UVC cabin development for N95 medical masks disinfection

  • Susana Oliveira de SOUZA
  • Carlos Leandro Silva dos PRAZERES
  • Jodnes Sobreira VIEIRA
  • Wandson ALMEIDA
  • Aquiles S ales Craveiro SARMENTO
  • Paula Viviane Dantas da CRUZ
  • Eraldo Nascimento OLIVEIRA
  • Márcia Regina Pereira ATTIE
  • Walderi Monteiro da SILVA JÚNIOR


The N95 disposable face mask is Personal Protective Equipment (PPE). It is intended to protect the user against the inhalation of infectious agents transmitted by air and also against the risk of droplet transmission. Although N95 masks are recommended for professionals in close contact with patients, the current COVID-19 pandemic has led to a significant shortage of this PPE. Prolonged use hardly reduces the protection offered by such a mask, and studies have supported the information that disposable respirators can work for weeks to months. However, Filtering Facepiece Respirator, after use, may contain various viruses and bacteria, and their disinfection is recommended. Germicidal irradiation with ultraviolet light (UVGI) at 254 nm, a disinfection method widely used in the world, was tested in N95 masks and showed that it preserves its filtration performance even at very high doses. Due to the need to reuse PPE by health professionals, low-cost illuminating cabin with UVGI light was produced for distribution in health institutions. The cabin was tested for dosimetric efficiency, with an average dose rate of 8.56 mW/cm2, demonstrating that in less than 2 min it reached the dose of 1 J/cm2, as well as successfully passed a preliminary bacteriological test, demonstrating that the UVC cabin had good effects for decontamination. In this work, in addition to these results, construction details for similar systems are presented and strategies for their implementation in health institutions are indicated. Even with the end of the pandemic, the cabins can be used to disinfect other objects in these same health institutions.

Keywords: UVC, mask decontamination, COVID-19.