Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 12 2 2020 07 30 176 179 EN Anahita Fakherpour Department of Occupational Health, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran Mehdi Jahangiri Department of Occupational Health, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran 2020 09 08 2020 09 09 Abstract According to the hierarchy of hazard controls, respiratory protective ‎equipment (RPE) is considered as the last prevention and control measure ‎against chemical and biological respiratory hazards. However, the correct ‎application of‎ these kinds of personal protective equipment (PPE) as the only ‎control means are inevitably unavoidable during aerosol-generating procedures ‎‎ (AGPs) such as tracheal intubation, noninvasive ventilation, and ‎tracheostomy and so on‎. Nonetheless, two vital factors influencing the optimal use of RPE are as ‎follows: the filtration efficiency of the respirator and the fitting characteristics ‎of the respirator into the subjects’ facial dimensions to ensure the appropriate ‎respiratory protection. It is of utmost importance for HCP, while they are conducting high-risk ‎procedures during emergencies such as the outbreak of the Covid-19‎.   https://ijoh.tums.ac.ir/index.php/ijoh/article/view/466 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/466/621