Experimental Study on the Effects of Temperature and Humidity on the Deposition of Nebulized Droplets in a Simplified Mouth-Throat Airway Model

YUEYANG CAI, Huizhen Yang, Xiaole Chen, Ting Ding, Nanjing Normal University

     Abstract Number: 171
     Working Group: Health-Related Aerosols

Abstract
The transport and deposition of saline droplets in human respiratory tract are complex due to droplet evaporation. The aim of this study is to experimentally investigate the effects of environmental temperature and humidity on the deposition of saline droplets in a simplified mouth-throat airway model. The normal saline droplets were generated from a vibrating mesh nebulizer (Youwell HL100A). The deposition fractions (DFs) of nebulized saline droplets in the MT airway model were compared under three conditions: 1) indoor condition, T=26.5℃ and RH=50% and 2) cool and dry, T=15℃ and RH=40% and; 3) hot and humid, T=30°C and RH=75%. The results suggested that, for all three environmental conditions, the DF of the saline droplets firstly decreased with the increase of the inhalation flow rate from 15 L/min to 22.5 L/min. Then the DF gradually increased with the increase of the inhalation flow rate from 22.5 L/min to 60 L/min. For a given inhalation flow rate, warmer and more humid environment led to higher DF of the saline droplets in the MT airway. The DFs of the droplets under Condition 3 were 8.3% to 22.6% higher than those under Condition 2 at different inhalation flow rates.