interesting study.

a minor point, "patency" is the "openness" of the airway, without regard to how it is measured. The authors use "subjective nasal patency" to discuss the reported sensation and just say "airflow" when they are talking about flow measured by rhinomanometry

good find and very interesting points in there, including the lack of understanding on where, exactly, cold sensory areas are located, and the question that menthol may have a direct effect on lowering respiratory drive