The use of UV lightsfor home disinfection not only uses high energy UV light to interrupt the structure of viral RNA and deprive it of the ability to reproduce and self-replicate, but also produces ozone during the germicidal process, which itself gradually destroys the structure of viruses from the outside in, so this can be considered a “double germicidal” process.
Amongst the many means of disinfection, UV lampsare one of the lesser encountered in our lives. So, does disinfecting your home with UV light work or not? What exactly should you be aware of when using UV lamps? Let’s have a good chat about it.
The first thing to know is that disinfection with UV lamps is effective for COVID-19. Back in the SARS era, experts at the CDC Institute of Viral Disease Prevention and Control found that 30 minutes of UV light at an intensity of more than 90 μW/cm² was effective in killing the SARS virus. And it is clearly stated in the “Treatment Protocol for Pneumonia with COVID-19 Infection” (Trial Version 5) that COVID-19 is sensitive to UV light. Recent studies have even found Delta variant can be effectively inactivated as long as UV light can be used scientifically and reasonably.
Let’s dive right in now, and you can click on the question that interest you,
1 Delta Variants: What We Know About Scientific Principles?
Delta variant causes more infections and spreads faster than earlier forms of SARS-CoV-2 (COVID-19 pathogenic virus)
The B.1.617.2 (Delta variant) of the B.1.617 spectrum is commonly known as the “Indian variant” because it was first discovered in India.
On May 31, 2021, the World Health Organization (WHO) named several major variant strains of COVID-19 with Greek letters to avoid the stigmatization problem caused by place names, including B.1.617.1 as “Kapha” and B.1.617.2 as “Delta”. Delta”, WHO said that this naming does not replace the scientific name.
The Centers for Disease Control and Prevention (CDC) in the United States concluded that delta-mutated strains have a basic infectious number R0 value (number of infections per infected person) of 8 to 9 and are more likely to cause severe disease. In contrast, the unmuted new coronavirus strain is infectious in two to three persons. The Delta variant virus is 40-60% more infectious than the Alpha variant, and the Control Center recommends that vaccinated individuals should continue to wear masks indoors.
On June 18, 2021, the World Health Organization stated that Delta has increased in infectivity, spread to 92 countries, and has become the dominant strain of COVID-19 worldwide. According to the Public Health England report in August, the cumulative case fatality rate of the Delta variant was 0.3% (0.21% if only unvaccinated), compared with 1.1% for the old Alpha variant during the same period.
2 Do UV Lights Kill Delta Variant Or Not?
1) What is the principle of UV lamp disinfection?
Simply put, it is the use of high-energy UV light to interrupt the structure of the viral DNA, so that it loses the ability to reproduce and self-replicate, thus achieving the goal of sterilization. The process of disinfection by UV lamps also produces ozone, which itself gradually destroys the structure of viruses from the outside in, thus achieving a sterilizing effect. The use of UVC lamps for disinfection of the home can therefore be considered a “double sterilization”.
When using UV lamps, attention should also be paid to the irradiation distance, i.e. the distance from the lamp to the object to be illuminated. Generally speaking, the appropriate distance for UV lamps is between 1-2 meters, so when using them, it is best to place them in the center of the space. As the disinfection feature of the UV lamp is coverage, i.e. the area covered by the light will be disinfected, so when using it, try to reduce the light coverage, some items (such as quilts) can be spread out for disinfection.
3)How to choose a suitable UV lamp?
When using a 254nm disinfection lamp, ensure that no one is in the room and that the windows are open after use. 254nm UV lamps have a good disinfection effect but can cause damage to the human body if used improperly. Therefore, when using the lamp, the first thing to do is to ensure that no one is in the room and that the windows and doors are closed. After irradiating the lamp for a sufficient period of time (depending on the intensity of the UV lamp used, please refer to the product instruction manual), open the windows and ventilate the room for a period of time before anyone enters. The reason for this is that 254nm UV lamps produce ozone during use, and high concentrations of ozone can cause dizziness, nausea, and other symptoms, and can even lead to respiratory problems. Long-term use of UV lamps can be harmful to the eyes, inducing conjunctival and corneal diseases, and in some cases, even affecting vision. In addition, long-term exposure to the skin can cause redness, swelling, and itching in milder cases, or even skin cancer in the more serious ones. It has been experimentally proven that 222nm UV lamps are harmless to humans and have a good disinfection effect. Therefore it is recommended to use 222nm lamps in crowded places such as schools, supermarkets, hospitals, etc.
In general, the use of UV lamps to eliminate the new coronavirus is still effective, but it should be noted that the role of UV lamps is limited, not only has a small irradiation range and cover the limitations of the use of irradiation, and the use of 254nm UV lamps improperly will also cause damage to the human body, so we need to be extra cautious when using. So when UV disinfection is required when crowds gather, it is recommended that 222nm UV lamps are used to ensure people’s safety while fully disinfecting.