In COPD and emphysema, the confluence of disrupted species transport, compromised air flow, and altered chemical reactions profoundly affects disease progression. In COPD, chronic inflammation leads to structural remodeling of the airways, exacerbating diffusion limitations and obstructing airflow . Emphysema is characterized by alveolar destruction, which decreases the surface area for gas exchange, further impairing diffusion . These pathogenic mechanisms not only disrupt biophysical homeostasis stability but also compromise biomechanical functions. For example, airway remodeling in COPD increases airway resistance, requiring higher pressures for ventilation and thus increasing the work of breathing . In emphysema, the loss of elastic recoil and ensuing air trapping worsens lung mechanics, reducing lung compliance and leading to hyperinflation . The flow chart in Figure schematically details the roles of transport and transformation in the pathogenesis of COPD. The COPD disease etiology begins with the transport of particulate species from the ambient environment through the respiratory tract, which elicits some inflammatory responses from the immune cells, followed by a transformative remodeling of the epithelial tissue (fibrosis). Further transformation results in the hypersecretion of mucus, which limits airflow due to the narrowing of the affected respiratory tract (bronchioles). The plugged bronchioles restrict the transport of oxygen molecules (O2) and carbon dioxide (CO2) in and out of the respiratory tract. The constrained gaseous transport reduces the amount of O2 diffusing across the alveoli membrane into the capillary while CO2 accumulates within the alveolar sac. This phase of COPD, which consists of inflammation due to immune cells' sensitivity to particulate species and excessive mucus secretion to airway obstruction, leads to chronic bronchitis. The next COPD phase, which involves alveolar wall destruction and irregular gas exchange, results in emphysema . The detailed flow scheme of species transport and transformation in emphysema's pathogenesis is portrayed in Figure .