The unprecedented worldwide effects of COVID-19 are going to be with us for the long haul; but we are slowly adapting and finding ways to cope with this pandemic. With this extended crisis, one of the challenges is the anticipated shortage of personal protective equipment (PPEs). One way to address this is to find means to safely recycle and reuse personal protective equipment. In the first few weeks of the pandemic, Prof Florencio Ballesteros of the Chemical and Environmental Engineering of the College of Engineering in UP Diliman proposed a sterilizing cabinet using ultraviolet (UV) irradiation. Using a plastic clothes cabinet and fitting it with UV fluorescent lamps, aluminum foil walls, and mesh wires to serve as trays; and equipping it with a timer, the cabinet is now ready for testing for disinfection of PPEs. Ultraviolet irradiation has been used for sterilization purposes for food, water, and in cases of pandemic, personal protective device.
The “UV Cabinet” was conceptualized to sterilize PPEs like N95 masks, face shields, coveralls, and goggles. Through collaborations between UP Diliman College of Engineering, UPM College of Public Health, and Surgical Innovation and Biotechnology Laboratory (SIBOL) of the UP College of Medicine, the disinfection unit was validated for disinfection of PPEs. Appropriate scientific validity testing methods proved that the UV Cabinet was capable of significantly disinfecting N95 masks from gram negative bacteria and spore-forming bacteria (whose durability is similar to corona virus) when treated with UV irradiation for 30-40 minutes. Disinfection of coveralls was also successful; however, since UV disinfection relies on a line-of-sight disinfection, meaning areas not reached by the UV light will not be disinfected, appropriate positioning of certain PPEs, especially coveralls will be needed to maximize disinfection. We hope that the UV Cabinet will be able to disinfect PPEs for extended use and reuse as a means of temporarily solving the shortages of PPEs in the healthcare setting until long-term solutions are available.
We wish to thank Prof Florencio Ballesteros and Dr. Maria Margarita Lota of the Medical Microbiology Department of the UP College of Public Health for their help.
DISCLAIMER: We advise against the inappropriate use of UV light as a means of disinfecting PPEs as UV light can cause photokeratitis, skin burns, and skin cancer from prolonged exposure.
Emmanuel P. Estrella, MD, MSc | Published in Healthscape Special COVID-19 Issue No. 12
