Figure 5

(a) Illustration depicting nasal spray usage, as per instructions³⁸ that come with over-the-counter sprays. Panel (b) and inset (c) depict the protocol implemented in the numerical simulations for the “Current Use” (CU) spray orientation. Note that δ is the linear distance between lateral wall and septum (the cartilaginous “mid-wall” in the nose, separating right and left airways) at 5-mm insertion depth into the nose. The model “head” is tilted forward by 22.5°. The vertically upright dashed line represents the spray nozzle axis.