Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method

1996 ◽  
Vol 81 (5) ◽  
pp. 2203-2213 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu ◽  
P. Dewitt ◽  
T. R. Gerrity
Keyword(s):  
Particle Diameter ◽  
Deposition Efficiency ◽  
Dead Volume ◽  
Delivery Method ◽  
Constant Flow Rate ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction

Kim, Chong S., S. C. Hu, P. DeWitt, and T. R. Gerrity.Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method. J. Appl. Physiol. 81(5): 2203–2213, 1996.—Detailed regional deposition of inhaled particles was investigated in young adults ( n = 11) by use of a serial bolus aerosol delivery technique. A small bolus (45 ml half-width) of monodisperse aerosols [1-, 3-, and 5-μm particle diameter ( D p)] was delivered sequentially to a specific volumetric depth of the lung (100–500 ml in 50-ml increments), while the subject inhaled clean air via a laser aerosol photometer (25-ml dead volume) with a constant flow rate (Q˙ = 150, 250, and 500 ml/s) and exhaled with the same Q˙ without a pause to the residual volume. Deposition efficiency (LDE) and deposition fraction in 10 local volumetric regions and total deposition fraction of the lung were obtained. LDE increased monotonically with increasing lung depth for all three D p. LDE was greater with smaller Q˙ values in all lung regions. Deposition was distributed fairly evenly throughout the lung regions with a tendency for an enhancement in the distal lung regions for D p = 1 μm. Deposition distribution was highly uneven for D p = 3 and 5 μm, and the region of the peak deposition shifted toward the proximal regions with increasing D p. Surface dose was 1–5 times greater in the small airway regions and 2–17 times greater in the large airway regions than in the alveolar regions. The results suggest that local or regional enhancement of deposition occurs in healthy subjects and that the local enhancement can be an important factor in health risk assessment of inhaled particles.

Regional deposition of inhaled particles in human lungs: comparison between men and women

1998 ◽  
Vol 84 (6) ◽  
pp. 1834-1844 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Particle Diameter ◽  
Flow Rates ◽  
Men And Women ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction ◽  
The Difference

We measured detailed regional deposition patterns of inhaled particles in healthy adult male ( n = 11; 25 ± 4 yr of age) and female ( n = 11; 25 ± 3 yr of age) subjects by means of a serial bolus aerosol delivery technique for monodisperse fine [particle diameter ( D p) = 1 μm] and coarse aerosols ( D p = 3 and 5 μm). The bolus aerosol (40 ml half-width) was delivered to a specific volumetric depth (Vp) of the lung ranging from 100 to 500 ml with a 50-ml increment, and local deposition fraction (LDF) was assessed for each of the 10 local volumetric regions. In all subjects, the deposition distribution pattern was very uneven with respect to Vp, showing characteristic unimodal curves with respect to particle size and flow rate. However, the unevenness was more pronounced in women. LDF tended to be greater in all regions of the lung in women than in men for D p = 1 μm. For D p = 3 and 5 μm, LDF showed a marked enhancement in the shallow region of Vp ≤ 200 ml in women compared with men ( P < 0.05). LDF in women was comparable to or smaller than those of men in deep lung regions of Vp > 200 ml. Total lung deposition was comparable between men and women for fine particles but was consistently greater in women than men for coarse particles regardless of flow rates used: the difference ranged from 9 to 31% and was greater with higher flow rates ( P < 0.05). The results indicate that 1) particle deposition characteristics differ between healthy men and women under controlled breathing conditions and 2) deposition in women is greater than that in men.

Factors Influencing the Regional Deposition of Inhaled Particles in Man

1983 ◽  
Vol 64 (1) ◽  
pp. 69-78 ◽  
Author(s):  
M. J. Chamberlain ◽  
W. K. C. Morgan ◽  
S. Vinitski
Keyword(s):  
Regional Differences ◽  
Particle Deposition ◽  
Normal Subjects ◽  
Radioactive Aerosol ◽  
Breathing Rate ◽  
Regional Ventilation ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Normal Human

1. Although ventilation in normal human lungs has been shown to decrease from apex to base, comparable observations are lacking in regard to particle deposition. 2. We compared regional ventilation and particle deposition in normal subjects by using radioactive xenon and a radioactive aerosol while sitting, lying, and while breathing at an increased rate. Both smokers and non-smokers were studied. 3. Particle deposition and ventilation were closely related, and the greater the ventilation the greater the deposition of particles, a situation which prevailed irrespective of position and breathing rate. While supine, the apex to base gradient for both ventilation and particle deposition decreased but did not entirely disappear. At higher respiratory rates, central deposition of particles, especially in smokers, increased. 4. We concluded that there are regional differences in the deposition of particles and that such differences are closely related to regional ventilation.

scholarly journals Numerical Simulation of the Aerosol Particle Motion in Granular Filters with Solid and Porous Granules

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 268
Author(s):  
Olga V. Soloveva ◽  
Sergei A. Solovev ◽  
Ruzil R. Yafizov
Keyword(s):  
Numerical Simulation ◽  
Aerosol Particle ◽  
Particle Deposition ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Hydrodynamic Resistance ◽  
Hydrodynamic Properties ◽  
Granular Filters ◽  
Limiting Value ◽  
Good Agreement

In this work, a study was carried out to compare the filtering and hydrodynamic properties of granular filters with solid spherical granules and spherical granules with modifications in the form of micropores. We used the discrete element method (DEM) to construct the geometry of the filters. Models of granular filters with spherical granules with diameters of 3, 4, and 5 mm, and with porosity values of 0.439, 0.466, and 0.477, respectively, were created. The results of the numerical simulation are in good agreement with the experimental data of other authors. We created models of granular filters containing micropores with different porosity values (0.158–0.366) in order to study the micropores’ effect on the aerosol motion. The study showed that micropores contribute to a decrease in hydrodynamic resistance and an increase in particle deposition efficiency. There is also a maximum limiting value of the granule microporosity for a given aerosol particle diameter when a further increase in microporosity leads to a decrease in the deposition efficiency.

scholarly journals Particle Deposition Characteristics and Efficiency in Duct Air Flow over a Backward-Facing Step: Analysis of Influencing Factors

2019 ◽  
Vol 11 (3) ◽  
pp. 751
Author(s):  
Hao Lu ◽  
Li-zhi Zhang
Keyword(s):  
Particle Deposition ◽  
Air Flow ◽  
Deposition Velocity ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Reynolds Stress Model ◽  
Expansion Ratio ◽  
Particle Model ◽  
Duct Flow ◽  
Backward Facing Step

Dry deposition of airborne particles in duct air flow over a backward-facing step (BFS) is commonly encountered in built environments and energy engineering. However, the understanding of particle deposition characteristics in BFS flow remains insufficient. Thus, this study investigated particle deposition behaviors and efficiency in BFS flow by using the Reynolds stress model and the discrete particle model. The influences of flow velocities, particle diameters, and duct expansion ratios on particle deposition characteristics were examined and analyzed. After numerical validation, particle deposition velocities, deposition efficiency, and deposition mechanisms in BFS duct flow were investigated in detail. The results showed that deposition velocity in BFS duct flow monotonically increases when particle diameter increases. Moreover, deposition velocity falls with increasing expansion ratio but rises with increasing air velocity. Deposition efficiency, the ratio of deposition velocity, and flow drag in a BFS duct is higher for small particles but lower for large particles as compared with a uniform duct. A higher particle deposition efficiency can be achieved by BFS with a smaller expansion ratio. The peak deposition efficiency can reach 33.6 times higher for 1-μm particles when the BFS expansion ratio is 4:3. Moreover, the “particle free zone” occurs for 50-μm particles in the BFS duct and is enlarged when the duct expansion ratio increases.

Calculated deposition of inhaled particles in the airway generations of normal subjects

1979 ◽  
Vol 47 (4) ◽  
pp. 867-873 ◽  
Author(s):  
T. R. Gerrity ◽  
P. S. Lee ◽  
F. J. Hass ◽  
A. Marinelli ◽  
P. Werner ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Surface Concentration ◽  
Normal Subjects ◽  
Lung Model ◽  
Iron Oxide Particles ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Oxide Particles ◽  
Predicted Values ◽  
Good Agreement

Detailed regional deposition of inhaled particles in the human lung is calculated for individual airway generations. The calculations are based on Landahl's deposition model as applied to the morphometric lung model of Weibel. We consider primarily deposition patterns of iron oxide particles with diameters ranging between 1 and 10 micrometers, but we also calculate patterns of deposition for bis(2-ethylhexyl) sebacate particles with diameters as small as 0.2 micrometers. We obtain good agreement between predicted values and observed values for alveolar retention of inhaled iron oxide particles with 64 and 20% of total deposition predicted to occur in nonciliated airways for 2- and 5-micrometer particles, respectively. This is compared with 48 +/- 9 and 27 +/- 10% for the measured values. Calculated values for total lung deposition of small bis(2-ethylhexyl) sebacate particles agree well with experimental data. The calculations show a minimum in deposition occurring for particle diameters of 0.5 micrometers, which is in agreement with observations. A calculation of surface concentration of deposited 7.9-micrometer aerodynamic particles reveals a very large concentration occurring at airway generation four. This observation is considered in light of observations that bronchial carcinomas occur in this vicinity of the lung.

Comparison of Micro- and Nano-Size Particle Transport and Depositions in 90 Degree Bend Microchannel

2009 ◽  
Author(s):  
Kai Zhang ◽  
Jianzhong Lin ◽  
Mingzhou Yu
Keyword(s):  
Particle Size ◽  
Electric Field ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Particle Deposition ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Size Particle ◽  
Volume Method ◽  
Nano Size

The flow and electric field are simulated numerically with finite volume method first, then large number of nanoparticles and microparticles are injected into the microchannel separately, and these particles are traced with the Lagrangian method. It has been found that particle deposition efficiency in the bend usually decreases first then increases with particle size increasing, and there usually exists a minimum value and it corresponds to the particle diameter of about 3μm, which means that kind of particle can transport longer distance. The electric field doesn’t affect that specified value. This conclusion is helpful to the optimization of the design of microchips.

Deposition Fraction of Ellipsoidal Particles in a Fully Developed Laminar Pipe Flow: Application of New Correlations for Hydrodynamic Forces and Torques

2014 ◽  
Author(s):  
Mohammad Mehdi Tavakol ◽  
Omid Abouali ◽  
Mahmood Yaghoubi ◽  
Goodarz Ahmadi
Keyword(s):  
Pipe Flow ◽  
Deposition Efficiency ◽  
Hydrodynamic Forces ◽  
Transport Processes ◽  
Creeping Flow ◽  
Spherical Particles ◽  
Low Reynolds Number Flows ◽  
Ellipsoidal Particles ◽  
Deposition Fraction ◽  
Laminar Pipe Flow

The physics of transport, deposition, detachment and reentrainment re-entrainment of particles suspended in a fluid are of great interests in many practical fluid engineering problems. For spherical particles, analysis of their translational motions is sufficient for a complete description of their transport processes. Prediction of transport and deposition of non-spherical particles, however, is more complicated due to the coupling of particle translational and rotational motions. Most studies related to dispersion of ellipsoidal particles used the traditional creeping flow formulations for hydrodynamic forces and torques. These formulations are valid for very low Reynolds number flows. In this study, dispersion and deposition of ellipsoidal particles in a fully developed laminar pipe flow are analyzed numerically using new correlations for hydrodynamic forces and torques. The deposition efficiency of the ellipsoidal particles in laminar pipe flow are calculated and the results are compared with other theoretical and numerical studies and good agreement is observed.

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