The effects of density on particle deposition in the human respiratory tract

![CDATA[Particle transport and deposition (TD) are influenced by lung structure, breathing patterns, and particle shape and sizes. Therefore, it is essential to assess different density particles TD in human lung airways for the effectiveness of inhaled drugs. Much research has been conducted to understand the effects of particle size on TD in the lungs. However, the effect of particle density on the particle TD in the lung airways has not to be addressed. The present study investigates TD of particles of four diameters (1μm, 3 μm, 7 μm and 10 μm) and two densities (400 kg/m3 and 2200 kg/m3) in generations 0 to 4 airways of a human lung using computational fluid dynamics (CFD). The flow rate corresponding to intense physical activity (Qin=60 L/min) is considered during the simulation. The deposition rate of larger density (2200 kg/m3) particles is higher than that of lower density (400 kg/m3). According to the findings, 68.7% of particles with the largest diameter (10 μm) and lower density (400 kg/m3) can pass generation 4 and enter the deep lung. In comparison, 10.83% of particles with the largest diameter (10 μm) and higher density (2200 kg/m3) can pass generation 4 and go to the deep lung. The present study's findings would help the targeted drug delivery in human lung airways.]]