Although there are many popular science articles about UV disinfection, there are still many people who wondering whether this can really kill the virus. Today, we will talk about this from the principle of ultraviolet disinfection, hope to let you understand the inactivation process of the COVID-19, and no longer worry or worry after UV disinfection.
First, let us understand the structure of the coronavirus.
The COVID-19 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, he budding release of nascent viruses, and the formation of viral envelopes.
If ultraviolet light or other disinfectants 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.
Ultraviolet rays generally refer to short waves with a wavelength of 100 to 280 nanometers. It should be pointed out that since the wavelength below 200nm is vacuum ultraviolet, it can be absorbed by air. Therefore, the wavelength of UVC that can penetrate the atmosphere is between 200 ~ 280nm, which is also the band of choice for UV lamp products on the market. Among them, the sterilization effect at 253.7nm is the strongest.
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. Purchase a UV lamp with 253.7nm wavelength for disinfection and sterilization(the strongest effect).
2. 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. Doors and windows should be closed when disinfecting the room, and personnel should be avoided. The irradiation time should not be less than half an hour. After disinfection, it should be fully ventilated.
4. 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.
5. Ultraviolet rays can damage the skin and cornea, so do not directly touch or stare at the human body, especially for children.