Flow rate selection depends on the size of allergen particles to achieve optimal nasal irrigation.

The clearance efficiency of allergen particles during nasal irrigation is a quantitative standard for evaluating the effectiveness of nasal irrigation. Due to the difficulty in obtaining various parameters in in vivo experiments, this study aims to establish a numerical model of the nasal cavity based on CT scan images of healthy adults. We chose four different levels of allergen particles, PM1, PM5, PM10, and PM25, as the subjects. A quantitative analysis was conducted to determine the clearance efficiency of the four levels of allergen particles by five different inlet flow rates of the irrigation solution. The results showed that the clearance efficiency of PM1 allergens was optimal at the inlet flow rate of 1.8 [Formula: see text], equivalent to 2.10 [Formula: see text]. In summary, selecting an appropriate flow rate is necessary to achieve the best clearance efficiency for different levels of allergen particles.