Particle movement in buildings (IMAGE) DOE/Pacific Northwest National Laboratory Caption When the infected person in the office to the left coughs, respiratory droplets containing viral particles exit via the office's vent in the ceiling. Some droplets exit the building, while some are sent back into the building and into multiple rooms through the air-handling unit. A PNNL team found that a high ventilation rate can increase viral particle levels downstream of a source room. Credit Illustration/Animation: Cortland Johnson/Sara Levine, Pacific Northwest National Laboratory Usage Restrictions Please use credit info License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.