• Tawfiq Khoury, Pascal Lavergne, Chandala Chitguppi, Mindy Rabinowitz, Gurston Nyquist, Marc Rosen, and James Evans.
• Department of Otolaryngology, Head & Neck Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
• Otolaryngol Head Neck Surg. 2020 Jul 1; 163 (1): 151-155.

ObjectivesThis study aimed to identify escape of small-particle aerosols from a variety of masks using simulated breathing conditions. This study also aimed to evaluate the efficacy of a negative-pressure environment around the face in preventing the escape of small aerosolized particles.Study DesignThis study is an evaluation study with specific methodology described below.SettingThis study was performed in our institution's fresh tissue laboratory.Subjects And MethodsA fixed cadaver head was placed in a controlled environment with a black background, and small-particle aerosols were created using joss incense sticks (mass-median aerosol diameter of 0.28 µ). Smoke was passed through the cadaver head, and images were taken with a high-resolution camera in a standardized manner. Digital image processing was used to calculate relative amounts of small-particle escape from a variety of masks, including a standard surgical mask, a modified Ambu mask, and our negative airway pressure respirator (NAPR).ResultsSignificant amounts of aerosolized particles escaped during the trials with no mask, a standard surgical mask, and the NAPR without suction. When suction was applied to the NAPR, creating a negative-pressure system, no particle escape was noted.ConclusionWe present a new and effective method for the study of small-particle aerosols as a step toward better understanding the spread of these particles and the transmission of coronavirus disease 2019. We also present the concept of an NAPR to better protect health care workers from aerosols generated from the upper and lower airways.

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