Modeling age-related particle deposition in humans

Area of Science:

• Environmental Health
• Toxicology
• Biomedical Engineering

Background:

• Inhalation of airborne particles poses health risks, particularly to children.
• Limited understanding of particle fate in pediatric respiratory tracts due to lack of age-specific lung geometry data.

Purpose of the Study:

• To develop age-specific lung geometries for children and adults.
• To model particle deposition in different lung regions and lobes across various ages.
• To assess age-dependent health risks from inhaled airborne materials.

Main Methods:

• Utilized lung morphometry data from 3 months to 21 years to create 5-lobe lung geometries.
• Employed a multiple-path particle deposition model with simulated resting breathing patterns.
• Developed age-dependent, semi-empirical expressions for nasal particle losses.

Main Results:

• Nasal deposition was higher in adults than children. Tracheobronchial deposition patterns were similar across ages for a given particle size.
• Alveolar deposition varied with age without a clear trend. Lobar deposition was proportional to lobar air volume.
• Adjusted tracheobronchial and pulmonary deposition fractions were highest in infants, decreasing with age. Ultrafine particles distributed more uniformly than coarse particles.

Conclusions:

• Children, particularly infants, may face greater health risks from airborne particulate matter.
• Age-dependent particle deposition patterns have implications for inhaled reference concentrations.
• Findings inform site-specific delivery of drugs and therapeutic compounds to pediatric lungs.