Sunlight contains three types of UV. First there is UVA, which makes up the vast majority of the ultraviolet radiation reaching the Earth's surface. It's capable of penetrating deep into the skin and is thought to be responsible for up to 80% of skin ageing, from wrinkles to age spots.
Next there's UVB, which can damage the DNA in our skin, leading to sunburn and eventually skin cancer (recently scientists have discovered that UVA can also do this). Both are reasonably well known, and can be blocked out by most good sun creams.
There is also a third type: UVC. This relatively obscure part of the spectrum consists of a shorter, more energetic wavelength of light. It is particularly good at destroying genetic material – whether in humans or viral particles. Luckily, most of us are unlikely to have ever encountered any. That's because it's filtered out by ozone in the atmosphere long before it reaches our fragile skin.
The study, carried out by researchers at Columbia University Irving Medical Center, has used far-ultraviolet C (UVC) light, at a wavelength which is safe for humans, to kill more than 99.9% of corona viruses that are found present in airborne droplets. The corona viruses are structurally similar to the SARS-CoV-2 virus that causes the novel COVID-19.
Currently, the viruses can be killed by conventional germicidal UVC light at a wavelength of 254 nm wavelength, however, this wavelength is not safe for humans. For this study, the researchers looked at using far-UVC light at a wavelength of 222 nm, which cannot penetrate through the eye or the outer, dead layer of skin – meaning it cannot damage human cells. The researchers believe that far-UVC light will be safe to use in occupied indoor public places to reduce the risk of transmission and infection of COVID-19.
The researchers believe that continuous exposure to the far-UVC light would kill 90% of airborne viruses in about eight minutes, 95% in 11 minutes, 99% in about 16 minutes, and 99.9% in 25 minutes.
A far-UVC light is believed to be safe to use in occupied spaces like hospitals, buses, planes, trains, train stations, schools, restaurants, offices, theatres, gyms, and anywhere that people gather indoors. HortiBest now has applied far-UVC to our existing models which could help with indoor viruses killing.
And also, always keep in mind that DON'T get yourself direct exposure to any UVC light.