Xiaoyu Xu1,2,3, Yidan Shang2, Lin Tian 2, Wenguo Weng1, Jiyuan Tu 2,3,4

Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China
School of Engineering – Mechanical and Automotive, RMIT University, Bundoora, VIC 3082, Australia
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052, Australia
Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China

Received: November 6, 2018
Revised: February 25, 2019
Accepted: April 1, 2019
Download Citation: ||https://doi.org/10.4209/aaqr.2018.09.0343 

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Cite this article:
Xu, X., Shang, Y., Tian, L., Weng, W. and Tu, J. (2019). Inhalation Health Risk Assessment for the Human Tracheobronchial Tree under PM Exposure in a Bus Stop Scene. Aerosol Air Qual. Res. 19: 1365-1376. https://doi.org/10.4209/aaqr.2018.09.0343


  • Risk assessment of PM exposure was performed in a nasal-oral-tracheobronchial airway model.
  • 10 nm–1 µm particles can induce higher potential for lung disease than other sized particles.
  • Risk factors of the left, right, and 5 lung lobes were estimated.
  • Cr posed a higher chance for developing lung diseases than Ni and Mn.
  • Mn is considered more hazardous for human upper airway than Cr and Ni.


Inhalation exposure to airborne particulate matter (PM) can induce respiratory/cardiovascular disease and lung cancer in humans. Determining the specific particle deposition distribution in the human tracheobronchial tree is crucial to evaluating the health risk. Thus, an integrated human nasal-oral-tracheobronchial airway model was employed to study the particle deposition, and empirical equations for calculating the lung lobe risk contribution fractions were developed. The risk contribution of each lobe to non-carcinogenesis and carcinogenesis was predicted using prior experimental data collected at a bus stop. The regional inhalation health risk was analyzed by evaluating the hazard quotient (HQ) and excess lifetime cancer risk (ELCR) of selected non-carcinogenic and carcinogenic elements (viz., Cr, Mn, and Ni). Fine particles (10 nm–1 µm) contributed the highest risk fractions for the lung lobes, inducing higher potential health consequences in the lungs than coarser particles. Cr posed carcinogenic lung risks to people who commuted by public transport, with the ELCR to every lobe exceeding the recommended limit. The non-carcinogenic and carcinogenic risks were 1.5 times greater for the right lung than for the left lung. Of the lung lobes, the RLL incurred the highest risk, followed by the LLL, RUL, LUL, and RML. Inhalation exposure to Cr posed a much higher risk to the lungs than exposure to Ni and Mn. However, compared to the other two elements, Mn potentially induced a higher chance of developing upper respiratory disease.

Keywords: Tracheobronchial airway; Particulate matter; Chemical composition; Inhalation assessment; Lung lobe deposition.


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