Impact of neck angle variation on particle and virus-laden droplet transport from lung to lung using eighth-generation airway model

In this study, the motion of particles from the respiratory tract of an infected person to that of an exposed person was simulated using computational fluid dynamics. The angle of the exposed person's neck was varied from 0 ° to 20 ° to assess its impact on particle motion. The airway models for the infected and exposed individuals were based on software and CT data, respectively. Particles, generated 1.5 cm from the exposed person's mouth, were analyzed for deposition on the lung inlet patches, considering the suction effect. The study focused on correlations between the neck angle changes and particle size, excluding considerations of evaporation, death, and coalescence. Results showed larger particles (>15 µm) were not suctioned in and fell, with size influencing attachment locations in the respiratory tract. In virus-laden droplet simulations, the droplets generated inside the infected person's bronchi were tracked over 60 s. Most of the droplets dispersed in the space were less than 3.0 µm, and the amount of droplets adhering to the lung inlet patches was characteristic. Notably, the data on particle and droplet volumes adhering to specific lung regions at different neck angles and time intervals provide insights for devising efficient drug inhalation methods to mitigate disease progression at targeted lung locations. Additionally, this information aids in understanding the susceptibility of specific lung regions to pulmonary diseases on the basis of virus-laden droplet distribution.