Imagine pulling out a UV device in your backpack and sanitizing bus seats or restaurant tables.
The disinfecting properties of UV light have long been known, along with the dangers of human exposure to UV light. A new study from the Linden Research Group, recently published in the journal Science of the Total Environment, confirms the safety of a new portable handheld disinfector using a technology called Far UV-C. The device is safe to use without skin and eye protection.
Ben Ma, a postdoctoral researcher in environmental engineering, was the original author of the paper. In this study, he examined the reflectance of ultraviolet light emitted by the device in various common materials and compared it to his conventional mercury-based UV-C device.
In this study, unlike conventional UV devices that emit at 254 nm, a new handheld device that emits deep UV-C rays at 222 nm does not produce a harmful amount of reflected UV light to the user or nearby people. , has been proven to be safe. It can be used as a personal surface disinfection device in hospitals and medical facilities, while traveling, or in restaurants and gyms.
We asked Ma to share more about this research and his experience as a postdoctoral fellow at CU Boulder.
Do you assume people have personal devices and sanitize their seats when they go to the cinema, for example?
That’s the basic idea. We are working with a startup company (Freestyle Partners, LLC) that already has a prototype. This company is a handheld UV device with a battery. Using this device on a surface, he can kill 99.9% of pathogens like SARS-CoV-2 within seconds. So it’s very effective and very safe.
Can you tell us a little bit about this paper and its impact?
The focus of this paper is to evaluate and determine the intensity of reflected radiation from this surface disinfection device. So if a surface reflects UV rays, they can bounce back to the person holding it or others around them. The reason we study reflection is that UV radiation can be harmful to human health. Also, if he uses a UV device to sanitize a surface, it’s most likely a reflective exposure, not from the device.
The study tested 21 materials commonly found in public spaces. We researched different materials because different materials have different reflectivity. For example, metal tends to be more reflective than plastic.
Why is this emerging technology safer?
Germicidal radiation has wavelengths between 200 and 280 nanometers. One of the new technologies that we are very interested in is far UV-C portable handheld devices that emit primarily at 222 nanometers. 222 nanometer ultraviolet radiation is much safer for humans compared to the 254 nanometer emitted from conventional mercury-based devices, which are known to be dangerous when exposed to human skin and eyes. .
222 nanometer UV radiation can effectively inactivate all kinds of pathogens, but it penetrates cells very poorly. It can be blocked by the top layer of human skin and eyes, but 254-nanometer radiation penetrates that layer to reach sprouting cells, resulting in adverse health effects. , showed that the new far-UVC device was 23 times safer for eye exposure and 43 times safer for skin exposure than conventional UV.
We also calculated the maximum exposure time and found that, in most cases, the new technology is safe to use for surface disinfection for more than 8 hours a day, even considering the worst case scenario.
Scientists say most exposure to COVID is aerosol, not surface contamination. So why is this an important disinfection tool?
While we agree that exposure to COVID is primarily through aerosols, surfaces remain a source of transmission for SARS-CoV-2, with COVID and other pathogens of concern surviving on surfaces for up to several days. There is a possibility. If not disinfected, it can become contagious. There are also studies showing that this emerging far-UV-C technology can also be used for aerosol disinfection in occupied public spaces such as elevators, restaurants and hospitals.
Looking to the future, could this paper have a sizable impact?
Overall, we hope this amazing technology will be used to mitigate the impact of pandemics and future public health events.
We are currently primarily focused on SARS-CoV-2. But in the real world, we encounter pathogens everywhere every day. So, for example, this device can also be used in the kitchen to disinfect food, cutting boards and utensils from pathogens. If you camp or hike, we have a product on the market that actually uses UV to disinfect stream water.
What are the next steps for this research project?
Our work supports further industry development of UV applications in terms of evaluating the reflectance and safety of these types of light sources. We continue to explore these and other UV wavelengths for public health protection in air, water and surfaces.
Our group is working on another study to standardize test methods for evaluating UV surface disinfection performance. Currently, there is no standardized method for evaluating the effectiveness of UV disinfection equipment. This study may provide important guidance for the real-world adoption of this technology to control not only current pandemics, but future pandemics and pathogens we encounter.
Original: Personal disinfection devices safe for use in public spaces, study finds
Than: University of Colorado Boulder
