The Effect of Ventilation, Age, and Asthmatic Condition on Ultrafine Particle Deposition in Children

Abstract

Ultrafine particles (UFPs) contribute to health risks associated with air pollution, especially respiratory disease in children. Nonetheless, experimental data on UFP deposition in asthmatic children has been minimal. In this study, the effect of ventilation, developing respiratory physiology, and asthmatic condition on the deposition efficiency of ultrafine particles in children was explored. Deposited fractions of UFP (10–200 nm) were determined in 9 asthmatic children, 8 nonasthmatic children, and 5 nonasthmatic adults. Deposition efficiencies in adults served as reference of fully developed respiratory physiologies. A validated deposition model was employed as an auxiliary tool to assess the independent effect of varying ventilation on deposition. Asthmatic conditions were confirmed via pre-and post-bronchodilator spirometry. Subjects were exposed to a hygroscopic aerosol with number geometric mean diameter of 27–31 nm, geometric standard deviation of 1.8–2.0, and concentration of 1.2 × 106 particles cm−3. Exposure was through a silicone mouthpiece. Total deposited fraction (TDF) and normalized deposition rate were 50% and 32% higher in children than in adults. Accounting for tidal volume and age variation, TDF was 21% higher in asthmatic than in non-asthmatic children. The higher health risks of air pollution exposure observed in children and asthmatics might be augmented by their susceptibility to higher dosages of UFP.

A Set-up for Respiratory Tract Deposition Efficiency Measurements (15-5000 nm) and First Results for a Group of Children and Adults

“…Children have been identified as a potentially sensitive group to air pollution, and efforts have been made to understand the particle deposition in the lungs of children (e.g., Smith et al, 2001;Asgharian, 2004;Bennett and Zeman, 2004;Olvera et al, 2012). In this study we found that for children, DF, TDF, and Drate were generally higher than for the adult group.…”

“…Most measurements of the deposition of inhaled particles have been carried out on healthy (male) adults, but some also include children (Becquemin et al, 1991;Schiller et al, 1992;Schiller-Scotland et al, 1994;Bennett and Zeman, 1998;Smith et al, 2001;Bennett and Zeman, 2004;Isaacs and Martonen, 2005;Olvera et al, 2012), elderly people (Kim et al, 1988;Bennett et al, 1996;Kim and Jaques, 2005), and patients with airway diseases (e.g., Kim et al, 1988;Schiller-Scotland et al, 1996;Bennett et al, 1997;Brown et al, 2002;Chalupa et al, 2004;Möller et al, 2008;Löndahl et al, 2012). The studies are not fully conclusive, but several of them report an increased respiratory tract deposition for patients with lung diseases and for children.…”

Novel multi-functional europium-doped gadolinium oxide nanoparticle aerosols facilitate the study of deposition in the developing rat lung

“…33 Studies in human subjects have shown left/right lobe differences in particle deposition that is effected by breathing pattern and disease state. 34, 35 Therefore, it is reasonable to observe difference in lung lobe-to-lobe distribution of particles.…”

Deposition efficiency of inhaled particles (15-5000 nm) related to breathing pattern and lung function: an experimental study in healthy children and adults

“…The information on parameters that determine inter-subject variability is very limited, partly because most measurements are made for controlled breathing over a narrow particle size interval. Experimental data on DF for children are almost completely lacking [20, 22, 23]. Furthermore, there are substantial methodological uncertainties [24].…”