There is a paucity of data regarding mechanisms and effects of inhaled environmental particulate matter on athletic performance. To formulate a framework on which future studies may be developed relating regional airway deposition to subsequent performance in athletes, modeling is indicated. Multiple-Path Particle Dosimetry (MPPD) computer modeling was utilized to predict the deposition of inhaled particles in 26 male athletes at increasing levels of exertion. Deposition doses of inhaled spherical, monodisperse particles of unit density (1 g/cm(3)) measuring 0.05, 0.1, 1.0, 2.5, and 10.0 mu m in diameter were calculated. Repeated measures ANOVA testing was used to test for differences in total and regional (naso-oro-pharyngolaryngeal, tracheobronchial, and pulmonary) airway deposition at exertion. Increasing exertion revealed statistically significant effects (p < 0.01) on deposition of all particle sizes in all airway regions. Overall total airway modeled deposition dose of all particle diameters increased as expected with increasing minute ventilation. Pulmonary deposition dose at exertion tapered off and decreased in the case of larger particles (2.5 and 10.0 mu m), indicating that deposited doses in the pulmonary region (deep lung) may be reduced by greater deposition in larger airways at higher levels of exertion, depending on particle aerodynamic diameter. To assess the impact of inhaled particulate matter on athletic performance, understanding regional deposition and subsequent physiologic impacts are critical steps. Future studies should focus on modeling realistic exposures and performing studies to elucidate mechanisms of injury in both bronchial and pulmonary airways that might impact performance. (C) 2016 Elsevier Ltd. All rights reserved.