Are ultraviolet light (UV-C) useful against coronavirus disinfection?
Q: Can UVC lamps inactivate the SARS-CoV-2 coronavirus?
A: UVC radiation is a known disinfectant for air, water, and nonporous surfaces. UVC radiation has effectively been used for decades to reduce the spread of bacteria, such as tuberculosis. For this reason, UVC lamps are often called "germicidal" lamps.
UVC radiation has been shown to destroy the outer protein coating of the SARS-Coronavirus, which is a different virus from the current SARS-CoV-2 virus. The destruction ultimately leads to inactivation of the virus. UVC radiation may also be effective in inactivating the SARS-CoV-2 virus, which is the virus that causes the Coronavirus Disease 2019 (COVID-19). However, currently there is limited published data about the wavelength, dose, and duration of UVC radiation required to inactivate the SARS-CoV-2 virus.
In addition to understanding whether UVC radiation is effective at inactivating a particular virus, there are also limitations to how effective UVC radiation can be at inactivating viruses, generally.
Direct exposure: UVC radiation can only inactivate a virus if the virus is directly exposed to the radiation. Therefore, the inactivation of viruses on surfaces may not be effective due to blocking of the UV radiation by soil, such as dust, or other contaminants such as bodily fluids.
Dose and duration: Many of the UVC lamps sold for home use are of low dose, so it may take longer exposure to a given surface area to potentially provide effective inactivation of a bacteria or virus.
UVC radiation is commonly used inside air ducts to disinfect the air. This is the safest way to employ UVC radiation because direct UVC exposure to human skin or eyes may cause injuries, and installation of UVC within an air duct is less likely to cause exposure to skin and eyes.
There have been reports of skin and eye burns resulting from improper installation of UVC lamps in rooms that humans can occupy.
Q: Can UVB or UVA radiation inactivate the SARS-CoV-2 coronavirus?
A: UVB and UVA radiation is expected to be less effective than UVC radiation at inactivating the SARS-CoV-2 coronavirus.
UVB: There is some evidence that UVB radiation is effective at inactivating other SARS viruses (not SARS-CoV-2). However, it is less effective than UVC at doing so and is more hazardous to humans than UVC radiation because UVB radiation can penetrate deeper into the skin and eye. UVB is known to cause DNA damage and is a risk factor in developing skin cancer and cataracts.
UVA: UVA radiation is less hazardous than UVB radiation but is also significantly (approximately 1000 times) less effective than either UVB or UVC radiation at inactivating other SARS viruses. UVA is also implicated in skin aging and risk of skin cancer.
Q: Is it safe to use a UVC lamp for disinfection purposes at home?
A: Consider both the risks of UVC lamps to people and objects and the risk of incomplete inactivation of virus.
Risks: UVC lamps used for disinfection purposes may pose potential health and safety risks depending on the UVC wavelength, dose, and duration of radiation exposure. The risk may increase if the unit is not installed properly or used by untrained individuals.
Direct exposure of skin and eyes to UVC radiation from some UVC lamps may cause painful eye injury and burn-like skin reactions. Never look directly at a UVC lamp source, even briefly.
Some UVC lamps generate ozone. Ozone inhalation can be irritating to the airway.
UVC can degrade certain materials, such as plastic, polymers, and dyed textile.
Some UVC lamps contain mercury. Because mercury is toxic even in small amounts, extreme caution is needed in cleaning a lamp that has broken and in disposing of the lamp.
Effectiveness: The effectiveness of UVC lamps in inactivating the SARS-CoV-2 virus is unknown because there is limited published data about the wavelength, dose, and duration of UVC radiation required to inactivate the SARS-CoV-2 virus. It is important to recognize that, generally, UVC cannot inactivate a virus or bacterium if it is not directly exposed to UVC. In other words, the virus or bacterium will not be inactivated if it is covered by dust or soil, embedded in porous surface or on the underside of a surface.
In order to combat COVID-19, Eagle Star Lighting recently developed a new and smart device of UV-C Disinfectant Trolley. This device has to lead the charge in killing and destroying pathogens that exist in rooms and on hard surfaces. Now you can use one of the most powerful UV-C lamps to sanitize and disinfect rooms and surfaces with the security of knowing that the new addition motion sensor will act to protect you.
The device acts as a "disinfectant robot", controlled by the included remote control, or can be fully operated by its motion sensors. The UVC Disinfectant Trolley can work diligently while the room is empty, but once it detects an individual walking in, it can shut off or “pause” the disinfecting process and re-start again once they leave, allowing for the disinfecting process to continue while people go about their daily business. It is suitable for use in a range of areas: hospitals, schools, restaurants, offices, homes, clinics, entertainment centers, and food manufacturers, etc. These powerful UV-C rays target micro-organisms that cause problems for everyone.