Chavez-Ruiz M, Rueda-Torres L, Ruffner-Camargo B, Bellido-Achahui C. Methodology for evaluating the level of respiratory protection of masks and respirators against particles similar to those that transmit SARS-CoV-2. Rev Peru Med Exp Salud Publica. 2021;38(3):391-8. doi:10.17843/rpmesp.2021.383.8036