The recent pandemic increased public interest in the use of UVC irradiance for killing/inactivating microorganisms on surfaces. These applications range from whole-room disinfectors to small appliance-type units. However, testing standards are yet to be developed for surface treatment applications.
The application of disinfection of surfaces with UV light is used in the food industry for different purposes. When it comes to surface disinfection we pay special attention to the use of proper kinetic data of microbial inactivation obtained from test coupons of the treated surface materials in contrast to that obtained in suspension of aqueous media or air. These data are of limited use in predicting the surface disinfection rate. Since complex interactions may occur between microorganisms and surface materials, such as shielding effects from incident UV, the efficacy of UV light depends on surface structure or topography. Efficacy is maximum when there is direct exposure to the UV light. 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. In addition, the use of a powerful enough UV lamp assures appropriate dose delivery.
However, it is important that depending on the wavelength, dose and duration of exposure UVC disinfection purpose lamps are associated with different risks and must only be installed by trained professional technicians.
UVC lamps are not to be used for skin disinfection and direct exposure of skin and eyes. UVC radiation from some UVC lamps may cause painful eye injury and burn-like skin reactions.
Ozone can be generated by some UVC radiation and airway irritation can result if inhaled
Certain materials, such as plastic, polymers, and dyed textile degrade if exposed to UVC radiation.
Finally, special attention should be taken during cleaning of broken UVC lamps since they contain mercury (Hg), which is toxic even in small amounts.