Influence of the background total volume mixing air delivery system on the exposure induced by cough for a hybrid personalized ventilation system

Abstract

Exposure generated with cough released droplets was investigated in a field environmental chamber (FEC) supplied with a hybrid ventilation system consisting of Desktop Personalized Ventilation (DPV) and Mixing Ventilation (MV). A Breathing Thermal Manikin (BTM) was placed in the middle of FEC while simulated coughs were released directly to the BTM at distances of 1, 2, 3 and 4 m from the front. These simulated coughs were generated by a cough machine which replicates droplet puffs similar in number, size distribution and velocity to human coughs. Results show that background concentration produced with total volume air delivery system significantly influences droplet concentration in the breathing zone when Desktop Personalized Ventilation (DPV) was applied for cough release at 1m and 2 m. When cough was released from a distance of 3 m from the target DPV flow is preserved throughout the exposure time and is able to dilute breathing zone concentration and significantly reduce impact of the background MV system. When cough was released from 4 m distance, DVP flow was able to dilute the breathing zone concentration to the similar level regardless of the background concentration.