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The sinus probably originated as an outgrowth of the cranial pneumatic system, though it cannot yet be determined which of the various of these systems it was linked to – the paranasal, paratympanic or pharyngeal one.

Another study a year later in The European Respiratory Journal found a similar effect: humming resulted in a large increase in nasal nitric oxide, “caused by a rapid gas exchange in the paranasal sinuses.”