From indoor exposure to inhaled particle deposition: A multiphase journey of inhaled particles
Indoor air quality and its effect on respiratory health are reliant on understanding the level of inhalation exposure, particle inhalability, and particle deposition in the respiratory airway. In the indoor environment, controlling airflow through different ventilation systems can reduce inhalation exposure. This produces a wide variety of complex flow phenomena, such as recirculation, coanda flow, separation, and reattachment. Airborne particles drifting through the air, that move within the breathing region become inhaled into nasal cavity the nostrils. Studies have developed the aspiration efficiency to assist in predicting the fraction of inhaled particles. Inside the nasal cavity, micron and submicron particle deposition occurs in very different ways (inertial impaction, sedimentation, diffusion) and different locations. In addition, fibrous particles such as asbestos are influenced by tumbling effects and its deposition mechanism can include interception. Indoor fluid-particle dynamics related to inhalation exposure and eventual deposition in the respiratory airway is presented. This study involves multi-disciplinary fields involving building science, fluid dynamics, computer science, and medical imaging disciplines. In the future, an integrated approach can lead to digital/in-silico representations of the human respiratory airway able to predict the inhaled particle exposure and its toxicology effect.
Keywordsinhalation exposure respiratory airway fluid-partide dynamics CFD particles
The author acknowledges the financial support for the research, authorship, and/or publication of this article from the Australian Research Council (Grant No. DP160101953).
- Anthony, T. R. 2010. Contribution of facial feature dimensions and velocity parameters on particle inhalability. Ann Occup Hyg, 54: 710–725.Google Scholar
- Anthony, T. R., Anderson, K. R. 2013. Computational fluid dynamics investigation of human aspiration in low-velocity air: Orientation effects on mouth-breathing simulations. Ann Occup Hyg, 57: 740–757.Google Scholar
- Murakami, S. 1992. Diffusion characteristics of airborne particles with gravitational setting in an convection-dominant indoor flow field. ASHRAE Transactions, 98: 82–97.Google Scholar
- Nielsen, P. B., Kato, S., Chen, Q. 1998. The selection of turbulence models for prediction of room airflow. ASHRAE Transactions, 104: 1119–1127.Google Scholar
- Sleeth, D. K., Vincent, J. H. 2009. Inhalability for aerosols at ultra-low windspeeds. J Phys: Conf Ser, 151: 012062.Google Scholar
- Stöber, W. 1972. Dynamic shape factors of nonspherical aerosol particles. In: Assessment of Airborne Particles. Charles Thomas: 249–289.Google Scholar