This study was a “worse-case” scenario using the breathing patterns of a healthy man, in a room that was free of air currents, and an extremely fine-particle tracer in order to demonstrate the maximum distribution of exhaled air. Using laser smoke visualization methods, we have shown that exhaled air dispersed at maximal distances of 0.2, 0.22, 0.3, and 0.4 m (for contours of > 20%) lateral to the median sagittal line of the HPS when oxygen was delivered via a simple Hudson mask at increasing flows of 4, 6, 8, and 10 L/min respectively. Within these dispersal distances from the mask, the chance of exposure to the patient’s exhaled air is significantly > 20%. The closer to the patient, the higher the chance of exposure to the patient’s exhaled air. Thus, within dispersal distances of 0.16, 0.17, 0.25, and 0.35 m, there was at least a 60% chance of exposure to the exhaled air at oxygen flows of 4, 6, 8, and 10 L/min, respectively. Coughing increased the air dispersion distance from 0.17 m (without coughing in Fig 2, top right, B) to 0.2 m while the HPS was receiving 6 L/min of oxygen with at least a 60% chance of exposure within that distance. These findings have important clinical implications for the health-care workers who often manage patients with respiratory failure due to CAP of unknown etiology at a short distance. It is important to provide adequate respiratory protection for the health-care workers, in addition to applying standard, contact, and droplet precautions in order to prevent nosocomial infections.