Abstract

UVC radiation is able to kill or inactivate pathogenic microorganisms and viruses. With a wavelength of 254 nm, it has therefore been used for decades in enclosed systems or with shielded radiation sources to disinfect water, room air or solid surfaces. This radiation can cause both acute and long-term damage to the eyes and skin of humans. Appropriate precautions have therefore been taken to avoid unintentional exposure of people.

In an occupational context, if exposure cannot be ruled out, exposure limits based on the recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) must be met. Individually adapted protective measures are also provided for employees if they belong to vulnerable groups that are particularly sensitive to UV radiation. Compliance with the exposure limits alone is not always sufficient for these employees.

The use of so-called far-UVC radiation for disinfection by unshielded, open radiation sources in the presence of people, e.g. in public spaces, has been discussed for several years. Far-UVC radiation covers the spectral range from 200 nm to 240 nm; the wavelength of 222 nm is usually used.

Due to the very low penetration depth of far-UVC radiation into the eye and skin in contrast to UVC radiation at 254 nm, it is often argued that no acute or long-term health consequences for humans are to be expected. Potentially vulnerable groups have not yet been considered in the discussion. These include children, older people with thinner skin or people with skin and eye diseases. It is currently being discussed at international level to relax the UVC exposure limits.

Against this background, the Commission on Radiological Protection (Strahlenschutzkommission – SSK) was commissioned to comment on the risks of using far-UVC radiation for disinfection in the presence of people, also taking into account vulnerable groups.

In view of the potentially harmful photobiological effects of UVC radiation, the SSK considers the current data situation to be insufficient to rule out health risks to the population from the use of far-UVC radiation (for disinfection in the presence of people in public spaces).

The SSK therefore recommends that the use of far-UVC radiation be regulated by a legal norm in order to avert a possible health risk to the population. It is recommended to aim for protection of the population at least at the level of the existing occupational health and safety regulations, which are based on the ICNIRP exposure limits. In addition, the SSK considers it necessary to provide special protection for vulnerable groups from the use of far-UVC radiation. In the medical field, the SSK considers the controlled, temporary use of far-UVC radiation, e.g. for prophylactic disinfection, to be justifiable from a radiation protection point of view, provided that it is carried out after prior consideration of the benefits and risks.