Extrathoracic Airways Research Articles

In silico assessment of mouth-throat effects on regional deposition in the upper tracheobronchial airways

Regional deposition of inhaled medicines is a valuable metric of effectiveness in drug delivery applications to the lung. In silico methods are now emerging as a valuable tool for the detailed description of localized deposition in the respiratory airways. In this context, there is a need to minimize the computational cost of high-fidelity numerical approaches. Motivated by this need, the present study is designed to assess the role of the extrathoracic airways in determining regional deposition in the upper bronchial airways. Three mouth-throat geometries, with significantly different geometric and filtering characteristics, are merged onto the same tracheobronchial tree that extends to generation 8, and Large Eddy Simulations are carried out at steady inhalation flowrates of 30 and 60L/min. At both flowrates, large flow field differences in the extrathoracic airways across the three geometries largely die out below the main bifurcation. Importantly, localized deposition fractions are found to remain practically identical for particles with aerodynamic diameters of up to dp=4μm and dp=2.5μm at 30 and 60L/min, respectively. For larger particles, differences in the localized deposition fractions are shown to be mainly due to variations in the mouth-throat filtering rather than upstream flow effects or differences in the local flow field. Deposition efficiencies in the individual airway segments exhibit strong correlations across the three geometries, for all particle sizes. The results suggest that accurate predictions of regional deposition in the tracheobronchial airways can therefore be obtained if the particle size distribution that escapes filtering in the mouth-throat (ex-cast dose) of a particular patient is known or can be estimated. These findings open the prospect for significant reductions in the computational expense, especially in the context of in silico population studies, where the aerosol size distribution and precomputed flow field from standardized mouth-throat models could be used with large numbers of tracheobronchial trees available in chest-CT databases.

Measurement of nanoparticle exposure in crematoriums and estimation of respiratory deposition of the nanoparticles by number and size distribution.

Nanoparticles (NPs), including hazardous substances, are generated in crematoriums due to the high temperatures during the combustion process. NPs are reported to greatly impact animals' health by reaching the alveoli and being carried to the entire body through the blood stream. However, studies in crematoriums have yet to assess workers' exposure to the generated NPs. The purpose of this study is to assess workers' exposure to NPs released in crematoriums. Field surveys were conducted in three crematoriums with an emphasis on cremation, bone rearrangement and cleaning processes. The NP concentrations and size distributions were analyzed. The deposition of NPs in each respiratory region during each working process was calculated based on the measured data using the Human Respiratory Tract Model. The mean particle number concentration was maximized momentarily during the bone rearrangement process. The concentration at the time a crematory's door was opened was 500,000 particle/cm3. NPs aggregated to micro-sized particles within a few minutes, dust generated by the bone rearrangement, or both. As a result of model calculation, the mean ratios (alveolar per the other regions by a crematory) were approximately 3.0 (bronchus and bronchioles regions: except for the first survey in crematorium A which had the obstruction of measurement) and 4.3 (extrathoracic airways). The ratios were similar for all crematoriums. These results can be used for health risk assessments in crematoriums. In addition, these results should be applicable to estimate the inhalation unit risk of each respiratory organ such as lungs and nose.

The use of a thyroid shield for intraoral anterior oblique occlusal views-a risk-based approach.

To estimate the radiation dose reduction to the thyroid for an anterior oblique occlusal view from the use of a thyroid shield, compare this with the variation in thyroid dose resulting from differences in examination positioning and discuss the additional considerations associated with the use of a thyroid shield before making a recommendation on their routine use for this examination. Doses to the oral mucosa, the salivary glands, the thyroid, the extrathoracic airways, the oesophagus and the lungs were directly measured for anterior oblique occlusal X-rays of a Rando phantom with and without a thyroid shield using strips of calibrated XRQA Gafchromic film. The examination was also simulated using Monte Carlo software for the without thyroid shield case for a comparison of the dose and to evaluate the dosimetric effect of suboptimal examination positioning. A 36% reduction in thyroid dose was measured as a result of thyroid shield use; the effective dose reduction is of the order of 22%. Suboptimal positioning was found to increase thyroid dose by a far more significant amount. Despite the reduction in thyroid dose, cost-benefit considerations mean that the purchase of a thyroid shield is only recommended where a very high number of anterior oblique occlusal views are undertaken. Optimization efforts for this examination are better focussed on training in examination positioning.

Computer-aided generation and lung deposition modeling of nano-scale particle aggregates

The study sets its main focus on the introduction of a random-walk-based model for the generation of variably shaped particle aggregates consisting of a predefined number of spherical components. With the help of a well-defined algorithm, the user is enabled to select between isodimensional, chain-like and platelet-like aggregates, for which related aerodynamic parameters (dynamic shape factors, volume-equivalent diameters, aerodynamic diameters) are determined automatically. The theoretical approach for random aggregate construction is directly connected with the previously developed stochastic particle transport and deposition model. Thereby, individually shaped aggregates may be provided for each random-walk scenario taking place in the almost realistic lung structure. Preliminary application of the aggregate generation model was carried out by assuming single components with a constant diameter of 1 nm and unit-density (1 g cm−3) and variably shaped aggregates consisting of 10, 100 and 1000 components. Inhalation of the aggregate-loaded aerosol into lungs of average size (FRC = 3300 mL) was supposed to take place under sitting, light-exercise and heavy-exercise conditions. Results obtained from deposition modeling clearly show that, independent of aggregate geometry, total deposition declines with increasing number of components included in the particulate construct, but experiences a continuous enhancement with rising inhalation flow rate. Among the predefined geometric categories, platelet-like aggregates are distinguished by lowest deposition and isodimensional clusters by highest. While isodimensional aggregates preferentially deposit in the extrathoracic and bronchial airways, chain-like and platelet-like aggregates exhibit a significantly increased tendency to hit the alveolar walls.

Characterization of aerosol Stokes number in 90° bends and idealized extrathoracic airways

Prediction of aerosol deposition in the respiratory system is important for improving the efficiency of inhaled drug delivery and for assessing the toxicity of airborne pollutants. Deposition is typically reported as a function of a global Stokes number which is based on a reference flow timescale, or the ratio of the characteristic flow length and velocity scales. In reality, however, particles experience varying flow timescales as they are advected through the airways, which motivates the use of an instantaneous Stokes number based on the local properties of the flow field. We then define the effective Stokes number as the time-average of the instantaneous value. This effective Stokes number thus encapsulates the flow history and geometric variability, and provides a more detailed account of the particle trajectory in the flow. Laminar and turbulent flows in a curved pipe are examined first and provide a simplified, or canonical, configuration of the flow in the upper airways. They are followed by a study of turbulent flow in an idealized mouth–throat geometry. Our results demonstrate that the effective Stokes number can deviate significantly from the traditional value based solely on the reference flow timescale. In addition, the effective Stokes number shows a clear correlation with deposition efficiency and can therefore be used to determine optimal aerosol release locations in order to minimize extrathoracic losses.

Cancer incidence and mortality from exposure to radon progeny among Ontario uranium miners

ObjectivesThe study objectives were to extend the follow-up of the Ontario uranium miners cohort, one of the largest cohorts of uranium miners with low cumulative exposures, to examine the relationship...

Oscillatory flow in the human airways from the mouth through several bronchial generations

The time-varying flow is studied experimentally in an anatomically accurate model of the human airways from the mouth through several generations of bronchial branching. The airway geometry is obtained from the CT scan of a healthy adult male of normal height and build. The three-component, three-dimensional mean velocity field is obtained throughout the entire model using phase-locked Magnetic Resonance Velocimetry. A pulsatile pump drives a sinusoidal waveform (inhalation and exhalation) with frequency and stroke-length such that the mean trachea Reynolds number at peak inspiration is 4200 and the Womersley number is 7. Integral parameters are defined to quantify the degree of velocity profile non-uniformity (related to axial dispersion) and secondary flow strength (lateral dispersion). It is found that the extrathoracic airways significantly modify the tracheal flow and that the flow at the first bifurcation is highly asymmetric. The effect of flow oscillation is to produce time dependent flow features which are asymmetric with respect to the acceleration and deceleration periods surrounding peak inhalation and exhalation. This is most pronounced in regions of separation and on the secondary flow structure, which are sensitive to local attributes of the real anatomy. This is reflected in the integral parameters, which behave non-monotonically between successive bronchial generations. In general, the measured oscillatory flow in a realistic anatomy confirms many trends derived from idealized models but also possesses qualitatively different large scale flow structures as compared to idealized representations of the upper airways.

THE MAYAK WORKER DOSIMETRY SYSTEM (MWDS 2013): A RE-ANALYSIS OF USTUR CASE 0269 TO DETERMINE WHETHER PLUTONIUM BINDS TO THE LUNGS.

Radionuclides in ionic form can become chemically bound in the airways of the lungs following dissolution of inhaled particulates in lung fluid. The presence of long-term binding can greatly increase lung doses from inhaled plutonium, particularly if it occurs in the bronchial and bronchiolar regions. However, the only published evidence that plutonium binding occurs in humans comes from an analysis of the autopsy and bioassay data of United States Transuranium and Uranium Registries Case 0269, a plutonium worker who experienced a very high (58 kBq) acute inhalation of plutonium nitrate. This analysis suggested a bound fraction of around 8 %, inferred from an unexpectedly low ratio of estimated total thoracic lymph node activity:total lung activity, at the time of death. However, there are some limitations with this study, the most significant being that measurements of the regional distribution of plutonium activity in the lungs, which provide more direct evidence of binding, were not available when the analysis was performed. The present work describes the analysis of new data, which includes measurements of plutonium activity in the alveolar-interstitial (AI) region, bronchial (BB) and bronchiolar (bb) regions, and extra-thoracic (ET) regions, at the time of death. A Bayesian approach is used that accounts for uncertainties in model parameter values, including particle transport clearance, which were not considered in the original analysis. The results indicate that a long-term bound fraction between 0.4 and 0.7 % is required to explain this data, largely because plutonium activity is present in the extra-thoracic (ET2), bronchial and bronchiolar airways at the time of death.

A stochastic model of carbon nanotube deposition in the airways and alveoli of the human respiratory tract

Context: In the past two decades, possible exposure of workers to nanoparticles has excited the attention of occupational medicine, resulting in the conception of related risk assessments. Although most nanoparticles have been categorized as hazardous substances in the meantime, their behavior in the human respiratory tract still bears some enigmas, which require clarification.Objectives: The study pursues the goal to provide detailed theoretical lung deposition data of carbon nanotubes (CNT) with various diameters and lengths. Besides a quantification of total and regional deposition, also airway generation-specific deposition has been subjected to the modeling process.Methods: Theoretical approach of CNT deposition in the human lungs has been conducted by assuming a stochastic structure of the bronchial network, within which particle transport takes place along randomly selected paths. Fluid-dynamic particle characteristics have been simulated by application of a rigid fiber model, which considers diverse forces and torques acting on the particles during their translocation within the inhaled air. Particle deposition in the entire lungs has been approximated by using the aerodynamic/thermodynamic diameter concept and related empirical deposition formulae.Results: Theoretical deposition data reflect a significant dependence of CNT deposition on (a) the effective size of the particles and (b) the conditions, under which they are taken up into the respiratory tract. Extremely small CNT (∼1 nm) are primarily filtered in the extrathoracic airways, intermediately sized CNT (∼10 nm) exhibit a preference to deposit in the alveoli, and large CNT (∼100 nm) are marked by minimum deposition.Conclusion: Pulmonary deposition of CNT is subject to a partly remarkable variation. According to the model of this study, particles of intermediate size seem to bear highest potential to act as hazardous substances.

CFD Investigation of Human Tidal Breathing through Human Airway Geometry

This study compares the effect of the extra-thoracic airways on the flow through the lower airways by carrying out computational fluid dynamics (CFD) simulations of the airflow through the human respiratory tract. In order to facilitate this comparison, two geometries were utilized. The first was a realistic nine-generation lower airway geometry derived from computed tomography (CT) images, while the second included an additional component, i.e., an idealized extra-thoracic airway (ETA) coupled with the same nine-generation CT model. Another aspect of this study focused on the impact of breathing transience on the flow field. Consequently, simulations were carried out for transient breathing in addition to peak inspiration and expiration. Physiologically-appropriate regional ventilation for two different flow rates was induced at the distal boundaries by imposing appropriate lobar specific flow rates. The scope of these simulations was limited to the modeling of tidal breathing at rest. The typical breathing rates for these cases range from 7.5 to 15 breaths per minute with a tidal volume of 0.5 Liter (L). For comparison, the flow rates for constant inspiration/expiration were selected to be identical to the peak flow rates during the transient breathing. Significant differences were observed from comparing the peak inspiration and expiration with transient breathing in the entire airway geometry. Differences were also observed for the lower airway geometry. These differences point to the fact that simulations that utilize constant inspiration or expiration may not be an appropriate approach to gain better insight into the flow patterns present in the human respiratory system. Consequently, particle trajectories derived from these flow fields might be misleading in their applicability to the human respiratory system.

Spatial visualization of theoretical nanoparticle deposition in the human respiratory tract.

Although nanoparticles and their hazardous effects on human health are well elucidated meanwhile, inhalation and distribution of these materials in the human respiratory tract still represent partly enigmatic phenomena. Main objective of the present study was the detailed description of a mathematical method, with the help of which spatial distributions of nanoparticles deposited in the tracheobronchial tree may be visualized appropriately. The technique is founded on a stochastic model of the bronchial network, within which inhaled particles follow individual, randomly selected trajectories. The lengths of these random paths depend on the airway-specific deposition probabilities calculated for the particles and the duration of the breath cycle. Positions of the deposited material were determined by computation of the exact lengths of individual particle trajectories and the orientation of single path segments within a Cartesian coordinate system, where the z-direction corresponds with the trachea. For a better quantification of the particle distribution and its eventual comparison with experimental data particle coordinates were fitted into a voxel grid [1 voxel = (0.467 cm)(3)]. Particle deposition is chiefly controlled by diffusive processes, whereas deposition mechanisms associated with inertia or gravity play a subordinate role. Deposition patterns were visualized for particles with sizes of 1, 10, and 100 nm. As clearly demonstrated by the results obtained from the modeling procedure, under normal breathing conditions 1-nm particles tend to deposit in the upper airways, whilst 10- and 100-nm particles are preferably accumulated in the airways of the central and peripheral lung. The particle dose deposited in the extrathoracic and thoracic airways within one breath cycle significantly declines with increasing particle size. Based on the predictions presented in this study possible consequences of nanoparticle inhalation to the health of subjects increasingly exposed to these airborne materials were discussed.

Three-dimensional inspiratory flow in the upper and central human airways

The steady inspiratory flow through an anatomically accurate model of the human airways was studied experimentally at a regime relevant to deep inspiration for aerosol drug delivery. Magnetic resonance velocimetry was used to obtain the three-component, mean velocity field. A strong, single-sided streamwise swirl was found in the trachea and persists up to the first bifurcation. There, the swirl and the asymmetric anatomy impact both the streamwise momentum distribution and the secondary flows in the main bronchi, with large differences compared to what is found in idealized branching tubes. In further generations, the streamwise velocity never recovers a symmetric profile and the relative intensity of the secondary flows remains strong. Overall, the results suggest that, in real human airways, both streamwise dispersion (due to streamwise gradients) and lateral dispersion (due to secondary flows) are very effective transport mechanisms. Neglecting the extrathoracic airways and idealizing the bronchial tree may lead to qualitatively different conclusions.

Effects of steep Trendelenburg position for robotic-assisted prostatectomies on intra- and extrathoracic airways in patients with or without chronic obstructive pulmonary disease

The use of the steep Trendelenburg position and abdominal CO2-insufflation during surgery can lead to significant reduction in pulmonary compliance and upper airway oedema. The postoperative time course of these effects and their influence on postoperative lung function is unknown. Therefore, we assessed intra- and extrathoracic airway resistance and nasal air flow in patients with or without chronic obstructive pulmonary disease (COPD) during robotic-assisted prostatectomy. In 55 patients without and 20 patients with COPD spirometric measurements and nasal resistance were obtained before operation, 40 and 120 min, and 1 and 5 days after operation. We measured vital capacity (VC), forced expiratory volume in 1 s (FEV1), maximal mid-expiratory and inspiratory flow (MEF50, MIF50), arterial oxygen saturation, and nasal flow. The occurrence of postoperative conjunctival oedema (chemosis) was also assessed. In patients without COPD, MEF50/MIF50 increased and nasal flow decreased significantly after surgery (P<0.0001) and normalized within 24 h. VC and FEV1 decreased after operation with a nadir at 24 h and recovered to normal until the fifth day (P<0.0001). In patients with COPD, changes in MEF50/MIF50 and nasal flow were similar, while changes in VC and FEV1 lasted beyond the fifth day (P<0.0001). Robotic-assisted prostatectomy in the steep Trendelenburg position led to an increase in upper airway resistance directly after surgery that normalized within 24 h. The development of chemosis can be indicative of increased upper airway resistance. In patients without COPD, VC and FEV1 were reduced after surgery and recovered within 5 days, while in patients with COPD, the alteration lasted beyond 5 days.

Imaging Optimization of Temporal Bones With Cochlear Implant Using a High-resolution Cone Beam CT and the Corresponding Effective Dose.

To evaluate the impact of tube voltage, tube current, pulse number, and magnification factor on the image quality of a novel experimental set-up and the corresponding radiation. Six human temporal bones with cochlear implant were imaged using various tube voltages, tube currents, pulse numbers, and magnification. The effect of radiation was evaluated using a metaloxide semiconductor field-effect transistor (MOSFET) dosimeter device on an anthropomorphic RANDO RAN102 male head phantom. A copper and aluminum combination filter was used for hardware filtration. Overall, 900 frames, 11 mA, and 88 kV provided the best image quality. In temporal bones imaged with the optimized parameters, the cochlea, osseous spiral lamina, modiolus, stapes, round window niche, and oval window landmarks were demonstrated with anatomic structures still fully assessable in all parts and acceptable image quality. The most dominant contributor to the effective dose was bone marrow (36%-37 %) followed by brain (34%-36%), remainder tissues (12%), extra-thoracic airways (7%), and oral mucosa (5%). By increasing the number of frames, the image quality of the inner ear details obtained using the novel cone-beam computed tomography improved.

A review of the results from the German Wismut uranium miners cohort.

The Wismut cohort is currently the largest single study on the health risks associated with occupational exposures to ionising radiation and dust accrued during activities related to uranium mining. The cohort has ∼59 000 male workers, first employed between 1946 and 1989, at the Wismut Company in Germany. The main effect is a statistically significant increase in mortality from lung cancer with both increasing cumulative radon exposure and silica dust exposure. Risks for cancers of the extrathoracic airways, all extra-pulmonary cancers and cardiovascular diseases associated with radiation exposures have been evaluated. Cohort mortality rates for some other cancer sites, stomach and liver, are statistically significantly increased in relation to the general population, but not statistically significantly related to occupational exposures. No associations between leukaemia mortality and occupational doses of ionising radiation were found.

Efficient Nose-to-Lung (N2L) Aerosol Delivery with a Dry Powder Inhaler.

Delivering aerosols to the lungs through the nasal route has a number of advantages, but its use has been limited by high depositional loss in the extrathoracic airways. The objective of this study was to evaluate the nose-to-lung (N2L) delivery of excipient enhanced growth (EEG) formulation aerosols generated with a new inline dry powder inhaler (DPI). The device was also adapted to enable aerosol delivery to a patient simultaneously receiving respiratory support from high flow nasal cannula (HFNC) therapy. The inhaler delivered the antibiotic ciprofloxacin, which was formulated as submicrometer combination particles containing a hygroscopic excipient prepared by spray-drying. Nose-to-lung delivery was assessed using in vitro and computational fluid dynamics (CFD) methods in an airway model that continued through the upper tracheobronchial region. The best performing device contained a 2.3 mm flow control orifice and a 3D rod array with a 3-4-3 rod pattern. Based on in vitro experiments, the emitted dose from the streamlined nasal cannula had a fine particle fraction <5 μm of 95.9% and mass median aerodynamic diameter of 1.4 μm, which was considered ideal for nose-to-lung EEG delivery. With the 2.3-343 device, condensational growth in the airways increased the aerosol size to 2.5-2.7 μm and extrathoracic deposition was <10%. CFD results closely matched the in vitro experiments and predicted that nasal deposition was <2%. The developed DPI produced high efficiency aerosolization with significant size increase of the aerosol within the airways that can be used to enable nose-to-lung delivery and aerosol administration during HFNC therapy.

Mortality from cancers of the extra-thoracic airways in relation to radon progeny in the Wismut cohort, 1946–2008

Purpose: Inhalation of radon progeny can cause high lung and respiratory tract radiation doses. The aim of this paper was to examine the relationship between radon progeny and cancers of the extra-thoracic airways in the German uranium miner cohort for an extended follow-up through 2008.Methods: The cohort included 58,690 workers employed between 1946 and 1989 at the Wismut company. Exposure to radon progeny in Working Level Months (WLM) was determined from a comprehensive job-exposure matrix. The mean (max) cumulative exposure to radon among exposed cohort members (86%) was 280 WLM (3,224 WLM). Internal Poisson regression models were applied to estimate the linear Excess Relative Risk (ERR) per unit of cumulative exposure to radon.Results: A small increase in the mortality from all cancers of the extra-thoracic airways combined with increasing cumulative exposure to radon was found (ERR/100 WLM = 0.036, p = 0.12), based on 234 deaths. The estimated ERR per 100 WLM for relevant cancer sub-groups were: 0.017 (p > 0.5) larynx (n = 94); 0.077 (p = 0.20) pharynx (n = 74); and 0.030 (p > 0.5) tongue and mouth (n = 55).Conclusion: Results indicated a small but not statistically significant increase in mortality from cancers of the extra-thoracic airways in relation to radon. Low statistical power and uncontrolled confounding were limitations of this study.

Age-dependent inhalation doses to members of the public from indoor short-lived radon progeny.

The main contribution of radiation dose to the human lungs from natural exposure originates from short-lived radon progeny. In the present work, the inhalation doses from indoor short-lived radon progeny, i.e., (218)Po, (214)Pb, (214)Bi, and (214)Po, to different age groups of members of the public were calculated. In the calculations, the age-dependent systemic biokinetic models of polonium, bismuth, and lead published by the International Commission on Radiological Protection (ICRP) were adopted. In addition, the ICRP human respiratory tract and gastrointestinal tract models were applied to determine the deposition fractions in different regions of the lungs during inhalation and exhalation, and the absorption fractions of radon progeny in the alimentary tract. Based on the calculated contribution of each progeny to equivalent dose and effective dose, the dose conversion factor was estimated, taking into account the unattached fraction of aerosols, attached aerosols in the nucleation, accumulation and coarse modes, and the potential alpha energy concentration fraction in indoor air. It turned out that for each progeny, the equivalent doses to extrathoracic airways and the lungs are greater than those to other organs. The contribution of (214)Po to effective dose is much smaller compared to that of the other short-lived radon progeny and can thus be neglected in the dose assessment. In fact, 90% of the effective dose from short-lived radon progeny arises from (214)Pb and (214)Bi, while the rest is from (218)Po. The dose conversion factors obtained in the present study are 17 and 18mSv per working level month (WLM) for adult female and male, respectively. This compares to values ranging from 6 to 20mSvWLM(-1) calculated by other investigators. The dose coefficients of each radon progeny calculated in the present study can be used to estimate the radiation doses for the population, especially for small children and women, in specific regions of the world exposed to radon progeny by measuring their concentrations, aerosol sizes, and unattached fractions.

Inhalation pressure distributions for medical gas mixtures calculated in an infant airway morphology model

A numerical pressure loss model previously used for adult human airways has been modified to simulate the inhalation pressure distribution in a healthy 9-month-old infant lung morphology model. Pressure distributions are calculated for air as well as helium and xenon mixtures with oxygen to investigate the effects of gas density and viscosity variations for this age group. The results indicate that there are significant pressure losses in infant extrathoracic airways due to inertial effects leading to much higher pressures to drive nominal flows in the infant airway model than for an adult airway model. For example, the pressure drop through the nasopharynx model of the infant is much greater than that for the nasopharynx model of the adult; that is, for the adult-versus-child the pressure differences are 0.08 cm H2O versus 0.4 cm H2O, 0.16 cm H2O versus 1.9 cm H2O and 0.4 cm H2O versus 7.7 cm H2O, breathing helium–oxygen (78/22%), nitrogen–oxygen (78/22%) and xenon–oxygen (60/40%), respectively. Within the healthy lung, viscous losses are of the same order for the three gas mixtures, so the differences in pressure distribution are relatively small.

Effect of Electrostatic Charge on Deposition of Uniformly Charged Monodisperse Particles in the Nasal Extrathoracic Airways of an Infant

The fraction of inhaled particles depositing in the nasal extrathoracic airways determines the amount of particles delivered to the lungs of infants. Electrostatic charge on particles can affect this deposition, and for this reason, deposition of charged aerosol particles in the Alberta Idealized Infant nasal geometry is examined. Charged aerosol particles were generated via Plateau-Rayleigh jet breakup atomization with induction charging. Nasal deposition was measured by collecting particles on a filter membrane at the inlet and outlet of the airway and measuring their mass with an ultramicrobalance. The experiments were carried out using monodisperse, uniformly charged particles with aerodynamic diameters of 3-6 μm at two flow rates of 7.5 and 15 L/min, for a charge range of 0-10,000 e per particle. Electrostatic charge effects are largest for the lowest flow rate, smallest particle size, and highest charge level, with deposition in this case being approximately three times that for neutral particles. Higher flow rates and larger particle size result in much weaker electrostatic effects, with even the highest charge levels giving only a few percent higher deposition for the largest particle size and flow rate considered in this study. A dimensionless empirical relation based on the experimental data was developed for predicting deposition of charged particles in the idealized infant airway. Electrostatic charge on inhaled aerosol particles has only a minor effect on deposition for large particles at higher flow rates, because in this case inertial impaction dominates deposition. However, for particles with low inertia, for example, small particles or low flow rates, large values of electrostatic charge strongly increase nasal deposition in the present infant extrathoracic airway.