Contents lists available at ScienceDirect Journal of Aerosol Science journal homepage: www.elsevier.com/locate/jaerosci Numerical simulation of welding fume lung dosimetry Jianan Zhao a , Yu Feng a,* , Marcio Bezerra b , Jun Wang b , Ted Sperry a a School of Chemical Engineering, Oklahoma State University, Stillwater, OK, USA b Department of Occupational and Environmental Health, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA ARTICLE INFO Keywords: Computational fluid-particle dynamics (CFPD) Welding fume Welding gas Lung dosimetry ABSTRACT Exposures to the airborne particles and toxic gases generated by welding fabrication activities will potentially lead to various diseases. Accurate information on the transport and deposition of such aerosols in the respiratory system is critically needed for precise health risk assessments. To address the data demand mentioned above, a multiscale computational fluid-particle dynamics (CFPD) model was developed in this study. Specifically, a virtual fabrication shop was integrated with a virtual human in the numerical model to evaluate the effects of ventilation condition, particle size, and gas species on the lung uptakes of those welding fume particles and gases. Welding fume particle and gases transmission, transport, and deposition have been simulated and analyzed starting from the emission source to the subject-specific human respiratory system via oral inhalation. Spherical iron particles with diameters of 100, 190, and 830 nm were simulated. The transport and absorption of NO x and CO were predicted too. Steady-state inhalation with 11.87 L/min was applied with two different air filter ventilation conditions. The numerical re- sults indicate that the ventilation condition can significantly influence welding gas transport and deposition. The pulmonary gas absorption rate is much higher at poor ventilation conditions. The air-tissue absorption coefficient is another crucial factor that can impact pulmonary gas ab- sorption. The total particle deposition fractions (TDFs) from mouth/nose to generation 6 (G6) are less than 18.0%, and particles mostly deposit in the oral cavity. Regional and local particle de- position data demonstrate that particles tend to enter the two upper lobes more than the other three lobes. In summary, this study paves the way to build a personalized in silico tool based on CFPD models for noninvasive precise health risk assessments associated with different welding activities. 1. Introduction Inhaling metal fume particles or gases generated by welding activities can cause serious health problems for workers. The particle size range is from 100 nm to 800 nm approximately (Wang, Hoang, Floyd, & Regens, 2017). The exposure to these aerosols poses severe health threats to workers as the toxic components can cause respiratory diseases, neurological ailments, and ultimately cancer (Hannu, Piipari, Tuppurainen, Nordman, & Tuomi, 2007; Sjögren, Hansen, Kjuus, & Persson, 1994). High-level exposures to welding fumes have been demonstrated to also cause acute systemic inflammation (Kim, Chen, Boyce, & Christiani, 2005). Meanwhile, different gases are generated via vaporization and oxidization of the workpieces and the surrounding gases during the welding process (Golbabaei & Khadem, 2015). The most common toxic gases emitted are ozone (O 3 ), nitrous gases (NO x ), and carbon https://doi.org/10.1016/j.jaerosci.2019.05.006 Received 21 April 2019; Received in revised form 29 May 2019; Accepted 29 May 2019 * Corresponding author. School of Chemical Engineering, Oklahoma State University, 420 Engineering North, Stillwater, OK, 74078, USA. E-mail address: yu.feng@okstate.edu (Y. Feng). Journal of Aerosol Science 135 (2019) xxx–xxx Available online 03 June 2019 0021-8502/ © 2019 Elsevier Ltd. All rights reserved. T