to burns.

5. The researches show that 222nm is safe for human skin and eyes. Due to the limitations of technological development, there is currently no 222nm LED product. If you need the far UVC product for body disinfection, maybe the 222nm excimer lamp can meet your demands.

1. Can exposure to sunlight prevent COVID-19?

As we mentioned before, the sunlight mainly includes UV-A and UV-B light, the UV-C cannot pass through the ozone layer to reach the earth. So exposure to sunlight can not help you to be protected from the COOVID-19. In addition, prolonged exposure to the sun can also cause skin sunburn and even increase the risk of skin cancer.

2. Can irradiating the body with UVC rays sterilize and prevent the COVID-19?

Most UVC lamps cannot be used for human body sterilization. UVC light sterilizers can only be used for item surface sterilizing and air purification. Please do not expose your skin directly to UVC light, nor look directly at UVC light.

3. Can the hand dryer inactivate the virus in my hands?

Although the dryer emits hot air, it cannot inactivate the virus. To sterilize your hands, the best way is to wash your hands thoroughly with a special disinfectant.

Here are some tips to help you prevent COVID-19:

1. Keep a distance from others, at least 6 feet.

2. Reduce your time out and wear a mask when you go out.

3. Use a UVC disinfection lamp to sterilize the air in the public environment and sterilize the surface of the objects.

4. Use a special cleaning and disinfectant to disinfect the exposed skin.

The end

To prevent COVID-19 and inactivate SARS-CoV-2, the UVC sterilizer is the most effective, and far UVC is safe to human skin irradiation.