Radiation protection for UVC air purifiers only partially ensured

Room air disinfection with UVC Source: abramov_jora/Stock.adobe.com

Since the coronavirus pandemic, the disinfection of indoor air and surfaces with UVC radiation has become increasingly important. Publicly accessible buildings in particular have been equipped with UVC air purifiers. These include hotels, restaurants, and medical practices. The devices are also used privately. However, the use of UV radiation also poses certain risks for the skin and eyes. The Federal Office for Radiation Protection (BfS) has therefore had 41 devices tested for their safety as part of a research project.

The result: sufficient UV protection is possible and is also being implemented in some cases. However, there are also devices for which a direct hazard to the eyes and skin cannot be ruled out and is even to be expected in some cases. The study also shows that the manufacturer's information does not always reflect the actual risk.

In principle, UVC radiation is able to kill bacteria and viruses. Key applications of UVC radiation include the sterilisation of surfaces, the disinfection of indoor air, and the treatment of water. The effectiveness depends on the dose. In order to be able to kill off micro-organisms and viruses to the desired extent, the radiation intensity must be sufficiently high and the exposure time sufficiently long. The effectiveness of the devices was not investigated in the study.

UV radiation has been proven to be carcinogenic

Because UV radiation can damage the skin and eyes and has been shown to be carcinogenic, UVC disinfection devices should be used only in such a way that prevents human exposure to radiation. Under no circumstances should UVC radiation be used on the body.

In the study, 41 devices with UV radiation sources were analysed and assessed with regard to the risk to eyes and skin posed by the devices. These included 20 mobile air purifiers, 11 disinfection wands, and open-air emitters.

41 different devices in the test Source: Martina/Stock.adobe.com

Closed systems perform best with mobile UV air purifiers. Around half of these devices are also suitable for use in nurseries and schools because they emit little or no measurable UV radiation. In contrast, there is a considerably increased risk in the group of free-standing radiators; for these risks, the safety measures provided by the manufacturers are not always sufficient. It is not advisable to use a do-it-yourself model that does not include any safety mechanisms.

The manufacturer's information is often insufficient

It is the responsibility of the manufacturer to ensure that the product is safe and that protection against UVC radiation is maintained when using the devices. The study therefore also evaluated manufacturer information on safe handling. A comparison of the manufacturer’s specifications with the measurement results shows that some of the devices tested emit more UV radiation than specified by the manufacturer. Furthermore, some devices were incorrectly or insufficiently labelled – also with regard to the necessary warnings.

UVC radiation has long been used to disinfect air, water, and surfaces as well as foodstuffs. This form of disinfection is used when no one is present in the room or when the source is installed in such a way that anyone present is not exposed to radiation. From the point of view of radiation protection, these applications are unproblematic.