In vitro deposition measurement of inhaled micrometer-sized particles in extrathoracic airways of children and adolescents during nose breathing

Golshahi, Laleh; Noga, Michelle; Thompson, Richard B.; Finlay, Warren H.

doi:10.1016/j.jaerosci.2011.04.002

Cited by 89 publications

(90 citation statements)

References 44 publications

(59 reference statements)

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“…The dimension D was obtained by a series calculation using the airway volume (V) and length (L) obtained from the AR measurements. However, the equations given by Storey-Bishoff et al (2008) and Golshahi et al (2011), involving subject-specific Re and Stk, do not fit the data of Taiwanese adults. Since the subjects in Storey-Bishoff et al (2008) and Golshahi et al (2011) were infants and children, the authors believe that age difference is the major reason for the discrepancy.…”

Section: Resultsmentioning

confidence: 91%

“…In order to compare the nasal deposition between ethnic groups, Reynolds (Re) and Stokes number (Stk) using the dimension D as defined by Storey-Bishoff et al (2008) and Golshahi et al (2011), respectively, were employed to fit the data of the present study. The dimension D was obtained by a series calculation using the airway volume (V) and length (L) obtained from the AR measurements.…”

Section: Resultsmentioning

confidence: 99%

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In-Vivo Measurements of Micrometer-Sized Particle Deposition in the Nasal Cavities of Taiwanese Adults

Hsu

Chuang

2012

Aerosol Science and Technology

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It has been observed that Asians and Caucasians possess considerably different craniofacial features, which may affect the anatomical structure of the upper respiratory tract and, consequently, the characteristics of particle deposition. Most deposition studies on the human respiratory tract were primarily based on a limited number of Caucasian subjects. Therefore, data of the particle deposition efficiency in the upper respiratory tract of Asians are needed to supplement the understanding of the deposition characteristics in the human respiratory tract. This study measured the nasal deposition efficiency of particles ranging from 0.5 to 20 µm in five Taiwanese male and four Taiwanese female adults under different inspiratory flow rates. The measured deposition efficiency showed a very large intersubject variability in the inertial parameters, ranging between 10 3 to 5 × 10 4 µm 2 cm 3 /s, and the deposition efficiency of the subjects with similar values of the minimum nasal cross-sectional area approaches to each other. This study showed that Taiwanese adults have lower nasal deposition efficiency than Caucasians, and that the differences in the nostril shape, inclination of nostrils, and nasal hair density between the two ethnic groups are likely the causes. In addition, this study suggested that up to 15% of overestimation in the nasal deposition efficiency for larger particles may occur if the inhalation efficiency is not considered. An empirical equation adopting inspiratory flow rate and the minimum nasal cross-sectional area was developed to predict the nasal particle deposition in the upper airway of Taiwanese adults.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

In-Vivo Measurements of Micrometer-Sized Particle Deposition in the Nasal Cavities of Taiwanese Adults

Hsu

Chuang

2012

Aerosol Science and Technology

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“…The verification of the children upper respiration tracts model was conducted by comparing the numerical results with some in vitro experiment data (Golshahi et al, 2011). The good agreement between CFD qualitative predictions of deposition rates and in vitro deposition results is shown in Fig.…”

Section: Model Validationmentioning

confidence: 86%

Computational Fluid Dynamics Simulation of Airflow Patterns and Particle Deposition Characteristics in Children Upper Respiratory Tracts

Liu

et al. 2012

Engineering Applications of Computational Fluid Mechanics

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ABSTRACT:As findings from studies of airflow patterns and particle deposition in the upper respiratory tracts (URTs) of adults may not be readily extrapolated to studies of the URTs of children, due to the differences in airway anatomy and breathing conditions, the effects of pediatric, physiological features on airflow patterns and particle deposition have been investigated utilizing an idealized model of the URTs of children. Particle deposition characteristics in a 0.01−10 mm spectrum were assessed employing a well-verified, Lagrangian tracking method for different inhalation flow rates, consistent with sedentary (3.5 L/min), light (7.0 L/min) and high (10.5 L/min) activity levels. The main results are: (1) airflow patterns during inhalation and exhalation modes are very different, while airflow patterns are similar during each inhalation or exhalation mode, while subject to three different airflow rates; (2) higher Stokes and impaction numbers are observed in the model for a 3 year old child, when compared to adults under comparably scaled activity levels; and (3) breathing airflow rates, particle diameters and particle densities are three key factors influencing particle deposition rates, with higher deposition rates for children observed when compared to adults under comparable activity levels. For identical impaction parameters, all deposition rates for children are also higher. The localized particle deposition rates in the mouth cavity are similar for children and adults, while those in the larynx, pharynx, trachea and bronchi are higher for children than for adults. Results of this study demonstrate that differences do exist between children and adults in both airflow distribution and aerosol deposition characteristics. These differences should be taken into account in the determination of children's risk exposure levels for airborne toxicants.

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“…At 60 L/min the number concentration of 5.3 µm particles was too low to be considered and at 90 and 120 L/min the number of 3.2 and 5.3 µm were too low; thus, those sizes were excluded at the associated flow rates. The variable dilution air, as a result of the resistance of the replica compared to the blank line, was corrected similar to our previous work (Storey-Bishoff et al 2008;Golshahi et al 2011a, b). The replica was also removed and the difference between the number concentration through the blank line and the replica line was measured and defined as the baseline, which was then subtracted from the total deposition.…”

Section: Methodsmentioning

confidence: 99%

“…Studies have been done by our group (Storey-Bishoff et al 2008;Golshahi et al 2011a) and others (Janssens et al 2001;Corcoran et al 2003;Minocchieri et al 2008;Laube et al 2010) to mimic pediatric deposition with airway models, mostly among infants and young children who are nose breathers. However, as for adults, there is a need for a single idealized model to consistently predict average pediatric deposition.…”

Section: Introductionmentioning

confidence: 99%

An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

Golshahi

Finlay

2012

Aerosol Science and Technology

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In vitro deposition measurement of inhaled micrometer-sized particles in extrathoracic airways of children and adolescents during nose breathing

Cited by 89 publications

References 44 publications

In-Vivo Measurements of Micrometer-Sized Particle Deposition in the Nasal Cavities of Taiwanese Adults

In-Vivo Measurements of Micrometer-Sized Particle Deposition in the Nasal Cavities of Taiwanese Adults

Computational Fluid Dynamics Simulation of Airflow Patterns and Particle Deposition Characteristics in Children Upper Respiratory Tracts

An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

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