Euler-Lagrange Prediction of Diesel-Exhaust Polydisperse Particle Transport and Deposition in Lung: Anatomy and Turbulence Effects

Mohammad S Islam,Tevfik Gemci,Ian A Yang,Emilie Sauret,Zoran Ristovski,Y T Gu,Suvash C Saha

doi:10.1038/s41598-019-48753-6

Abstract

In clinical assessments, the correlation between atmospheric air pollution and respiratory damage is highly complicated. Epidemiological studies show that atmospheric air pollution is largely responsible for the global proliferation of pulmonary disease. This is particularly significant, since most Computational Fluid Dynamics (CFD) studies to date have used monodisperse particles, which may not accurately reflect realistic inhalation patterns, since atmospheric aerosols are mostly polydisperse. The aim of this study is to investigate the anatomy and turbulent effects on polydisperse particle transport and deposition (TD) in the upper airways. The Euler-Lagrange approach is used for polydisperse particle TD prediction in both laminar and turbulent conditions. Various anatomical models are adopted to investigate the polydisperse particle TD under different flow conditions. Rossin-Rammler diameter distribution is used for the distribution of the initial particle diameter. The numerical results illustrate that airflow rate distribution at the right lung of a realistic model is higher than a non-realistic model. The CFD study also shows that turbulence effects on deposition are higher for larger diameter particles than with particles of smaller diameter. A significant amount of polydisperse particles are also shown to be deposited at the tracheal wall for CT-based model, whereas particles are mostly deposited at the carinal angle for the non-realistic model. A comprehensive, polydisperse particle TD analysis would enhance understanding of the realistic deposition pattern and decrease unwanted therapeutic aerosol deposition at the extrathoracic airways.

Highlights

Inhaled particle deposition in the respiratory tract is caused mainly by inertial impaction, Brownian diffusion, gravitational sedimentation, and interception[2]
This study considered only the first three-generation, and zero pressure outlet conditions are employed at all outlets
A triple bifurcation symmetric Weibel lung model, an idealized asymmetric lung model, and a realistic CT-scan model were considered in the present study

Summary

Introduction

Inhaled particle deposition in the respiratory tract is caused mainly by inertial impaction, Brownian diffusion, gravitational sedimentation, and interception[2]. A variety of in silico and in vivo models have been designed for particle TDs in the extrathoracic and intrathoracic airways[13,14,15,16,17,18,19,20,21] Most of these studies utilized monodisperse aerosol particles to look into the particle TD in the bifurcating airways. An in vivo model of submicron particle (d16-d84) TD in a child’s lung showed 72% ± 17% radioactive polydisperse aerosol deposition in the extra-thoracic upper airways[33]. There are no experimental or CFD studies that have been conducted for the comprehensive polydisperse particle TD in a realistic lung model as a function of different deposition parameters. This study used three different triple bifurcations (G0-G3) anatomical models, a CT-based realistic lung model, a symmetric, and an asymmetric model, to predict polydisperse aerosol particle TDs in the upper airways. A comprehensive analysis was conducted for the polydisperse particle TD in the right and the left lung

Objectives

Results

Conclusion