Breath of impact: Unveiling the dynamics of exhalation-driven deposition of polydisperse particles in lung across varied physical activities

Continuous deposition of workplace pollutant particles on lung airways during respiratory actions seriously threatens the lung health of persons performing tasks in polluted environments. This study aims to analyze the exhalation-driven deposition of fine and coarse occupational pollutant particles in polydisperse form. Computer simulations are conducted to study the patterns of deposition of grain dust, coal fly ash, and bituminous coal particles. Key findings include the observation of early emergence of secondary flows in the real model, a notable shift in deposition patterns towards the post-bifurcation zones, and influence of physical activity intensity on particle deposition. Additionally, deposition primarily occurs near cranial ridge during inhalation, while exhalation leads to deposition in pre- and post-bifurcation zones. PM2.5 deposition is minimal and random in idealized model but becomes more significant and consistent in real model. This research underscores the increased risk of lung diseases for workers in polluted environments during vigorous activity. • Analysis of exhalation-driven deposition informs pollutant health risks. • Active physical conditions increase deposition. • Deposition comparison of fine (PM2.5) and coarse (PM2.5–10) particles. • High density particles influence lungs health more. • Gravity impact: strong at low flow, weak at high flow when normal to gravity.