Nasal mucous transport and our ambient air.

The nose usually serves to conduct air in and out of the lungs; but it also defends the body against airborne noxious materials and modifies the physical condition of inspired air prior to its arrival in the lungs. A major factor in these physiological functions is mucociliary clearance which depends on the secretion of airway secretions and ciliary activity. This function is impaired by certain air pollutants, but not by relative humidity or temperature of the ambient air.