Experimental investigation on reduced exposure to pollutants indoors by applying wearable personalized ventilation

A wearable personalized ventilation unit able to improve inhaled air quality and reduce risk from airborne disease contamination is reported. The performance of the personalized ventilation device relies on control over the flow interaction near the face of a person by inserting a reduced amount of clean air into the breathing zone. Experiments at 23 degrees C (73.4 degrees F) were performed in a full-scale test room with a breathing thermal manikin resembling a seated occupant in a state of thermal comfort, with a realistic free convection flow around the body and breathing cycle. The room air was mixed with tracer gas. The personalized ventilation supplied isothermally clean air from circular or elliptical nozzles of different diameters (equivalent diameter: 0.025-0.035m [0.08-0.12 ft]) positioned near the mouth of the manikin. The enhancement of inhaled air quality was studied by varying the initial velocity (0.2-0.6m/s [0.66- 1.97 fps]), the distance between the nozzles and the mouth (0.02-0.06m [0.07-0.2 ft]), or the direction of the jet (front, side, or below). The personalized ventilation made it possible to increase up to 94% the portion of clean air into the air inhaled. A wearable personalized ventilation unit can significantly reduce (more than six times) the number of secondarily infected occupants compared to mixing ventilation.