Far-UVC 222 nm kills more than 99.9% of seasonal coronaviruses in air droplets.

Far-UVC It is a part of UVC, and the wavelength range is 207 nanometers to 222 nanometers. It sterilizes objects and the air by penetrating the genetic material of microorganisms and breaking their bonds, preventing them from replicating. However, it cannot penetrate the tear layer of the eye or the dead cell layer around the skin and does not reach or damage living cells in the body, so it does not cause skin cancer or cataracts. Simply put, it is safe for humans but kills bacteria.

Researchers have shown that far-UVC light in the C-band can safely kill airborne influenza viruses, using a spray device to aerosolize two common coronaviruses. Then, the coronavirus contained in the aerosol flows in the air in front of a C-band far-ultraviolet lamp. After the aerosols were exposed to far-UVC light in the C-band, the researchers ran tests to see how much of the virus was still alive.

The researchers found that more than 99.9 percent of the exposed virus was killed by very low doses of C-band far-UVC light. Based on these findings, the researchers estimate that sustained exposure to far UV light within current regulatory limits will kill 90% of airborne viruses in about 8 minutes, 95% in about 11 minutes, and kill in about 16 minutes. 99%, kills 99.9% in about 25 minutes.

The sensitivity of the coronavirus to far-ultraviolet rays suggests that it is feasible and safe to use overhead far-ultraviolet lamps in indoor public places with people to reduce the risk of human-to-human transmission of coronavirus and other viruses such as influenza.

Far-UVC does not distinguish between types of coronaviruses, so we expect it to kill novel coronaviruses in the same way. Because the novel coronavirus is mainly transmitted through airborne droplets and aerosols formed by coughing and sneezing, it is important to have a tool that can safely inactivate the coronavirus in the air, especially if there are people nearby. Because it can be used safely in occupied spaces such as hospitals, buses, planes, trains, train stations, schools, restaurants, offices, theaters, gyms, and any indoor place where people can gather, C-band far-UVC can be used in conjunction with other measures, Such as wearing a mask or washing your hands to limit the spread of the new coronavirus and other viruses.

According to the wavelength division in the electromagnetic spectrum: Ultraviolet (Ultraviolet) refers to the general term for radiation in the electromagnetic spectrum with wavelengths ranging from (10 nanometers to 400 nanometers), with wavelengths between visible light and X-rays, invisible to the naked eye.

Ultraviolet rays can be divided into four areas according to different wavelengths: long-wave ultraviolet abbreviated as UVA, with wavelengths 320-400 nm; medium-wave ultraviolet abbreviated as UVB, with wavelengths of 280-320 nm; short-wave ultraviolet abbreviated as UVC, with wavelengths of 200-280 nm; vacuum Ultraviolet light is referred to as UVD, and the wavelength of the wavelength is 100 nanometers to 200 nanometers.

Among them, long-wave ultraviolet (UVA) penetrates clothing and human skin much stronger than medium-wave ultraviolet, can reach the depths of the dermis, and can act on the melanin in the epidermis, thereby causing skin melanosis and darkening the skin. Therefore, it is also called "long-wave dark spot effect ultraviolet light".

The vast majority of UVB rays are absorbed by the epidermis of the skin and cannot penetrate into the skin. However, due to its high energy, it can cause strong photodamage to the skin. The dermal blood vessels in the irradiated area will expand, and the skin may appear red, and swollen, with blisters, and other symptoms.

Short-wave ultraviolet (UVC) has a disinfection and sterilization effect, also known as "C-band ultraviolet" or "short-wave sterilization ultraviolet". It has the weakest penetrating ability and cannot penetrate the most transparent glass and plastics. The short-wave ultraviolet rays contained in sunlight are almost completely absorbed by the ozone layer. Short-wave ultraviolet rays are very harmful to the human body. Short-term exposure can burn the skin. Long-term or high-intensity exposure can also cause skin cancer or cataracts and other diseases.

Ultraviolet germicidal lamps emit UVC. Conventional short-wave sterilizing UV light (wavelength 254 nanometers) can be used to sterilize unoccupied spaces such as empty hospital rooms or empty subway cars. However, direct exposure to these conventional UV lamps is not an option in occupied spaces, as this may be harmful to health.