UVC sterilisers
Ultraviolet-C (UVC) radiation has wavelengths of 100nm - 280nm and is in the spectrum of the sun’s radiation that we are rarely exposed to, as the ozone layer in the stratosphere prevents UVC rays from reaching the surface of the earth.
Ultraviolet Germicidal Irradiation (UVGI) is a disinfection method that uses UVC. This method of disinfection has been applied in the disinfection of surfaces and sanitisation of drinking water. UVC sterilisers which use UVGI have been applied in the healthcare sector and in research. The efficacy of UVGI against a range of microbes has been demonstrated in numerous studies. 1-2
Challenges in using UVGI
UV disinfection has a short turn-around time (less than 30 min) and does not leave any chemical residues behind after treatment. However, the following factors must be considered when it is applied, whether as a fixed installation or as a portable system:
- There must be line of sight from the UVC source to the surface to be disinfected for treatment to be effective. High-touch points that are obscured may be missed. For example, surfaces of door handles, handle bars, or toilet flushes that are not directly in the line-of-sight will not be disinfected.
- The effectiveness of UVGI in inactivating microorganisms depends on the duration of exposure, intensity, distance of surface from source and wavelength of the UV radiation. There is therefore a need for careful calibration and monitoring.
Is UVC safe?
UVC poses potential health risks such as eye injury (e.g. irritation and inflammation of cornea) and skin injury (e.g. erythema). The World Health Organisation (WHO) has advised that UV sterilisers should not be used to disinfect the hands or any areas of the skin.3
Chronic exposure to UV radiation can also accelerate the skin aging process and increase the risk of skin cancer. Care must be taken to ensure that the irradiated space is not occupied during UVGI, and measures must be in place to prevent accidental exposure. 4-5
UV products are to be kept out of reach of children.
Advisory
As UVC radiation can cause eye injury (e.g. irritation and inflammation of cornea) and skin injury (e.g. erythema), NEA does not recommend the household use of such products. Other alternative disinfection methods are available. Please refer to NEA’s list of active ingredients and household disinfectant and cleaning products for disinfection of the COVID-19 virus.
For reference please visit: https://www.nea.gov.sg/our-services/radiation-safety/advisory-on-the-use-of-uvc-sterilisers-in-the-home
