Emissions, airflow patterns and modeling of test compounds in controlled hospital environments

Spreading and distribution of selected volatile organic compounds (VOCs) released as point source emissions in a hospital environment were investigated in two office rooms and two patient rooms. Six tracer compounds were released from six locations and their concentrations were measured in five sampling sites during two consecutive days. The air flow rates, velocity and flow direction, air temperature, pressure differences between adjacent rooms, and relative humidity and concentrations of the tracer compounds were measured. The results revealed that the size of the examined space and ventilation rates, the monitoring point should be either close to the exhaust terminal device or in the middle of the occupied zone the way that supply air flows do not interfere the measurements. Depending on the inlet terminal device and its location, the air is either delivered parallel to the ceiling or it can be directed to a desired spot into the occupied zone. The tracer compounds did spread evenly within the room and their concentrations decreased inversely with the distance. In rooms with a good ventilation, the concentrations at the exhaust air terminal units were close to those measured near the source point. The results obtained from modeling were consistent with the measurements.